cnc machine ppt

8/12/2019 CNC Machine PPT

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DEVELOPMENTS IN

CNC MACHINES


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INTRODUCTION

CNC machines are the most standardized form ofmanufacturing the parts required to produce a productand The earliest CNC machines received codeinstructions through hard-wired controllers, whichmeant that the programming format could not be alteredin 1970 s and in this presentation we can seedevelopments in the tools, tool holding devices, work

holding devices, machining technique, and referencemeasurement etc


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ELEMENTS OF A NC SYSTEM

1. PROGRAMMING

2. TOOLING3. MACHINING

4. TOOL HOLDING

5. WORK HOLDING

6. REFERENCE MEASURING

7. IN PROCESS INSPECTION


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1. PROGRAMMING SYSTEMS

O0013

N0005 G53

N0010 T0404

N0020 G57 G00 X26.00 Z0.0 S500 M04N0030 G01 X-0.20 F100

G01 Linear interpolation (cutting)

X-0.20 Move only in x direction until you pass

the center by 0.1 mm (facing)F100 Set feed rate to 100 mm/min.

G00 Move rapidly away from work piece (no

cutting) to location x= 23.0 (11.50 from zero)

and z = 2.0.

APT Program Interpretation


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Automatic Part Programming: Developments

Software can generate program automatically from model

Make 3D model

Define Tool

CNC data

Simulate

cutting

Part program

Generation andMachining


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Automatic part programming and CNC

Very complex part shapesvery large NC program

NC controller memory may not handle HUGE part program

computer feeds few blocks ofNC program to controller

When almost all blocks executed,controller requests more blocks


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2. DEVELOPMENTS IN TOOLING

HSS TOOLS

POLY CRYSTALLINEDIAMOND TOOLSCEMENTED CARBIDE


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3. Conventional machining

Rough machining and semi finishing with thematerial in a soft i state (30-40hrc)

Heat treatment to obtain the required hardness (55-60hrc)

Electron discharge machining of particular zones ofthe die or of the matrix with very small rays or very

deep cavities Finishing of the remaining part of the die

Manual working to obtain the geometry and accuracyrequired manual polishing


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HIGH SPEED MACHINING

High speed rough machining and semi finishing withthe material in a solid state (30-40hrc)

Heat treatment to obtain required hardness (55-60hrc)

High speed finishing and super finishing with the toolsuitable for the specified material


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DEVELOPMENTS IN PROGRAMMING

Cutter dia: 63mm(3/4th used)

Depth of cut: 6mm

Spindle speed: 800 rpm Feed rate: 0.6 meters/min

Metal removal rate:170cm

3/min

Cutter dia: 63mm

(3/4th

used)

Depth of cut: 2mmSpindle speed: 2800 rpm

Feed rate: 3.8 meters/min

Metal removal rate:

243cm 3/min

High speed machiningConventional machining


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HSK : Hohl Shaft Kegel

(German)Means

Hollow Shank Taper

Using centrifugal force

principal and through

coolant holders

USED FOR SPEEDS 10000


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5. WORK HOLDING DEVICES


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DEVELOPMENTS IN WORK HOLDING

DEVICESHydraulic clampingPneumatic clamping

Vacuum clamping Magnetic clamping


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6. REFERENCE MEASURING

Dial gauge : Used for dialing the fixtures andtaking references of the work pieces

Touch probe : Used for takingReferences of the work pieces

Which directly enters the

reference values in the work

Coordinates of the machine


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7. INPROCESS INSPECTION

The touch probe can inspect the preprogrammed

dimensions in the machine itself and the dimensionalReport can be saved and even taken a Print out.


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NC MACHINE OF 1970s LATEST 5-AXIS CNC MACHINE

5-AXIS MACHINE AT DIFFERENT ORIENTATIONS

cnc machine ppt

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