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Autodesk Moldflow Insight Standard 2 P RACTICE FOR R ELEASE 2010 February 2009

Autodesk Moldflow Insight 2010 Std2 Practice

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Autodesk Moldflow Insight 2010 Std2 Practice

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  • Autodesk Moldflow

    Insight Standard 2

    PRACTICEFOR RELEASE 2010

    February 2009

  • 2009 Autodesk, Inc. All rights reserved.Except as otherwise permitted by Autodesk, Inc., this publication, or parts thereof, may not be reproduced in any form, by any method, for any purpose. Certain materials included in this publication are reprinted with the permission of the copyright holder.

    Trademarks

    The following are registered trademarks or trademarks of Autodesk, Inc., in the USA and other countries: 3DEC (design/logo), 3December, 3December.com, 3ds Max, ADI, Alias, Alias (swirl design/logo), AliasStudio, Alias|Wavefront (design/logo), ATC, AUGI, AutoCAD, AutoCAD Learning Assistance, AutoCAD LT, AutoCAD Simulator, AutoCAD SQL Extension, AutoCAD SQL Interface, Autodesk, Autodesk Envision, Autodesk Insight, Autodesk Intent, Autodesk Inventor, Autodesk Map, Autodesk MapGuide, Autodesk Streamline, AutoLISP, AutoSnap, AutoSketch, AutoTrack, Backdraft, Built with ObjectARX (logo), Burn, Buzzsaw, CAiCE, Can You Imagine, Character Studio, Cinestream, Civil 3D, Cleaner, Cleaner Central, ClearScale, Colour Warper, Combustion, Communication Specification, Constructware, Content Explorer, Create>what's>Next> (design/logo), Dancing Baby (image), DesignCenter, Design Doctor, Designer's Toolkit, DesignKids, DesignProf, DesignServer, DesignStudio, Design|Studio (design/logo), Design Web Format, DWF, DWG, DWG (logo), DWG Extreme, DWG TrueConvert, DWG TrueView, DXF, Ecotect, Exposure, Extending the Design Team, FBX, Filmbox, FMDesktop, Freewheel, GDX Driver, Gmax, Green Building Studio, Heads-up Design, Heidi, HumanIK, IDEA Server, i-drop, ImageModeler, iMOUT, Incinerator, Inventor, Inventor LT, Kaydara, Kaydara (design/logo), Kynapse, Kynogon, LandXplorer, LocationLogic, Lustre, Matchmover, Maya, Mechanical Desktop, MotionBuilder, Movimento, Mudbox, NavisWorks, ObjectARX, ObjectDBX, Open Reality, Opticore, Opticore Opus, PolarSnap, PortfolioWall, Powered with Autodesk Technology, Productstream, ProjectPoint, ProMaterials, RasterDWG, Reactor, RealDWG, Real-time Roto, REALVIZ, Recognize, Render Queue, Retimer,Reveal, Revit, Showcase, ShowMotion, SketchBook, SteeringWheels, Stitcher, StudioTools, Topobase, Toxik, TrustedDWG, ViewCube, Visual, Visual Construction, Visual Drainage, Visual Landscape, Visual Survey, Visual Toolbox, Visual LISP, Voice Reality, Volo, Vtour, Wiretap, and WiretapCentral.

    The following are registered trademarks or trademarks of Autodesk Canada Co. in the USA and/or Canada and other countries: Backburner, Discreet, Fire, Flame, Flint, Frost, Inferno, Multi-Master Editing, River, Smoke, Sparks, Stone, and Wire.

    The following are registered trademarks or trademarks of Moldflow Corp. in the USA and/or other countries: Moldflow MPA, MPA (design/logo), Moldflow Plastics Advisers, MPI, MPI (design/logo), Moldflow Plastics Insight, MPX, MPX (design/logo), Moldflow Plastics Xpert.

    Disclaimer

    THIS PUBLICATION AND THE INFORMATION CONTAINED HEREIN IS MADE AVAILABLE BY AUTODESK, INC. "AS IS." AUTODESK, INC. DISCLAIMS ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE REGARDING THESE MATERIALS.

  • About this manualThe Autodesk Moldflow Insight Standard 2, Practice manual is designed with the new Moldflow user in mind. In creating this manual, our goal was to introduce you to some basic plastic flow and design principles in addition to skills needed to translate, analyze and interpret models.

    There is a significant amount of information in this manual, more information than can be absorbed during the class. This manual should be useful as a handy desk reference when back in the office.

    Using this manual

    This manual is separated into several chapters and appendices. Each of the chapters covers a specific topic and includes the following sections:

    Aim

    Describes the learning objectives of the chapter.

    Why Do It

    Outlines the reasons for following the prescribed guidance, suggestions, and methodology within the chapter.

    Overview

    A complete outline of what will be covered within the chapter.

    Practice

    This section contains hands-on exercises used to reinforce what was learned. The practice section guides the user through the steps necessary to complete a project.v

  • Formatting used in this manualTasks

    : To perform a step on the computer1. When the Task icon is shown, below it is a list of numbered steps to complete the

    task.

    1.1. Tasks can have a sub-step,

    A bulleted list provides information on a step, or a non-sequential actions to be done,

    h A second level bulleted list to provide information on a sub-step.2. A task is used in the practice section of a chapter to indicate steps to be done on the

    computer.

    Bulleted lists

    A bulleted list contains a number of items that have no particular order. It does not represent a list of steps that have to be followed in sequence.

    Ruled paragraph

    Tip

    Note

    Text from a computer screen is shown between ruled lines.

    / A tip is a useful piece of information that is normally associated with a task or procedure. Something that can be done to make a task easier or more efficient.

    3 A note is generally used to highlight some background or theoretical information.vi

  • Training files setupThe files required for the Autodesk Moldflow Insight Standard 2 class are organized into several folders. Each folder has the files necessary for one chapter. The table below shows the required folders, translation and study files, and results necessary for the class. In each folder, there will be a *.mpi file with the same name as the folder. The mpi file is the database of the Project pane in Synergy. All the results that need to be run will be provided in class. However if for some reason the results are not available, they can be obtained by analyzing the necessary studies.

    Table 1: Files Required for the Autodesk Moldflow Insight Standard 2 Class

    Folder name Files Needed Results neededDatabase_Management Cover.sdy

    Mat1804.21000.udbMat1805.21000.udb

    DOE Cap.sdyPlate.sdy

    Fill + Pack + DOE on Cap

    Family_Tools Box.sdyLid.sdy

    Insert Overmolding Insert DDConnector DDConnector 3D Pre-Run

    Fill + Pack on Connector 3D Pre-Run

    Multiple_Gates door_panel.sdyDrawer.sdy

    Packing_Optimization SC Fill.sdySC Flat Prof.sdySC3 Fill.sdySC3 Flat Prof.sdy

    NoneCoolNoneCool

    Projects Boot.igsCap.igsChange_tray.igsCover.igsDrawer.igsDustpan.igsGrabit.igsLight_holder.igePaper_Holder.igsphone.igsreel.igsSnap_Cover.igsvii

  • Table 1: Files Required for the Autodesk Moldflow Insight Standard 2 ClassTwo-Shot Box DDWindow DDBox & Window Pre-RunMF Logo DDMF Back DDMF Back & Logo Pre-RunMF Back & Logo Test match

    Fill + Pack + Overmolding Fill +Pack onConnector 3D Pre-Run,MF Back & Logo Pre-Run,MF Back & Logo Test match

    Folder name Files Needed Results neededviii

  • Contents

    About this manual ........................................................................................................................vUsing this manual .........................................................................................................................vFormatting used in this manual .................................................................................................viTraining files setup .....................................................................................................................vii

    CHAPTER 1Database Management ........................................................................... 1

    Practice - Database Management ............................................................................................... 3Setup ....................................................................................................................................3Creating a personal database ............................................................................................3Edit a material property ....................................................................................................5Read in a Personal Database material into a study .......................................................5Competency check - Database Management ................................................................ 7Evaluation Sheet - Database Management .................................................................... 9

    CHAPTER 2Family Tools .......................................................................................... 11

    Practice - Family Tools .............................................................................................................. 13Design criteria ..................................................................................................................13Project setup .....................................................................................................................13Finding molding conditions and optimizing the parts ..............................................14Building the family tool model ......................................................................................19Analyzing the tool ...........................................................................................................21Competency check - Family Tools ............................................................................... 25Evaluation Sheet - Family Tools ................................................................................... 27

    CHAPTER 3Multiple Gates ........................................................................................ 29

    Practice - Multiple Gates ........................................................................................................... 31Drawer Model .................................................................................................................. 33Door Panel ....................................................................................................................... 45Competency check - Multiple Gates ............................................................................ 59Evaluation Sheet - Multiple Gates ................................................................................ 61

    CHAPTER 4Packing Optimization ............................................................................ 63

    Practice - Packing Optimization............................................................................................... 65Snap cover with a Dual Domain mesh ........................................................................ 67Snap cover with a 3D mesh ........................................................................................... 85Competency check - Packing Optimization............................................................. 101Evaluation Sheet - Packing Optimization................................................................. 103ix

  • CHAPTER 5Part Insert Overmolding ......................................................................105Practice - Part insert overmolding......................................................................................... 107Connector ...................................................................................................................... 109

    CHAPTER 6Two-Shot Sequential Overmolding ....................................................127

    Practice - Two-Shot Sequential Overmolding..................................................................... 129Box with window.......................................................................................................... 131Moldflow logo............................................................................................................... 139

    CHAPTER 7Design of Experiments (DOE) Analysis .............................................155

    Practice - Design of Experiments (DOE) Analysis............................................................ 157Plate ................................................................................................................................ 158Reviewing the results of the cap ................................................................................ 160Answers.......................................................................................................................... 164Competency check - DOE ......................................................................................... 165Evaluation Sheet - DOE ............................................................................................. 167

    CHAPTER 8Projects .................................................................................................169

    Finding a gate location on a boot part ..................................................................................171Optimize the 8-cavity tool for cap .........................................................................................172Determine gate location and molding conditions for a change tray .................................174Find the gate location and size the runner system for a cover ..........................................176Determine gate locations for a chest of drawers .................................................................178Finding a gate location for a dustpan ....................................................................................179Determine type of tool and gate location for the Grab-it model ......................................180Determine the gate location for a light holder .....................................................................181Determine the gate location for the paper holder model to minimize weld lines ..........182Find a gate location and process settings for the phone housing model .........................183Find a gate location and size the manifold for the reel model ..........................................184Optimize a 4-cavity tool for the Snap Cover model ...........................................................186Find gate locations and balance runners for the door panel model .................................188What Youve Learned ..............................................................................................................189

    Index ............................................................................191x

  • CHAPTER 1Database Management

    Aim

    The aim of this chapter is to create or edit databases.

    Why do it

    Customizing databases allows you to create material that is not in standard databases, or to change the values of something that is in a standard database. Most of the time this is a thermoplastic material, but it could also be geometry/mesh properties. You can even edit the defaults for all parameters that are used within the program. Editing databases can be done so you can run an analysis on a custom material, or in the case of geometry databases, create the standard geometry you use.

    Overview

    There are several methods available for creating, editing and using databases. In this chapter, you will look at the methods available for working with the databases. The method used will depend on what you are editing and why. Many times you may start by copying an existing material or database record and then modify it. You may also create a new database and enter all the information manually.Database Management 1

  • 2 Chapter 1

  • Practice - Database ManagementBelow are 3 short examples of working with personal databases

    Setup

    To open a project1. Click (File Open Project) and navigate to the folder

    My AMI 2010 Projects\AMI Standard 1\Database_Management.

    2. Double click the project file Database_Management.mpi.

    3. Click File Preferences.3.1. Ensure the active units are set to metric units.

    To open the cover model1. Click on the file Cover. sdy, and click Open.

    2. Rotate the model around to review the geometry.

    Creating a personal database

    To create a personal material database 1. Click ToolsNew Personal Database.2. Ensure the Category field is set to Material in the drop-down menu, See Figure 1.

    3. Select the Property Type field to Thermoplastics Material.

    4. Name your personal database by clicking on and typing mymatdb.

    5. Click the Save button.

    6. Click the OK button.

    The Properties dialog opens as shown in Figure 2.

    To read in existing UDB databases1. Click button to access all other thermoplastic databases.

    The standard database is opened automatically.

    2. Click to the right of the database name field.

    2.1. Navigate to the Database management folder.

    h This is the folder in which Synergy is open.Practice - Database Management 3

  • 3. Click on the file mat1804.21000.udb then click the open button.

    The contents of this database should now be in the lower half of the properties

    dialog.

    4. Highlight the material in the mat1804.21000.udb database.

    5. Click the button twice to transfer the material to your personal database in the top half of the dialog making two copies.

    6. Click the icon again and read in mat1805.2100.udb.

    Copy that material to the personal database.

    Figure 1: New database dialog

    / To select more than one entry, hold down the Ctrl key while clicking on multiple entries.

    / If you have read in a database and dont see any materials or not all of them, open the search criteria dialog and clear the filters.

    3 The file mat1804.21000.udb is the type of file you would get from Moldflow Plastics Labs when you had a material tested.4 Chapter 1

  • Figure 2: Properties dialog

    Edit a material property

    In the mymatdb database, there should be two copies of the material Styron 693.

    To edit a material1. Click to highlight the second copy of the Styron 693.

    2. Click the button.

    3. Click on the Recommended Processing tab.

    4. Change the Mold surface temperature from 42.5C to 50C

    5. Change the Melt temperature from 225C to 250C.

    6. Change the Name to Styron 693: Changed Mold and Melt.

    7. Click on the Description tab.

    8. Change the Trade name to Styron 693mod.

    9. Click OK.

    10. Click OK on the Propertys dialog to close the dialog and finish the editing.

    Read in a Personal Database material into a study

    To find the material1. If the cover study is not open, click on the icon in the project view to open it.

    2. Double-click (Materials) to select a material.

    3 The Name field in the thermoplastic material dialog is the description field from a search listing. For the material you just entered, the description is Styron 693: Changed Mold and Melt.Practice - Database Management 5

  • 3. In the Manufacturer field, type my. This should find your database Mymatdb.

    4. Tab to the Trade name field.5. Select Styron 693.

    6. Click OK to select the material.

    To check the processing conditions1. Double-click (Process Settings).

    2. Check the value of the Mold surface temperature and Melt temperature.

    They should be 42.5C and 225C respectively. These are the original values.3. Click Cancel to close the Process Settings dialog.

    To read in the second Styron4. Double-click (Materials) to select a material.

    5. In the Manufacturer field, type my. This should find your database Mymatdb

    6. Tab to the Trade name field.

    7. Select Styron 693mod.

    8. Click OK to select the material.

    To check the processing conditions1. Double-click (Process Settings).

    2. Check the value of the Mold surface temperature and Melt temperature.

    They should be 50C and 250C respectively. These are the modified values.3. Click Cancel to close the Process Settings dialog.6 Chapter 1

  • Competency check - Database Management1. What would be the procedure necessary to create a database for standard edge and tunnel gates your company uses?Practice - Database Management 7

  • 8 Chapter 1

  • Evaluation Sheet - Database Management1. What would be the procedure necessary to create a database for standard edge and tunnel gates your company uses?

    1. Click ToolsNew personal database.2. Enter a database name such as Mygates.

    3. Select the category Mesh properties.

    4. Select the property type Cold gate.

    5. Click the Databases button to open the standard cold gate database. (Optional).

    6. Copy an edge and tunnel gate (subgate) that are close to the correct properties. (Optional).

    7. Edit the properties as necessary.

    8. Exit the dialog.Practice - Database Management 9

  • 10 Chapter 1

  • CHAPTER 2Family Tools

    Aim

    In this chapter you will create a family tool and size the runners, so that both cavities fill in the same amount of time and pressure.

    Why do it

    The purpose of a family tool is to reduce the number of molds needed by combining multiple parts (two or more) into a single mold. Typically, the parts will be assembled together. The reasoning behind this is usually due to cost reduction measures.

    Although it is possible to place two or more different parts into the same mold, it will cause a problem with unbalanced filling. Therefore, it is necessary to balance the filling of the multiple cavities via the runner system.

    Overview

    This chapter uses midplane models in the practice. The runner balancing procedure being discussed in this chapter can be applied to both Dual Domain and midplane models. Family tools can be analyzed in 3D but their runners can't be balanced in the methods discussed in this chapter. A Dual Domain version of the models can be created for the purpose of balancing the runners then verified in the 3D model.

    In this practice, you will optimize process settings for a family tool, and build and balance its runner system.

    The main challenge in using family tools is that the parts usually have different volumes and require different pressures to fill. This chapter demonstrates how to overcome this challenge by following these steps:

    1. Use the Molding Window analysis to find a set of processing conditions that will work for both parts.

    2. Run a Fill analysis for both parts to verify that the process settings selected work, optimize the part filling, and find the part volumes.

    3. Add the models together and create the runner system for the new model.

    4. Change to flow rate control, using the combined part volumes, and run a Fill analysis.Family Tools 11

  • 5. Size the runners to achieve the desired balance using flow rate and the runner balancing. 3 For some larger family tools where each part has multiple gates, it may be more efficient to size the runners manually.12 Chapter 2

  • Practice - Family ToolsIn this section, you will analyze the Box and Lid and balance the runner system for the two cavity family tool.

    Design criteria

    Determine the molding conditions that will work for both parts to mold high quality parts. Build and size a runner system so both parts fill at the same time. The mold will be a 3-plate tool.

    Project setup

    To open a project1. Click (File Open Project) and navigate to the folder

    My AMI 2010 Projects\AMI Standard 1\Family_Tools.

    2. Double-click the project file Family_Tools.mpi.

    3. Click File Preferences.3.1. Ensure the active units are set to metric units.

    3.2. Click on the Directories tab.

    3.3. Ensure the Default to project directory box is checked.

    By having the box checked, the import dialog will open in the project directory.The next task loads a workspace customized for training classes. Primarily, it introduces you to the toolbars. This is an optional task.

    To load a workspace for training (optional)1. Click ToolsWorkspace Open.2. Select Other... in the Type field.

    3. Navigate to the Workspaces folder containing the project folders for this class and click OK.

    For example My AMI 2010 Projects\AMI Standard 1\Workspaces.Practice - Family Tools 13

  • 4. Select the workspace file Training Workspace and click Open.

    The workspace will load. Primarily, it opens a series of toolbars and leaves them

    undocked so you can see the name of the toolbars. Toolbars with the word Custom in the name are not standard toolbars but were created as an example of tool bars that can be made. The toolbars include:

    5. Click and drag the toolbars and dock them where you would like them.

    Typically the Viewer toolbar is docked vertically between the Tasks panel and the display area. The rest are typically docked below the menu bar.

    To review the model1. Open both models.

    2. Investigate the model geometry using the model manipulation tools.

    Finding molding conditions and optimizing the parts

    The molding conditions will be found by using the molding window analysis. The box and lid will be analyzed separately, then the Molding window results will be compared to find the same conditions that work for both parts. The molding window will be done twice for both parts. The first time with default options. From this, the injection time range will be determined. Then, a molding window analysis will be run with specified ranges for mold and melt temperatures, and injection time. The preferred and feasible molding windows will also be defined.

    The part geometries are very simple for these parts so part optimization is just a matter of running a fill analysis to make sure the molding conditions are good. For more complex parts, optimization may involve solving any type of flow problem that is found.

    To run a molding window analyses on the box with default conditions1. Activate the Box study.

    2. Click (File Save study as) and enter Box MW1.3. Click (Analysis Sequence) and select Molding Window.

    4. Click (Select material) and find BASF, Luran 368 R.

    Standard. Viewer. Animation Precision View Viewpoint. Selection Scaling. Custom General. Custom Results. Custom Mesh Diag. Custom Mesh Tools. Custom Locking.

    3 To get back to the default layout, click ToolsWorkspace Open and in the Moldflow Insight workspaces type, select Defaults.14 Chapter 2

  • 5. Click (Start Analysis) to run the Molding Window analysis. To view the results for the box1. Open the Analysis Log and record in Table 1, the range of mold and melt

    temperatures analyzed.

    2. Click Pressure drop, maximum (molding window):XY Plot to display it.

    3. Click (Results Plot Properties).4. Move the Injection time slider to find the minimum and maximum time plotted.

    5. Record the minimum and maximum times in Table 1.

    6. Check the Injection time box and move the sliders to ensure the pressure is not too high.

    7. Click Close to exit the Explore Solution Space dialog.

    To run a molding window analyses on the lid with default conditions1. Activate the Lid study.

    2. Click (File Save study as) and enter Lid MW1.3. Click (Analysis Sequence) and select Molding Window.

    4. Click (Select material) and find BASF, Luran 368 R.

    5. Click (Start Analysis) to run the Molding Window analysis.

    To view the results for the Lid1. Click Pressure drop, maximum (molding window):XY Plot to display it.

    2. Click (Results Plot Properties).3. Move the Injection time slider to find the minimum and maximum time plotted.

    4. Record the minimum and maximum times in Table 1.

    5. Compare the injection time ranges and determine the minimum and maximum common to both studies.

    6. Record the values in Table 1.Practice - Family Tools 15

  • To run a molding window analysis on the box with specified parameters1. Activate the Box MW1 study.

    2. Click (File Save Study).

    3. Click (File Save study as) and enter Box MW2.

    4. Double-click (Process Settings) in the Study Tasks pane.

    4.1. Click the Edit button in the Injection molding machine frame.

    4.2. Click the Hydraulic Unit tab.

    4.3. Set the maximum machine injection pressure to 140 MPa.

    4.4. Click OK to exit the dialog.

    5. Set the Mold temperature range to analyze to Specified, and enter the range recorded in Table 1.

    6. Set the Melt temperature range to analyze to Specified, and enter the range recorded in Table 1.

    7. Set the Injection time range to analyze to Specified, and enter the range recorded in Table 1.

    8. Click the Advanced options button.

    8.1. Set the injection pressure factor to 0.8 in the Feasible molding window.

    8.2. Set the injection pressure factor to 0.5 in the Preferred molding window.

    8.3. Set the Flow front temp. Maximum drop to 20C.

    8.4. Set the Flow front temp. rise limit to 2C

    8.5. Click OK to exit advanced options.

    8.6. Click OK to exit the Process Settings Wizard.

    9. Click (File Save Study).10. Click (Start Analysis).

    Table 1: Molding conditions notes

    Parameter ValueBox Mold temperature range analyzedBox Melt temperature range analyzedBox Injection time range analyzedLid Injection time range analyzedCombined injection time range to analyze16 Chapter 2

  • To run a molding window analysis for the lid

    1. Repeat the steps in the previous task for the lid model.

    To find one set of process conditions that work for both parts1. Ensure that both the Box MW2 and Lid MW2 studies are open.

    Close any additional windows.2. Click Window Tile Vertically.

    3. Click (View Lock All plots) so results in both studies can be manipulated at the same time.

    4. Click the Molding window:2D Slice Plot in the study tasks list.

    5. Click (Results Plot Properties) for the molding window plot.5.1. Set the cut axis to Mold Temperature.

    5.2. Set the Cut position to 40C.

    h A 40C mold temperature is a reasonable temperature for both parts.5.3. Click OK.

    6. Examine the molding window plots for both the box and lid.

    The X-axis for melt temperature is the same. The Y-axis for injection time is the same because the time range was specified in

    the analysis. If the analysis was left on automatic, the time range would be different. Getting the same range analyzed is the reason the molding window was run twice.

    The green area represents preferred conditions for the part. The size of the preferred windows is different, and dont overlap much with the time range.

    7. Click (Examine Results) at 240C, as this is a mid range temperature for the box.

    Find 0.7 seconds on both parts. Notice how this time is on the fast side for the box, and on the slow side for the lid, but it works for both.

    The molding conditions to be used for both parts are:

    To run a fill analysis on the box1. Ensure the Box MW2 study open and active.

    2. Double-click (Analysis Set Analysis Sequence) and select Fill. 3. Click Create a Copy, when prompted.

    Mold Temperature 40 CMelt Temperature 240CInjection Time 0.7 sec.Practice - Family Tools 17

  • 4. Name the new study Box Fill.5. Double-click (Process Settings Wizard) and enter the following conditions.

    6. Double-click (Start Analysis).

    To run a fill analysis on the lid1. Ensure the Lid MW2 study open and active.

    2. Double-click (Analysis Set Analysis Sequence) and select Fill. 3. Click Create a Copy, when prompted.

    4. Name the new study Lid Fill.

    5. Double-click (Process Settings Wizard) and enter the following conditions.

    6. Double-click (Start Analysis).

    To review results1. Ensure both the Box Fill and Lid Fill studies are open and all other studies are

    closed.

    2. Click Windows Tile Vertically.

    3. Click (View Lock All plots). Results in both studies will be displayed and manipulated at the same time.

    4. Rotate, pan, or zoom each part as necessary to get a good view.

    5. Plot the following results:

    Fill time. Pressure at V/P switchover. Bulk temperature.5.1. Animate the results as necessary.

    5.2. Ensure all the results are acceptable.

    Mold Temperature 60 CMelt Temperature 245CInjection Time. 0.7 sec.

    Mold Temperature 60 CMelt Temperature 245CInjection Time. 0.7 sec.18 Chapter 2

  • To determine the volume of the box and lid

    1. Click Box Fill to activate it.

    2. Click MeshMesh Statistics.3. Record box volume in Table 2.

    4. Click Lid Fill to activate it.

    5. Click MeshMesh Statistics.6. Record Lid volume in Table 2.

    7. Add the part volumes together and record it in Table 2.

    Building the family tool model

    To add the box and lid models together1. Activate the Box Fill study.

    2. Click (File Save study as).2.1. Enter the name Box Lid.

    3. Click (File Add).4. Select the study Lid Fill and click Open.

    Table 2: Volumes

    Component VolumeBox Lid Sum of parts

    3 The Box and Lid models were imported into Synergy in tool position. When the Lid was added to the Box model they were automatically in the correct location.

    / It is best to put the parts of the family mold in tool position before they are added together.Practice - Family Tools 19

  • To build the runner system

    1. Ensure the Box Lid study is open and active.

    2. Click Modeling Runner System Wizard.2.1. Create the runner system for the box and lid, using the dimensions shown in

    Figure 3.

    2.2. Create the runners with a circular cross section that is equal to the height of the runner.

    h The runner balance analysis only sizes round runners. h The runners can be converted to trapezoidal after the balance.

    Figure 3: Runner drawing

    The drops in the runner system are set to unconstrained. Tapered features of the feed system should not be changed during a runner balance. To prevent the change, the drops are going to be changed from a runner to gate property.

    Constraining the dropsThe drops between the part and main runner are tapered, and should not be sized during the balance. The Runner creation wizard created the drops with a cold runner property. If nothing was changed, the drops would be sized during the balance. To prevent the drops from being sized during the balanced one of two things can be done:

    The runner sizes can be fixed to their current size. The runner property can be changed to a gate property.The runner balance algorithm will not size properties of a Sprue or Gate. Only runners are changed. For this example, the property of the drops will be changed to Gate.20 Chapter 2

  • To fix the drop dimensions

    1. Select all the elements in either one of the tapered drops, as shown in Figure 4.

    2. Right-Click and select Change Property type from the context menu.

    3. Select Cold gate on the Change Property Type To dialog.

    4. Click OK twice accept the change.

    5. Repeat the process for the other drop.

    Figure 4: Selecting elements to change the properties

    Analyzing the tool

    A flow rate should be used as the filling control. This will ensure the parts will fill in the time determined as optimum.

    To calculate the flow rate1. Recall the total flow rate from both cavities that you have recorded in Table 2.

    2. Divide this by the injection time used to fill the parts, which is 0.7 seconds.

    3. Record the flow rate below.

    To run a Flow analysis1. Ensure the Box Lid study is open.

    2. Double-click (Process Settings Wizard).

    3. Set Filling Control to Flow Rate.

    4. Enter the flow rate you calculated above.

    5. Set the Fill/Pack switch-over to by % volume filled at 100%.

    6. Set the Pack/holding control Profile Settings to % Filling pressure to 100%.

    This study will be duplicated for runner balancing, which works better when the pressure does not drop after the switch-over. Once the runners are balanced, you may set the switch-over to the desired value.

    Band Select

    Flow Rate = cc/sec.Practice - Family Tools 21

  • 7. Click OK twice.8. Double-click (Start Analysis).

    To review results to determine balance inputs1. Plot Fill Time.

    2. Click (Animate result).

    3. Step the animation from the start of fill until the Lid is just full.

    Note how much there is left to fill on the Box.4. Plot the Pressure.

    Pressure is very sensitive to the runner balance. Notice how the pressure of the lid is very high compared to the box.

    5. Plot the Pressure at injection location.

    This is an XY plot of the pressure gradient at the injection location. The pressure spike at about 0.7 seconds corresponds to the lid filling and the box

    has yet to fill out. See Figure 5.

    In this case, the balance pressure that will be used is 58 MPa which is slightly above the pressure at the end of fill.

    Figure 5: Pressure XY graph at the injection location

    To balance the runners1. Double-click the Analysis Sequence icon in the Study Tasks pane.

    2. Select Runner Balance.

    3. Click OK.

    If Runner balance is not in the list, click the More button and choose runner balance from the full list of analysis sequences.

    / The higher the balance pressure, the smaller the runner diameters will be which will save material. However if the runner diameters are too small, the parts with the small runner may not pack out properly.22 Chapter 2

  • 4. Double-click the Process Settings icon in the Study Tasks pane.4.1. Ensure the filling parameters are correct.

    4.2. Click Next.

    4.3. Set the target pressure to 60 MPa.

    4.4. Click Advanced Options.

    4.5. Set the Mill Tolerance to 0.1 mm

    4.6. Click OK.

    4.7. Click Finish.

    5. Double-click (Continue analysis).

    Review the results

    To view the Analysis Log results1. Open the Analysis Log if necessary.

    2. Watch the analysis progress or review it when the analysis is done.

    3. Review the iteration table.

    The last iteration should be below all three tolerances. If it reached the iteration limit, one more analysis is run with the iteration that

    had the lowest time imbalance.

    To review volume change1. Click on the Volume change result in the Box Lid study.

    2. Notice the distribution of volume change.

    Only the runners have results, because this was the only thing that could change. The percent change will be zero if the runner size is fixed. A negative volume change indicates the runner got smaller, and is generally

    preferred.

    A positive volume change indicates the runner has gotten larger and in generally an indication that the balance (target) pressure is too low.

    To view the thickness changes1. Double-click on the Box Lid (Runner Balance) study to open it.

    2. Rotate the model as necessary to see the runners and parts. A good rotation is -70 -25 -10.Practice - Family Tools 23

  • 3. Plot the thickness diagnostic.

    3.1. Click the Tools tab.3.2. Click (Mesh Diagnostic).

    3.3. Select Thickness Diagnostic.

    3.4. Click Show.

    4. Click (Examine result).

    5. Click on the runners.

    Notice how both are less than 6 mm, (the original sizes), hence the negative volume in the volume change plot.

    To plot fill time1. Click the Fill time result.

    2. Click (Animate).

    Notice how the flow fronts are very balanced compared to the first analysis.

    To plot pressure1. Click the Pressure at V/P switchover result.

    Notice how the Box fills last.

    2. Click (Examine result).

    3. Click on the parting line of the lid.

    Notice that the pressure is just above zero, while there is a noticeable portion of the box not filled yet.

    To review other results1. Plot other results to see the influence of the balance.

    2. If desired, tile the windows and lock the studies:

    Box Lid. Box Lid (Runner Balance).

    3. Compare the filling results between the two analyses.

    Finishing upIf the balance results are acceptable, possibly the runner dimensions can be rounded. Any changes in runner diameter from the optimum will influence the balance. If the sized runners are close to a standard size, rounding may be acceptable. Any rounding that is done should be validated using a Fill + Pack analysis to check the balance but also volumetric shrinkage.24 Chapter 2

  • Competency check - Family Tools1. What is the ideal scenario when creating family molds, with regards to part volume?

    2. List the main steps to optimize a family mold

    3. How does the procedure to analyze family molds differ from analyzing multi-cavity tools?Practice - Family Tools 25

  • 26 Chapter 2

  • Evaluation Sheet - Family Tools1. What is the ideal scenario when creating family molds, with regards to part volume?

    The volume of the parts in the family tool should be close together. When one part is many times larger than another, the balance becomes difficult and the molding window gets small.

    2. List the main steps to optimize a family mold

    Moldflow recommends following the steps listed below:1) Use the Molding Window analysis to find the same processing conditions that works for each one of the parts.

    2) Run a Fill analysis to verify the process settings, optimize the part filling and find the volumes of the parts.

    3) Add all the parts to one study file and create the runner system.

    4) Balance the runners with the runner balance analysis, manually or a combination.

    3. How does the procedure to analyze family molds differ from analyzing multi-cavity tools?

    There are multiple parts of different volumes and pressures to fill. There must be one set of processing conditions found that fills each one of the parts. When the variation in part size becomes large, the molding window may get quite small.Practice - Family Tools 27

  • 28 Chapter 2

  • CHAPTER 3Multiple Gates

    Aim

    The aim of this chapter is to determine the optimum number and location of gates to make the part fill evenly and with an acceptable pressure.

    Why do it

    Two or more gates per cavity are sometimes required for large products where the flow distances from a single gate would be too long, or one gate cannot produce a balanced filling pattern. Finally multiple gates can be used to move weld lines.

    Overview

    In this chapter, you will look at the issues involved with using multiple gates on parts. There are two types of problems related to multiple gates: symmetrical and non-symmetrical part geometries. With a symmetrical gating location, the flow length and pressure drop and volume from each gate is about the same. With non-symmetric gate locations, the flow length, pressure and flow length is not the same. In both cases, the runners need to be balanced by changing the runner diameter to provide the correct volume to each gate so the filling pattern will be balanced.

    This chapter will use the Molding Window analysis and the fast analysis as an aid for solving the problem. In this chapter you will also learn how to work with clamp tonnage.Multiple Gates 29

  • 30 Chapter 3

  • Practice - Multiple GatesThis chapter has several models that are used for practice and are described below. Proceed with the model of your choice. Do the others as time permits.

    Table 3: Models used for molding window analysis

    Description ModelDrawer: starts on page 33

    The drawer model, or chest of drawers, has three gates on the front face of the part. The gate locations are fixed. The main objective is to balance the hot runners to fill the part with a balanced filling pattern.

    Door panel: starts on page 45The door panel will require multiple gates. You must determine the gate locations and construct and balance the runners. You will have a clamp tonnage limitation for this part as well.Practice - Multiple Gates 31

  • 32 Chapter 3

  • Drawer ModelDesign criteriaThe drawer will be made with a 2-plate tool using a hot runner system. Figure 6 indicates the position of the gates. The material is a high-density polyethylene. You will determine the optimum processing conditions, size, and balance the hot drops accordingly.

    Figure 6: Drawer with injection locations

    For the drawer model, you will perform the following:

    Run a molding window analysis with the provided gate locations. Run a filling analysis at the optimum processing conditions. Review filling results. Create a hot runner system using the runner creation wizard. Run a fill analysis with the runners. Evaluate flow balance. Change drop diameters to improve the balance as necessary. Re-run and review results.

    Project setup

    To open a project1. Click (File Open Project) and navigate to the folder

    My AMI 2010 Projects\AMI Standard 1\Multiple_Gates.

    2. Double click the project file Multiple_Gates.mpi.Practice - Multiple Gates 33

  • 3. Click File Preferences.3.1. Ensure the active units are set to metric units.3.2. Click on the Directories tab.

    3.3. Ensure the Default to project directory box is checked.

    By having the box checked, the import dialog will open in the project directory.

    To review the model1. Open the model Drawer.

    2. Investigate the model geometry using the model manipulation tools.

    3. Turn on the default layer to see the injection locations.

    Determine molding conditions

    To analyze the molding window1. Double-click (Analysis Set Analysis Sequence) and select Molding

    Window.

    2. Select the material BASF, Polystyrol 165 H.

    3. Double click (Analysis Process Settings). 3.1. Click the Edit button in the Injection molding machine frame.

    h Click the Hydraulic Unit tab.h Set the maximum machine injection pressure to 140 MPa.h Click OK to exit the dialog.

    3.2. Click the Advanced options button.

    h Set the Pressure factor to 0.8 in the Feasible molding window.h Set the Pressure factor to 0.5 in the Preferred molding windowh Set the Flow front temp. Maximum drop to 20C.h Set the Flow front temp. Maximum rise to 2C.h Click OK to exit Advanced options.

    3.3. Click OK to exit the Process Settings Wizard.

    4. Click (File Save Study).5. Click (Start Analysis).

    6. Follow the General Interpretation Procedure below to interpret the results and determine your processing conditions.

    7. Record the processing conditions you choose in Table 4 on page 40.34 Chapter 3

  • Molding window general interpretation procedure

    The procedure for looking at molding window results will vary, depending on the objectives of the analysis. The basic procedure is as follows:

    1. View the Analysis Log.

    1.1. Find the recommended processing conditions near the bottom of the Analysis Log, as shown in Figure 7.

    1.2. Compare the recommended conditions of mold and melt temperature to the ranges near the top of the Analysis log.

    h The recommended conditions should preferably be near the middle of the ranges.

    h If not, this would indicate you might need to investigate choosing conditions other than the recommended conditions.

    Figure 7: Molding window Analysis Log

    Analysis commenced at Wed Jul 09 09:15:31 2008Analysis has detected a mesh change since initial mesh generation ... recalculating mesh match and thickness information Processing Dual Domain mesh...Computing match using the maximal-sphere algorithm... finished processing Dual Domain mesh Mold temperature range to analyze = Automatic from mold temperature = 80.0 C to mold temperature = 95.0 C Melt temperature range to analyze = Automatic from melt temperature = 270.0 C to melt temperature = 295.0 C Injection time range to analyze = Automatic Limits for calculation of feasible molding window Shear rate limit = Off Shear stress limit = Off Flow front temperature drop limit = Off Flow front temperature rise limit = Off Injection pressure limit factor = 0.80 Clamp force limit = Off Limits for calculation of preferred molding window Shear rate limit factor = 1.00 Shear stress limit factor = 1.00 Flow front temperature drop limit = 20.00 C Flow front temperature rise limit = 2.00 C Injection pressure limit factor = 0.50 Clamp force limit factor = 0.80Maximum Design Clamp Force 7000.22 tonneMaximum Design Injection Pressure : 180.00 MPaRecommended Mold Temperature : 91.67 CRecommended Melt Temperature : 295.00 CRecommended Injection Time : 0.4612 s Execution time Analysis commenced at Wed Jul 09 09:15:31 2008 Analysis completed at Wed Jul 09 09:15:35 2008 CPU time used 3.88 sPractice - Multiple Gates 35

  • 2. View the Molding window 2D Slice Plot.

    The molding window plot shows a 2D shaded graph. It uses mold temperature,

    melt temperature and injection time. Two of the 3 variables form the axis of the graph, the other is the Cut axis for the graph. The best cut axis is mold temperature. When the cut axis is mold temperature, the X-axis is melt temperature, and the Y-axis is injection time, as shown in Figure 8.

    The cut axis can be animated with (Add XY Curve). Hold the left mouse button down and drag the mouse up and down.

    The molding window plot will give you a sense for the size of the molding window. The plot uses 3 colors:

    h Green - represents an area that is within the preferred molding window.h Yellow - represents the size of the feasible molding window. This would

    mean that one of the parameters of the preferred window is outside the limit. More than likely it is a temperature limit.

    h Red indicates the pressure is higher than the factor set for the feasible molding window.

    Figure 8: Molding window plot showing the size of the molding window36 Chapter 3

  • 2.1. Set the cut axis to Mold temperature in the plot properties.2.2. Use (Add XY Curve) to animate the molding window plot. Determine how much the mold temperature influences the size of the molding window.

    h Generally, as the mold temperature goes up, the size of the molding window increases but typically not by much.

    h Most of the time the mold temperature specified in the analysis log file is near the high end of the range. If there is little change in the size of the molding window, a midrange mold temperature can be used.

    2.3. Set the mold temperature cut axis value to the mold temperature you want to use.

    2.4. Use (Examine result) on the molding window plot to find the injection time and melt temperature found in the analysis log.

    h Ideally, the chosen conditions are near the middle of a large preferred window. If not, use the examine result tool to find the melt temperature and injection time that are near the size of the molding window.

    h Decide on the mold temperature, melt temperature, and injection time that you want to use. These will be the optimum conditions. You will look at other results at these conditions to confirm you like the optimum conditions or if you would like to modify them.

    3. Check the Pressure drop, maximum (molding window) XY Plot.

    3.1. Set the X-axis to be injection time, using the plot properties, shown in Figure 9, slide the optimum mold and melt temperature to the values determined in the molding window plot.

    3.2. Use the examine result tool to find the optimum injection time on the pressure curve.

    h This represents the pressure required for the optimum conditions. See Figure 10 on page 38.

    3.3. Make sure the pressure is under the 70 MPa (10,000 psi) guideline, or about half the machine injection capacity. With the proper molding machine settings, and Advanced options settings, the green area of the zone plot will be under half of the machines pressure capacity

    3 The molding window plot is most meaningful if the machine pressure capacity is known and the pressure factors for the feasible and preferred windows are set.Practice - Multiple Gates 37

  • Figure 9: Molding window, explore solution space - plot properties

    Figure 10: Pressure drop XY graph

    4. Check the Temperature at flow front, minimum (molding window) XY Plot.

    4.1. Set the X-axis to be injection time, using the plot properties slide the mold and melt temperature to the optimum conditions.

    4.2. Use the examine results tool to find the optimum injection time.

    h The best injection time will be when the flow front temperature is about equal to the melt temperature.38 Chapter 3

  • 4.3. Use the examine results tool to find where the temperature is 0 C, 10 C. (18 F), and 20 C. (36 F) below the melt temperature. See Figure 11 on page 39h A 0 C drop in temperature defines the highest quality. h A 10 C (18 F) drop in temperature in most cases is a very acceptable

    amount of drop.

    h A 20 C (36 F) defines the limit of the preferred molding window, assuming it was set a maximum temperature drop of 20C (36F) in the advanced options.

    h Finding at what times these temperatures occur will give you another way to get a sense for the size of the molding window as the flow front temperature is generally the limiting factor in the molding window.

    Figure 11: Minimum flow front temperature graph

    5. Check the Maximum Shear Stress XY Plot.

    5.1. Set the X-axis to be injection time, using the plot properties, and slide the mold and melt temperature to the new conditions.

    5.2. Make sure the shear stress is below the material limit.

    h The lower the shear stress, the better. h Typically, the maximum shear stress plotted in this result will be significantly

    higher than the nominal shear stress in the part. If the shear stress is near or above the limit for this plot, you should concentrate on the shear stress result when you run a fill or pack analysis. You should find that the majority of the part has acceptable levels of stress and there may be some limited areas of high stress.

    / Up to four XY plots can be viewed and manipulated at the same time. Split the screen into 2 or 4 windows. Plot in each of the windows a different XY graph. For one of the graphs, open the plot properties. On the Explore Solution Space XY Plot dialog, check the Lock all molding window XY plots in this study box. Now as you manipulate the sliders, all windows will update accordantly.Practice - Multiple Gates 39

  • 6. Check remaining plots.

    6.1. Cooling time h The cooling time is viewed to see what effect processing conditions have on the cooling time. Mold temperature generally has the greatest influence so that should be the X axis.

    6.2. Shear Rate

    h The shear rate will never be excessive in your part as a whole. There may be some very local areas where the shear rate approaches the limit. Plotting the shear rate from a molding window analysis will show you how the shear rate drops with the increase of the injection time.

    The quality plot

    The molding window analysis determines the recommended processing conditions, found in the analysis log, based on the set of conditions that has the highest quality. The quality is calculated using the parameters in the advanced options described earlier. The maximum quality possible is 1.0. Generally the maximum values for a given part are between 0.8 and 0.95. There will be many combinations of mold temperature, melt temperature, and injection time that will have quality values close to the recommended processing conditions. The Molding window plot easily shows this by the size of the green area. It is useful to view the quality plot to understand how the recommended conditions are picked, but the Molding window 2D Slice plot is the best plot to determine the optimum conditions and then use others to confirm the conditions.

    To view the quality plot:

    1. View the quality plot and set the X-axis of the graph to be injection time using the plot properties, as indicated in Figure 9 on page 38.

    2. Adjust the mold and melt temperature sliders to the recommended mold and melt temperatures found in the Analysis Log.

    Normally, the data point with the highest quality is easy to visualize, as there is a sharp drop in quality from the maximum.

    3. Use the Examine results tool to find the injection time of the data point with the highest quality. It will be the recommended injection time in the log file.

    Run the first fill analysisThis is to verify the processing conditions used when the runner system is added.

    Table 4: Drawer Processing Conditions used

    Parameter ValueMold TemperatureMelt TemperatureInjection Time40 Chapter 3

  • To run a filling analysis

    1. Click (File Save Study as) and name the study Drawer fill.2. Set the analysis sequence to Fill.

    3. Enter the process settings that you determined from the molding window analysis.

    4. Double-click (Start Analysis!).

    To review the results1. Plot the Fill time plot.

    Ensure the filling is balanced between the 3 gates.2. Check the Pressure at V/P Switchover.

    Make sure the pressure is less than 70 MPa.3. Check the Bulk Temperature.

    The range of temperatures should be less than 20 C.4. Check the Shear stress at wall plot.

    Make sure the shear stress is not too high.5. Check other plots as necessary.

    6. Change some inputs and re-run the analysis if you are not satisfied with the results.

    Create the hot runner system

    To prepare for creating the runner system1. Click (File Save Study).

    2. Click (File Save Study as) and name the study DrawerRun1.

    To create a hot runner1. Click Modeling Runner System Wizard.2. Select Center of gates, for the position of the sprue.

    3. Click the I would like to use a hot runner system box.

    4. Set the Top runner plane Z, for the location of the manifold per the drawing in Figure 13.

    5. Set the sprue, runner and drop sizes per the drawing in Figure 13.

    6. Set the gate size per the drawing in Figure 12.Practice - Multiple Gates 41

  • Figure 12: Drawer gate detail

    Figure 13: Drawer drawing

    To run a fill analysis with the runners1. Click (File Save Study).2. Ensure the process settings are correct.

    3. Click (Start Analysis).

    To review the results1. Plot Fill time.

    1.1. Open Plot properties.

    1.2. Change the Method to Contour.42 Chapter 3

  • 2. Decide if you think the filling is balanced enough.

    3. Plot Pressure at V/P Switchover. Notice how the center of the sides has filled out, and the areas left to fill are on the outside corners. This is an indication that the balance could be better. The center is filling too fast. The top is also filling faster than the bottom.

    The size of the top drop will be reduced to 7 mm and the center drop will be reduced to 5 mm to help create a better balance.

    To revise the results1. Click (File Save Study).

    2. Click (File Save Study as) and name the study DrawerRun2.

    3. Click (Bottom View)

    4. Change the center drop.

    4.1. Select all of the elements in the center drop. Refer to Figure 14.

    4.2. Click (Edit Assign Property).4.3. If prompted, select Beam element as the entity type and click OK.

    4.4. Click New.

    4.5. Select Hot runner to create a new hot runner property with:

    h A non-tapered circular shape.h A diameter of 5.0 mm.h Change the name to 5 mm drop.

    5. Change the top drop. Refer to Figure 14.

    5.1. Select the elements in the top drop.

    5.2. Click (Edit Assign Property).5.3. If prompted, select Beam element as the entity type and click OK.

    5.4. Click New.

    5.5. Select Hot runner to create a new hot runner property with:

    5.6. Create a new hot runner property with:

    h A non-tapered circular shape.h A diameter of 7.0 mm.h Change the name to 7 mm drop.

    6. Click (File Save Study).7. Click (Start Analysis).Practice - Multiple Gates 43

  • Figure 14: Drawer drop locations

    To review the results1. Plot the Fill time plot.

    1.1. Click (Plot properties).

    1.2. On the Methods tab, change the selection to Contour.

    Now you can see that the balance is better.1.3. Open the DrawerRun1 study, and tile the results to compare them if desired.

    2. Plot the Pressure at V/P Switchover.

    The Switchover is just early enough to see that the part is a bit more balanced.

    SummaryReducing the center and top drops made the balance a bit better. To further improve the balance, the wall thickness on the part will need to be adjusted. The top of the part needs a flow deflector so the center of the top does not fill out so early. Also the bottom could be increased in thickness slightly to encourage flow in that direction.

    Top drop Center drop Bottom drop44 Chapter 3

  • Door PanelDesign CriteriaThe door panel is constructed with a 2-plate tool using a hot runner system. The tool is constructed with the underside of the part on the cavity side of the tool so it can be gated on that side. The tool will have cavity side ejection.

    The tool will go in a 1500 tonne press. The design clamp limit will be 1200 tonnes or 80% of the press capacity.

    The number and location of gates, plus the processing conditions are to be determined.

    There should be as few weld lines as possible. There must be no air traps in areas that are difficult or impossible to vent. The hot runner system must be sized and balanced so the filling pattern from the

    gate locations is balanced.

    Figure 15: Door panel model

    Figure 16: Door panel side view

    PLUndersidePractice - Multiple Gates 45

  • Analysis procedure

    For the door panel model you will perform the following:

    Iterate between the gate location analysis and molding window analysis to determine the number and general location of the gates, in order to keep the fill pressure below 50% of the machines capacity.

    Run a filling analysis at the optimum processing conditions and gate locations determined.

    Review filling results. Revise the gate location(s) as necessary to get a good balanced filling pattern within

    the 1200 tonne clamp tonnage design limit.

    Create a hot runner system using the chosen gate locations. Run a fill analysis with the runners. Evaluate the filling. Change drop diameters in to improve balance as necessary. Re-run and review results.

    Project setup

    To open a project1. Click (File Open Project) and navigate to the folder

    My AMI 2010 Projects\AMI Standard 1\Multiple_Gates.

    2. Double click the project file Multiple_Gates.mpi.

    3. Click File Preferences.3.1. Ensure the active units are set to metric units.

    3.2. Click on the Directories tab.

    3.3. Ensure the Default to project directory box is checked.

    By having the box checked, the import dialog will open in the project directory.

    To review the model1. Open the model Door Panel.

    2. Investigate the model geometry using the model manipulation tools.

    The clamp tonnage limit must be set for the initial study so all studies created after this point will have the correct clamp tonnage.

    To set the clamp tonnage limit1. Click the Process Setting Wizard.

    2. Click the Advanced Options button.

    3. Click the Edit button next to the Injection molding machine box.46 Chapter 3

  • 4. Click the Clamping Unit tab.

    5. Enter 1200 in the Maximum machine clamp force field.6. Ensure the Do not exceed maximum clamp force box is checked.

    7. Click OK 3 times to get out of the dialogs.

    8. Click (File Save Study).

    Selecting gate locations and molding conditionsUsing the gate location analysis is a good way to get started for determining the gate location for the door panel. The gate location(s) for the door panel can be anywhere on the underside of the door panel.

    To run an initial gate location analysis1. Click (File Save Study as) as Door Panel Gate Loc 1.2. Set the analysis sequence to Gate Location.

    3. Select the material Kralastic SXB-367, an ABS from Sumitomo Chemical Company.

    4. Click and ensure the Advanced gate locator is used and the number of gates is set to one.

    5. Click OK to exit the wizard.

    6. Click to run the analysis.

    To view the gate location results1. Click the Flow resistance indicator result.

    Notice how the gate location is near the arm rest. The analysis calculates the location to minimize the pressure, but you have no idea what this pressure is.

    To run a molding window analysis at the chosen gate location1. Right-click on the study Door Panel Gate Loc 1(Gate Location).

    2. Select Rename and enter Door Panel Gate Loc 1 MW.

    3. Double-click (Analysis Set Analysis Sequence) and select Molding Window.Practice - Multiple Gates 47

  • 4. Double click (Process Settings).4.1. Click the Edit button in the Injection molding machine frame.

    h Click the Hydraulic Unit tab.h Set the maximum machine injection pressure to 140 MPa.h Click OK to exit the dialog.

    4.2. Click the Advanced options button.

    h Set the Pressure factor to 0.8 in the Feasible molding window.h Set the Pressure factor to 0.5 in the Preferred molding windowh Set the Flow front temp. Maximum drop to 20C.h Set the Flow front temp. Maximum rise to 2C.h Click OK to exit Advanced options.

    4.3. Click OK to exit the Process Settings Wizard.

    5. Click (File Save Study).6. Click (Start Analysis).

    7. Follow the Molding window general interpretation procedure on page 35 to interpret the results and determine your processing conditions.

    The molding window analysis does not output any results that indicate clamp force changes with processing conditions. However, if the pressure to fill is limited, so will the clamp force.

    8. If you dont like the molding window results, revise the gate location(s) and re-run the analysis. You can pick your own gate locations, or use the gate location analysis to help you pick more gates.

    9. Record the processing conditions you select in Table 5.

    Optimize the fillingNow that the gate location(s) and molding conditions have been found you need to run a fill analysis to see how the part actually fills and what the clamp force is.

    / In extreme cases, there will be no molding window and an warning message indicating there is none. The cause of the error would be the pressure or clamp force being too high. The pressure to fill must be lowered by reducing the maximum flow length by moving the gate or adding gates.

    Table 5: Truck Panel Initial Processing Conditions

    Parameter ValueMold TemperatureMelt TemperatureInjection Time48 Chapter 3

  • To run a filling analysis

    1. Ensure the Door Panel MW1 is active and click (File Save Study as) and

    name it to Door Panel Fill 1.

    2. Double-click and set the analysis sequence to Fill.

    3. Click Tools Play macro (optional).3.1. Navigate to the My AMI 2010 Projects\scripts folder.

    3.2. Highlight the script MP Intermediate results defining.vbs.

    h If you cant find the script, ask your instructor about it.3.3. Select Edit to open the script in a text editor.

    h This script intermediate results at specific times during the filling and packing phases, at 0.2 seconds during filling and 1 second during packing. A portion of the script is shown in Figure 17. The full list of result times was omitted to save space.

    3.4. Close the editor when done reviewing the script.

    3.5. Click Open to play the script and define the intermediate results.

    4. Double click (Process settings wizard).

    5. Enter the process settings that you determined from the Molding Window Analysis.

    6. Click Advanced options.

    6.1. Click Edit in the Injection molding machine frame.

    6.2. Click the Clamping Unit tab.

    6.3. Ensure the clamp force is set to 1200 tonnes.

    6.4. Click OK.

    6.5. Click Edit in the Solver parameters frame.

    6.6. Click the Intermediate Output tab.

    6.7. Ensure the filling phase and packing phase regular results have Write at specified times selected, and the times are set as they were in the vbs script.

    6.8. Exit from advanced options.

    7. Click OK on the Process Setting Wizard dialog.

    8. Double-click (Start Analysis).Practice - Multiple Gates 49

  • Figure 17: Example vbs script for setting the intermediate results

    To review the results1. Open the Analysis Log and view the filling phase results table.

    This will show when the clamp tonnage limit was reached and how the pressure and flow rate changed because of the clamp tonnage limit.

    See Figure 18 as an example. Preferably, the clamp tonnage should not be reached. If it is, the later the better.

    2. Display Fill time.

    2.1. Animate the result to time closest to the time when the clamp force was reached.

    h There is a significant amount of the part yet to fill when the clamp force was reached.

    3. Plot Pressure.

    3.1. Animate the result to time step closest to the time when the clamp force was reached.

    h The clamp force limit was reached so early, there is not much overpacking.

    Set Synergy = CreateObject("synergy.Synergy")Synergy.SetUnits "Metric"Set PropEd = Synergy.PropertyEditor()Set Prop = PropEd.FindProperty(10000, 1) '10000 = midplane,10005 =DDSet DVec = Synergy.CreateDoubleArray()DVec.AddDouble 0.2DVec.AddDouble 0.4..DVec.AddDouble 4.6DVec.AddDouble 4.8DVec.AddDouble 5Prop.FieldValues 180, DVec '180 = Write filling phase regular results at timesSet DVec = Synergy.CreateDoubleArray()DVec.AddDouble 6DVec.AddDouble 7DVec.AddDouble 8..DVec.AddDouble 25Prop.FieldValues 182, DVec '182 = Write Packing phase regular results at timesSet DVec = Synergy.CreateDoubleArray()DVec.AddDouble 2DVec.AddDouble 0Prop.FieldValues 198, DVec '198 = filling phase, write results 2 = specified timesSet DVec = Synergy.CreateDoubleArray()DVec.AddDouble 2DVec.AddDouble 0Prop.FieldValues 199, DVec ' 199 = Packing phase, write results 2 = specified timesPropEd.CommitChanges "Process Conditions"50 Chapter 3

  • Figure 18: Analysis log filling phase table

    Fill AnalysisResidual Stress Analysisanalysis is beginning .... Filling phase: Status: V = Velocity control P = Pressure control V/P= Velocity/pressure switch-over|-------------------------------------------------------------|| Time | Volume| Pressure | Clamp force|Flow rate|Status || (s) | (%) | (MPa) | (tonne) |(cm^3/s) | ||-------------------------------------------------------------|| 0.20 | 3.38 | 8.40 | 4.04 | 565.16 | V || 0.40 | 8.00 | 12.23 | 13.92 | 577.29 | V || 0.60 | 12.71 | 15.01 | 28.11 | 588.28 | V || 0.80 | 17.46 | 17.44 | 47.78 | 590.90 | V || 1.00 | 22.23 | 19.68 | 72.17 | 592.31 | V || 1.20 | 27.01 | 21.72 | 99.69 | 595.33 | V || 1.40 | 31.79 | 23.69 | 131.95 | 597.53 | V || 1.60 | 36.58 | 25.58 | 167.75 | 599.74 | V || 1.80 | 41.37 | 27.39 | 207.58 | 601.17 | V || 2.00 | 46.14 | 29.46 | 262.30 | 600.19 | V || 2.20 | 50.90 | 31.63 | 325.78 | 601.52 | V || 2.40 | 55.66 | 33.71 | 393.19 | 603.12 | V || 2.60 | 60.43 | 35.76 | 466.92 | 603.78 | V || 2.80 | 65.19 | 37.79 | 546.36 | 604.67 | V || 3.00 | 69.96 | 39.78 | 629.40 | 605.92 | V || 3.20 | 74.69 | 42.28 | 748.42 | 605.68 | V || 3.40 | 79.42 | 44.87 | 877.96 | 607.07 | V || 3.60 | 84.14 | 47.52 | 1020.84 | 607.85 | V | ** WARNING 98932 ** The clamp force required to fill/pack the part is greater than the maximum machine clamp force value in the clamping unit properties of the currently selected injection molding machine. The maximum machine clamp force will be maintained in the analysis.| 3.80 | 88.80 | 50.94 | 1200.00 | 608.69 | V || 3.90 | 90.87 | 45.25 | 1200.00 | 393.37 | V || 4.00 | 92.22 | 42.70 | 1200.00 | 310.89 | V || 4.10 | 93.35 | 41.59 | 1200.00 | 266.00 | V || 4.20 | 94.32 | 40.79 | 1200.00 | 234.56 | V || 4.30 | 95.16 | 40.07 | 1200.00 | 205.20 | V || 4.40 | 95.85 | 36.33 | 1200.00 | 133.50 | V || 4.60 | 96.54 | 32.76 | 1200.00 | 86.95 | V || 4.80 | 97.05 | 32.34 | 1200.00 | 73.25 | V || 5.00 | 97.47 | 32.38 | 1200.00 | 65.13 | V || 5.93 | 98.61 | 29.77 | 1200.00 | 27.60 | V/P |** WARNING 128272 ** Short shot detected. The clamp force of the injection molding machine is insufficient. ------------------------------------------------------------------------Practice - Multiple Gates 51

  • Results interpretation

    It is clear just from the analysis log that the single gate option will not work. The clamp

    force limit was hit early and a short shot was created. Looking at the fill time and pressure plots you can see that a significant area of the part is at high pressure, causing the spike in clamp force.

    Finalizing the gate locations

    A single gate will not work because the clamp force is too high. Additional gates must be used. Iterate between the gate location analysis, molding window analysis and fill analysis to find and test gate locations. Ensure the gate locations you pick are possible when using a hot runner system on the underside of the part.

    To determine the final gate locations1. Click (File Save All Studies).

    2. Activate the Door Panel Fill 1 study and click (File Save Study as) and name it Door Panel Gate Loc 2.

    3. Run a gate location analysis.

    3.1. Set the analysis sequence to Gate Location.

    3.2. Use the number of gate of your choosing.

    h The fewer gates the better.3.3. Review the gate location results.

    h Ensure the gate locations determined by the gate location analysis are possible with a hot runner.

    3.4. Move the gates if necessary to make it possible to use the locations.

    4. Run a Molding window analysis with the new gate locations.

    With a shorter flow length, the fill time will probably be shorter than with one gate.

    5. Run a fill analysis.

    5.1. Use the new gate locations and molding conditions determined.

    5.2. Ensure the same intermediate results files are selected.

    6. Review the results.

    6.1. Compare the new results with the first filling analysis.

    6.2. Lock the results and tile the windows to look at the results together.

    6.3. Look carefully at the pressure plot. This will indicate how well balanced the filling is. Large areas of high pressure contribute to a spike in clamp force.

    6.4. Decide if the results are reasonable or they still need adjusting.52 Chapter 3

  • 7. Consider one or more of the following changes as needed to get acceptable results.

    Move gate(s) closer to areas that did not fill, or filled later.

    Increase the melt temperature. Decrease the injection time. Add a gate. Use the recommended ram speed profile.

    / Dont stop at one analysis even if you think the results are good. Try to make them better. For instance, a slight variation in gate location can make a large difference in the filling pattern and clamp force requirements. The plot below shows the position of the flow front with 4 subtle variations in the gate location. In all cases, the camp force is exceeded, but at different times and with different reductions in flow rate. The weld line locations also change. To get this plot, The fill time was set with 20 frames, showing the current frame only, the scale was 0 to 4 sec., making the increment 0.2 sec. and banded color was on.Practice - Multiple Gates 53

  • Design and analyze the feed system To create a hot runner1. Click (File Save Study as) on the study with the gate location and

    processing conditions you like, as a new name such as Door Panel Run 1.

    2. Click Modeling Runner System Wizard to create the hot runner.3. On page one of the wizard, enter:

    3.1. Select Center of Mold for placement of the gates.

    3.2. Check the I would like to use a hot runner system box.

    3.3. Enter 400 mm as the top runner plane.

    3.4. Click Next.

    4. On page two of the wizard, enter:

    4.1. Enter 12 mm as the sprue diameter.

    4.2. Enter 0 degrees for the included angle.

    4.3. Enter 25 mm as the sprue length.

    4.4. Enter the size of your choosing for the runner (manifold).

    4.5. Enter the size of your choosing for the drop.

    4.6. Click Next.

    5. On page three of the wizard, enter:

    5.1. Enter the diameters and length of your choosing for the Gates.

    5.2. Click Finish to complete the runner system.

    The hot manifold created by the wizard may not be practical. Consider replacing it. In Figure 19A, the manifold design is not practical. The manifold has extra 90 bends in it going from the sprue to the drops. A manifold like this would not be built. The manifold would be built more like Figure 19B. The manifold goes straight between the drops.

    Figure 19: Manifold curves

    The task below steps through the process of fixing the manifold for the gate locations above. Use these steps to fix your manifold system as needed.

    / Make the manifold diameter larger than the drops.

    A B

    Sprue

    Drops

    12

    3

    454 Chapter 3

  • To revise the runner layout

    1. Rename element properties:

    1.1. Highlight one of the elements in the manifold.

    1.2. Right-click and select Properties.

    1.3. Change the property name to Manifold XX mm, where XX is the diameter of it.

    h Ensure the box Apply to all entities that share this property is checked. h The new name will easily identify this property in the property lists.

    2. Delete the elements.

    2.1. Click Edit Select by Properties or CTRL + B.2.2. Select Beam element and Curve as the entity types.

    2.3. Select the Manifold you renamed property.

    2.4. Click OK.

    2.5. Press the Delete key to delete the elements and curves.

    2.6. Click OK to accept the entity selection.

    2.7. Click Purge Node in the Nodal mesh tools , in the toolbox.

    2.8. Click Apply.

    3. Create a curve for the manifold between drops 2 and 3.

    3.1. Click Create line in the Create curves tools in the toolbox.

    3.2. Set the filter to Node.

    3.3. Select the node at the end of drop 2 as shown in Figure 19B for the First field.

    3.4. Select the node at the end of drop 3 for the Second field.

    3.5. Click Apply.

    4. Click Nodes by Dividing Curve in the Create Nodes tools in the toolbox.

    4.1. Select the curve between drop 2 and 3 just created.

    4.2. Enter 3 in the Number of nodes field.

    4.3. Click Apply.

    5. Create a curve between drop 1 and the curve between drops 2 and 3.

    5.1. Click Create line in the Create curves tools in the toolbox.

    5.2. Select the node at the end of drop 1 as shown in Figure 19B for the First field.

    5.3. Select the node at the center of the curve going between drops 2 and 3, for the Second field.

    5.4. Click Apply.Practice - Multiple Gates 55

  • 6. Make a LCS to help construct the runners.

    6.1. Activate the Runner System layer.6.2. Click Modeling Local Coordinate System/modeling plane Define.6.3. Set the filter to Node.

    6.4. Select the node at the end of drop 1 as shown in Figure 19B for the First field.

    6.5. Select the node at location 4 as shown in Figure 19B for the Second field.

    6.6. Select the node at the base of the sprue for the Third field.

    6.7. Click Apply.

    6.8. Click Close.

    6.9. Select the new LCS.

    6.10.Right-click select Activate as LCS.

    6.11.Click Create line in the Create curves tools in the toolbox.

    6.12.Select the node at the base of the sprue for the First field.

    6.13.Click the Relative radio button.

    6.14.Inter 0 -200 in the Second field.

    6.15.Click Apply.

    7. Break and delete the curves.

    7.1. Click Break Curve in the Create curves tools in the toolbox.

    7.2. Click on the 2 curves shown as break 1 in Figure 20.

    7.3. Click Apply.

    7.4. Click on the 2 curves shown as break 2 in Figure 20.

    7.5. Click Apply.

    7.6. Click Close.

    7.7. Select and delete the node, curve and LCS not needed.

    8. Apply the Manifold property to the new curves.

    9. Mesh the new curves at the same density as the drops.

    Make sure the Runner layer is active and place the new mesh on the active layer.

    Figure 20: Manifold curve construction

    Break 1 Break 2

    Delete56 Chapter 3

  • To check the balance

    1. Run the fill analysis with the same conditions as the study without the runners.

    2. View the Fill time plot.

    Make sure the balance is acceptable.3. View the Weld lines and Air traps.

    Are they still in acceptable locations?4. View the Analysis Log and check for the clamp force limit.

    When is the limit reached? Does the velocity profile change much?

    5. View the Pressure.

    Is the pressure distribution acceptable?If the results are not as balanced as they are in the study without the manifold, the sizes and layout of the hot runner system needs to be adjusted. Either part of the manifold or drops can be changed to fix the problem.

    Different philosophies exist on what to change, and you will need to make this decision. Some prefer to change the manifold, others the drops when there is a choice.

    To re-run the analysis1. Make changes as necessary to improve the balance or to fix some other problem.

    2. Click (File Save Study as) with a new name.3. Re-run the analysis.

    4. Look at the revised results.

    5. Repeat as necessary to get a good result.Practice - Multiple Gates 57

  • 58 Chapter 3

  • Competency check - Multiple Gates1. What are the types of multiple gates scenarios that you may have in the part geometry?

    2. How do you identify a symmetrical multiple gate scenario?

    3. How to identify a non-symmetrical multiple gate scenario?

    4. What are the types of analyses recommended by Moldflow to use to aid in the multiple gates optimization process?Practice - Multiple Gates 59

  • 60 Chapter 3

  • Evaluation Sheet - Multiple Gates1. What are the types of multiple gates scenarios that you may have in the part geometry?

    It can be either symmetrical or non-symmetrical part geometries.

    2. How do you identify a symmetrical multiple gate scenario?

    The part will have symmetrical gate locations. And the flow length and pressure drop from each gate will be about the same.

    3. How to identify a non-symmetrical multiple gate scenario?

    The part will not have symmetrical gate locations. And the flow length and pressure drop from each gate will not be the same, therefore it is more difficult to optimize.

    4. What are the types of analyses recommended by Moldflow to use to aid in the multiple gates optimization process?

    The user should run a set of molding window analysis and fast filling analysis to aid in the number and location of the gates on the part. Then the runner system should be added balanced and further filling and packing analyses should be run to finalize the filling of the part.Practice - Multiple Gates 61

  • 62 Chapter 3

  • CHAPTER 4Packing Optimization

    Aim

    The aim of this chapter is to learn how to produce a uniform volumetric shrinkage through a part with the use of a packing profile. The volumetric shrinkage distribution should be as small as possible.

    Why do it

    When there is a uniform volumetric shrinkage across the part, the likelihood of warpage is reduced. Warpage is simply caused by a variation in shrinkage, therefore, when the shrinkage variation is reduced, so is the warpage.

    Overview

    To create a packing profile, the filling and cooling of the part filling should be optimized first. Packing is influenced by the way a part is cooled; therefore, it is best to produce the packing profile based on cooling results. An initial constant packing profile is run. From this information, an initial packing profile is produced, and then modified as necessary to produce the desired results. This technique will be demonstrated on Dual Domain and 3D models, and can be used with a midplane mesh as well.Packing Optimization 63

  • 64 Chapter 4

  • Practice - Packing OptimizationThis chapter has two models that are used for practice and are described below. One is a Dual Domain model the other is 3D. Do the practice for the model of the mesh type you use most. Do the other as time permits.

    Table 6: Models used for packing optimization

    Description ModelSnap Cover: starts on page 67

    This part uses a Dual Domain mesh. Use this part if your primary mesh type you use is Dual Domain or midplane.

    Snap Cover3: starts on page 85

    This part uses a 3D tetrahedral mesh. Use this part if your primary mesh type you use is 3D.Practice - Packing Optimization 65

  • 66 Chapter 4

  • Snap cover with a Dual Domain meshDesign criteriaThe packing profile for the snap cover must be optimized. The cooling analysis has already been done. The initial processing conditions and criterion are shown in Table 7. Determine a packing profile to minimize the volumetric shrinkage. Review the results on the initial packing analysis and make modifications to the profile will reduce the volumetric shrinkage.

    Project setup

    To open a project1. Click (File Open Project), and navigate to the folder

    My AMI 2010 Projects\AMI Standard 1\Packing_optimization and double click the project file packing_optimization.mpi.

    2. Click File Preferences 2.1. On the General tab, ensure that Active Units are set to Metric.

    2.2. On the Directories tab, ensure Default to project directory is checked.

    To review the model1. Open the study SC Fill.

    This study will be used to determine the initial packing pressure. 2. Investigate the model geometry using the model manipulation tools.

    3. Turn on and off the layers.

    Notice there is several layers for the part itself. These can be used to aid in the interpretation of the results.

    Table 7: Snap cover parameters

    Parameter ValueModel Type Dual DomainMaterial Maplen EP301K (PP)Mold Temperature 25 CMelt Temperature 220 CInjection + Cooling + Packing 15 secondsInjection Time 1.0 secondInitial Packing Pressure 100 % fill pressureInitial Packing Time 9 secondsTarget Maximum Shrinkage Variation

    2% on the body of the partPractice - Packing Optimization 67

  • To run a fill analysis

    1. Double-click (Select Materials) and pick the material Basell Australia,

    Moplen EP301K.

    2. Double-click (Process Settings) and enter the parameters shown in Table 8.

    3. Double-click (Start Analysis).

    Optimizing a packing profileDeveloping an optimized packing profile for a part requires the following basic steps:

    1. Determine an initial packing pressure