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Cooling Analysis Strategies

MOLDFLOW Cooling Analysis Strategies

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Cooling Analysis Strategies

Cooling Analysis Objectives

Cooling analyses are performed to determine (in part)

Cooling line placement Minimum cycle time Minimum temperature distribution on cavity and/or core Minimum temperature distribution between cavity and core Whether high thermal conductivity inserts should be used

Analysis Type

Objectives determines are cooling analyses are run There are two analysis types

Manual analysis A cycle time is input into the analysis Best if there is a known cycle time Best if the cooling layout is poor

Automatic analysis Calculates the cycle time for you Best for minimizing cycle time Automatic analysis should not be run if the cooling layout is poor, because cycle times will be extended.

Automatic Analysis

Cycle time is calculated by

Making sure the part is 100% frozen 100% frozen is the default, but the value can be defined

Average of mold surface temperatures (top and bottom) for all elements is within 1C of the target mold temperature

Analysis Advanced Parameters

Mold temperature convergence tolerance Maximum number of mold temperature iterations Geometric influence

Geometry Influence Parameter (GIP)

Geometric influence option

Automatic The software calculates the minimum number of surrounding elements required to produce accurate cooling results for each element, which is faster and requires less computing time.Automatic

Ideal The calculation for each element takes into account all other elements in the modelIdeal

Geometry Influence Parameter (GIP)

How it is used

Geometry Influence Parameter (GIP) Tips

Use default automatic setting unless an issue arises

Good to use when optimizing water lines

Ideal should be used if going on to warpage Parameter can be used but not typically recommended for warpage

Automatic ~ GIP 10, so for large models you can set the parameter lower Reduces memory requirements but may affect accuracy of results

Set to a high number (20-30) if Ideal gives problems

Cooling Memory Errors

ERROR 702270 Disk Space Free up more disk space for both job manger temp and project directories Change GIP, especially if running Ideal If using a large model, change GIP to 6-10 Upgrade to higher amount of disk space ERROR 700080 Memory (RAM + SWAP) Increase swap size Swapping to hard drive increases analysis time significantly Watch CPU usage when swapping, normally under 10%

Upgrade to higher amount of RAM Try to lower element count Remesh Convert Fusion > Midplane model

Fusion Thickness Change Issue

MPI allow you to manually change element thickness properties

Does not move mesh OK for Flow

Issue for cooling as solver (Boundary Element Method) relies partially on mesh location Heat flux calculations do use thickness property

Typically gives accurate results

This issue affects warp results Most accurate results obtained by making changes in CAD and re-importing Fusion mesh

When to Run Cooling

Model part & mold Fill

Warp

Optimize filling of the part Balance/size feed system Possible packing

Cooling

Determine type (midplane only) Determine magnitude Determine cause Reduce warpage

Minimize temp differences DONT run filling as input to coolOptimize packing if necessary, Use cooling as input to Flow, cooling may have strong influence on packing

Flow

Exercise

Run a cooling analysis on the dustpan

Set inlets locations with Reynolds number Water temperature 10,000 25 C 40 C 225 C 5 sec Specified 15 sec Ideal

Run analysis with the following inputs Mold surface temp: Melt temp: Mold-open: Inj + Pack + Cooling: Geometry influence:

Run a second cooling analysis with Automatic IPC Compare the results from the two analyses

Results SummaryTarget Mold Temperature 40 C

Automatic AnalysisSummary of Cavity Temperature Results ===================================== Cavity temperature - maximum Cavity temperature - minimum Cavity temperature - average Average mold exterior temperature Cycle time = = = = = 54.6 29.4 39.8 26.9 66.0 C C C C s

Specified AnalysisSummary of Cavity Temperature Results ===================================== Cavity temperature - maximum Cavity temperature - minimum Cavity temperature - average Average mold exterior temperature Cycle time= = = = = 91.2 35.6 59.0 29.2 20.0 C C C C s

Top Temperatures

Max Temp 54.6 C

Specified analysis Cycle time 20 sec. Avg. cavity temp. 59.0C

Automatic analysis Cycle time 66.0 sec. Avg. cavity temp. 39.8C Target mold temp. 40C

Maximum Temperature

Max Temp 54.6 C

Manual analysis Cycle time 20 sec. Avg. cavity temp. 59.0CEjection temperature 107C

Automatic analysis Cycle time 66.0 sec. Avg. cavity temp. 39.8C Target mold temp. 40C

Average Temperature

Max. Value 46.0 Manual analysis Cycle time 20 sec. Automatic analysis Cycle time 66.0 sec. Target mold temp. 40C

Time to Freeze

Max. Value 15.7 secManual analysis Cycle time 20 sec. Automatic analysis Cycle time 65.6 sec.

Coolant Temperature

Max. Value 26.0Manual analysis Cycle time 20 sec. Automatic analysis Cycle time 65.6 sec.

QUESTIONS?