CC7211 -CAM LAB

LAB MANUAL

CC7211 CAM LAB L T P C

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Simulation and Machining using CNC / DNC Machine Tools – Use of FEM

Packages - Relational

Data Base – Networking – Practice on Computer Aided Measuring

Instruments - Image

Processing – Software Development for Manufacturing – CNC Controllers

– Use of advanced

CNC Machining Packages – Business Data Processing.

EQUIPMENTS FOR CAM LAB

1. CAM Software for tool path generation for planermachining, contour

machining, drilling, turning etc. &post processing modulus for different CNC

controllers : 10 Nos

2. Medium production type CNC turning center with

popular industrial type controller : 1

3. Medium production type CNC machining center

with popular industrial type controller : 1

4. Bench Model CMM : 1

5. Vision & image processing software : 2

6. Data Processing Software : 2

TOTAL: 30 PERIODS

LIST OF EXPERIMENTSSl.no topics Page

no.

1 INTRODUCTION TO CAM

2 CHAMFERING OPERATION

3 GROOVING OPERATION

4 PLAIN TURNING

5 TAPER TURNING

6 THREAD CUTTING

7 CIRCULAR INTERPOLATION

8 DRILLING OPERATION

9 PECK DRILLING OPERATION

10 INTRODUCTION of CMM (Coordinate Measuring

Machine)

.

EX.NO.1

Introduction to Computer Aided Manufacturing

INTRODUCTION

Many achievement in computer aided design and manufacturing have a common origin in number control. The frame work established during the developed of numeric control is till undergoing future reforming and enhancement in today.

NUMERIC CONTROL

It is defined as a form of programmable automation in which the process is controlled by number letters and symbols. In NC the number form a program instructions defined for a particular path.

NC technology has been applied to unite several of operations including assembly inspection, sheet metal process working and spot welding.

COMPONENTS OF NC SYSTEM

Program of instruction

Control unit

Machine tool

PROGRAM OF INSTRUCTION

The program of instruction is the shop by sleep of directions which tell the machine tool. What to do it is leaded in the numerical or symbolic from one types of input medium that can be interpreted by controlled unit the most common input medium is punched type.

CONTROL UNIT

It Includes:

1. Data Processing Unit (DPU) with memory.

2. Control loops unit which are connected to the servo motors to control the machine tool operation.

3. Feed back device to make sure that the instructions have been properly executed by the machine

CNC CONTROLLERS

Many different types of controllers are available in the market However; they fall into two major categories;

Point-To-Point and Continuous Path.

Point-to-point control systems cause the tool to move to a point on the part and execute an operation at that point only. The tool is not in continuous contact with the part while it is moving.

Continuous-path controllers cause the tool to maintain continuous contact with the part as the tool cuts a contour shape. These operations include milling along any lines at any angle, milling arcs and lathe turning.

FLOW OFCOMPUTER-AIDED CNC PROCESSING/ NC PROCEDURE

• Develop or obtain the 3D geometric model of the part, using CAD.

•Decide which machining operations and cutter-path directions are required (computer assisted).

•Choose the tooling required (computer assisted).

•Run CAM software to generate the CNC part program.

•Verify and edit program.

•Download the part program to the appropriate machine.

•Verify the program on the actual machine and edit if necessary.

•Run the program and produce the part.

COMMONLY USED WORD ADDRESSES

Addresses Meaning

F Feed rate command

G Preparatory function

M Miscellaneous command

N Sequence number

R Arc radius

S Spindle speed

T Tool number

X x-axis data

Y y-axis data

Z z-axis data

KEY BOARD FUNCTIONS:

F1 help

F2 save

F3 load

F4 simulation

F5 main menu

PREPARATORY FUNCTION (‘G’ CODES)

G00 Rapid traverse

G01 Linear interpolation

G02 Circular interpolation, CW

G03 Circular interpolation, CCW

G04 Dwell

G08 Acceleration

G09 Deceleration

G17 X-Y Plane

G18 Z-X Plane

G19 Y-Z Plane

G20 Inch Units (G70)

G21 Metric Units (G71)

G40 Cutter compensation – cancel

G41 Cutter compensation – left

G42 Cutter compensation- right

G70 Inch format

G71 Metric format

G74 Full-circle programming off

G75 Full-circle programming on

G80 Fixed-cycle cancels

G81-G89 Fixed cycles

G90 Absolute dimensions

G91 Incremental dimensions

OFTEN USED MISCELLANEOUS "M" CODES

M00 The M00 code is used for a Program Stop command on the machine.

It stops the spindle, turns off coolant and stops look-a-head processing.

Pressing CYCLE START again will continue the program on the next block of the program.

M01 The M01 code is used for an Optional Program Stop command.

Pressing the OPT STOP key on the control panel signals the machine

to perform a stop command when the control reads an M01 command.

It will then perform like an M00.

M03 Starts the spindle CLOCKWISE. Must have a spindle speed defined.

M04 Starts the spindle COUNTERCLOCKWISE. Must have a spindle speed defined.

M05 STOPS the spindle.

M06 Tool change command along with a tool number will execute a

tool change for that tool. This command will automatically stop the spindle, Z-axis will move up to the machine zero position and theselected tool will be put in spindle. The coolant pump will turn off right before executing the tool change.

M08 Coolant ON command.

M09 Coolant OFF command.

M30 Program End and Reset to the beginning of program.

M97 Local Subroutine call

M98 Subprogram call

M99 Subprogram return (M98) or Subroutine return (M97), or a Program loop.

EXNO.2 CHAMFERING OPERATION

CHAMFERING OPERATION

EXNO3

EXNO4

EXNO 5

TAPER TURNING

EX.NO 6

THREAD CUTTING

EX.NO 7

EX.NO 8

EX.NO 9

EX.NO.10.

INTRODUCTION of CMM (Coordinate Measuring Machine)

Understanding The CMM: The Coordinate System

We use a coordinate system to describe the movements of a measuring machine.  The coordinate system, invented by the famous French philosopher and mathematician René Descartes in the early 1600's, lets us locate features relative to other features on workpieces.

A coordinate system is a lot like an elevation map where the combination of a letter along one edge of the map, a number along the other, and elevations shown throughout uniquely describes each location on the map.  This letter/number/elevation combination is called a coordinate and represents a specific place relative to all others.

Another example is a street map with buildings shown (Figure 1).  To walk to your hotel room at the Ritz Hotel from the train station (your origin), you walk 2 blocks along Elm street, 4 blocks on Maple and up 3 floors in the Ritz.  This location can also be described by the coordinates 4-E-3 on the map, corresponding to the X, Y and Z axes on the machine.  These coordinates uniquely describe your room and no other location on the map.

Understanding The CMM A coordinate measuring machine (CMM) works in much the same way as your finger when it traces map coordinates; its 3 axes form the machine's coordinate system.  Instead of a finger, the CMM uses a probe to measure points on a workpiece (Figure 2).  Each point on the workpiece is unique to the machine's coordinate system.  The CMM combines the measured points to form a feature that can now be related to all other features.

The Coordinate System: The Machine Coordinate System

There are two types of coordinate systems in the world of measurement.  The first is called the Machine Coordinate System.  Here, the X, Y, and Z axes (Figure 3) refer to the machine’s motions.  When viewed from the front of the machine, the X axis runs from left to right, the Y axis runs from front to back, and the Z axis runs up and down, vertically perpendicular to the other two.

The Coordinate System: The Part Coordinate System

The second coordinate system is called the Part Coordinate System where the 3 axes relate to the datums or features of the workpiece.

Before the introduction of computer software to coordinate measurement, parts were physically aligned parallel to the machine’s axes so that the Machine and Part Coordinate Systems were parallel to one another.  This was very time consuming and not very accurate.  When the part was round or contoured, rather than square or rectangular, the measurement task was nearly impossible.

Measured and Constructed Features

What’s the Difference Between Measured and Constructed Features? The vast majority of workpieces are made up of simple geometric elements created by machining or forming.  These primary elements (planes, edges, cylinders, spheres, cones, etc.) are called features.  When a CMM can measure these features directly, by touching the surfaces that make up the feature with a probe, the features are referred to as measured features.

Other features, such as distance, symmetry, intersection, angle and projection, cannot be measured directly but must be constructed mathematically from measured features before their values can be determined.  These are called constructed features.  In Figure 11 the centerline circle is constructed from the center points of the 4 measured circles.

Constructed Features

The relationships between one feature or group of features to another feature or group of features are critical to manufacturing.  For example, the intersect point between the cylinders on one side of an engine block and those on the other side determines how well mating parts fit (Figure 12).  This intersect point is constructed from the two measured features (the engine cylinders).

Lab Objective:

1. Familiar with CMM2. Qualify the probe3. Align block 4. Measurement dimensions.

Lab instruction:

Refer to block_measurement.pdf

Lab output:

Each person in the group does one measurement on each geometry on the block and fills out the form. Then Calculate their distribution and standard deviation of measurements.

Optional:

You can bring your own part and measure their dimensions.