AMEM 405 slide 1 Manufacturing Processes with the Aid of CAD/CAM Systems AMEM 405 Dr. Sotiris Omirou AMEM 405 slide 2 CONTENTS 1. CAD/CAM definition 2. Review of Milling Process 3. Know The CNC Machine 4. Zero Reference Point 5. Absolute Vs Incremental Coordinates 6. CNC Programming 1
AMEM 405 slide 3 1. CAD/CAM - Definition CAD - Computer Aided Design CAM - Computer Aided Manufacturing. The combined CAD/CAM is the technology concerned with the use of computers to perform product designing and manufacturing operations. AMEM 405 slide 4 Structure of a CAD/CAM system CAD Program DXF File CAM Program CNC File CNC Machine Computer Aided Design Geometry of part is created Computer Aided Manufacturing Program the part with G/Mcodes Computer Numerical Control Produce the part Milling Lathe etc. 2
AMEM 405 slide 5 The functions of CAM programs CAM program NC codes CAM programs define: method of machining feature/shape to machine tool used for machining path of the tool AMEM 405 slide 6 2. Review of Milling Process 3
AMEM 405 slide 7 Vertical Milling Machine AMEM 405 slide 8 Conventional vertical milling machine 8 4
AMEM 405 slide 9 CNC milling machine AMEM 405 slide 10 Automatic Tool Changer 5
AMEM 405 slide 11 Automatic Tool Change on a CNC Milling Machining center AMEM 405 slide 12 6
AMEM 405 slide 13 MILLING AMEM 405 Milling Tools slide 14 7
AMEM 405 slide 15 Milling Tools and Tool Inserts AMEM 405 slide 16 Drills and Reamers 8
AMEM 405 slide 17 Milling Operations Facing: removes material across the top surface Contouring: removes material to a specified depth along a CAD geometry Drilling: uses points identified on a CAD layer to drill holes to a specified depth Pocketing: removes all material within the outline of a CAD geometry Surface of Revolution: removes all material within a surface generated by revolving geometry about the X or Y axis AMEM 405 slide 18 9
AMEM 405 slide 19 AMEM 405 slide 20 3-Dimensinal surface milling: 10
AMEM 405 slide 21 AMEM 405 slide 22 11
AMEM 405 slide 23 3. Know The CNC Machine AMEM 405 slide 24 The CNC operator must understand: - the machine's basic components - its directions of motion - all buttons and switches on the machine tool itself. 12
AMEM 405 slide 25 The machine's basic components AMEM 405 slide 26 Directions Of Motion 13
AMEM 405 slide 27 Axis Directions AMEM 405 slide 28 Axis Directions X Axis 14
AMEM 405 slide 29 Y Axis AMEM 405 slide 30 Z Axis 15
AMEM 405 slide 31 Linear axis of motion AMEM 405 slide 32 Rotational axis of motion 16
AMEM 405 slide 33 Buttons and switches AMEM 405 slide 34 Control panel of HEIDENHAIN 17
AMEM 405 slide 35 4. ZERO REFERENCE POINT or PROGRAM ZERO AMEM 405 slide 36 Program Zero Allows ALL Program Coordinates To Be Taken From A Common Location. 18
AMEM 405 slide 37 Program Zero Can Be Compared To The Origin Of A Rectangular Coordinate System Zero point for milling machine Z Y AMEM 405 slide 38 X 19
Z AMEM 405 slide 39 Y X With CNC, Points Are Plotted In Space Z AMEM 405 slide 40 Y X LINEAR MOTION IN X, Y, Z AXES 20
Z AMEM 405 slide 41 Y X LINEAR MOTION IN Z AXIS Z AMEM 405 slide 42 Y X LINEAR MOTION IN X AXIS 21
Z AMEM 405 slide 43 Y X LINEAR MOTION IN Z- AXIS Z AMEM 405 slide 44 Y X LINEAR MOTION IN Z+ AXIS 22
AMEM 405 slide 45 XY Plane Y+ Program Zero X- X+ Y- AMEM 405 slide 46 Program Zero Can Be Located Anywhere Where Do we Place The Program Zero Point? This Decision Is ALWAYS Based On How The Part Is Dimensioned. 23
In AMEM X 405 & Y: slide 47 20 17 0 7 5 0 5 10 25 30 Program Zero AMEM 405 slide 48 HOLE POSITION X=5, Y=5 20 17 0 7 5 0 5 10 25 30 Program Zero 24
HOLE POSITION X=5, Y=20 AMEM 405 slide 49 20 17 0 7 5 0 5 10 25 30 Program Zero HOLE POSITION X=30, Y=20 AMEM 405 slide 50 20 17 0 7 5 0 5 10 25 30 Program Zero 25
HOLE POSITION X=30, Y=5 AMEM 405 slide 51 20 17 0 7 5 0 5 10 25 30 Program Zero In AMEM X 405 & Y: slide 52 100 diam. Drill 4 holes eq. spaced 26
In AMEM X 405 & Y: slide 53 100 diam. Drill 4 holes eq. spaced HOLE POSITION X=50, Y=0 In AMEM X 405 & Y: slide 54 100 diam. Drill 4 holes eq. spaced HOLE POSITION X=0, Y=50 27
In AMEM X 405 & Y: slide 55 100 diam. Drill 4 holes eq. spaced HOLE POSITION X=-50, Y=0 In AMEM X 405 & Y: slide 56 100 diam. Drill 4 holes eq. spaced HOLE POSITION X=0, Y=-50 28
In Z: AMEM 405 slide 57 Y+ X- X+ Y- Top View Z+ X- X+ Z- Front View In Z: AMEM 405 slide 58 Y+ X- X+ Y- Z Zero Top View Z+ X- X+ Z- Front View 29
AMEM 405 slide 59 The Machine Has To Know Where Program Zero Is Assigned AMEM 405 slide 60 Setting Workpiece Zero Point 30
AMEM 405 slide 61 5. Absolute Vs Incremental Coordinates AMEM 405 slide 62 ABSOLUTE MODE When Working From Program Zero, You Are Programming In The ABSOLUTE MODE. G90 Specifies The Absolute Mode. 31
AMEM 405 slide 63 INCREMENTAL MODE In The Incremental Mode, Movements Are Given From The Tool's LAST POSITION. G91 Specifies The Incremental Mode AMEM 405 slide 64 I A B S O L U T E N C R E M E N T A L 32
AMEM 405 slide 65 Advantages of the ABSOLUTE MODE: Coordinates Are Easier To Calculate Programmed Coordinates Make Sense Mistakes Are Not Compounded AMEM 405 slide 66 6. CNC Programming 33
AMEM 405 slide 67 The Part Program AMEM 405 slide 68 34
AMEM 405 slide 69 AMEM 405 slide 70 Writing A CNC Program Is Like Giving A Set Of Step By Step Instructions 35
AMEM 405 CNC or Part Program slide 71 Example command for linear motion: N10 G90 G01 X70 Y85 F300 S2000 where, N10 G90 G01 X and Y F S - A sequence number; - Abslolute Mode - Linear motion - Coordinate positions (mm) - Feed rate (300 mm/min) - spindle speed (2000 rev/min) CNC or Part Program AMEM 405 slide 72 Complete part program consists of a sequence of commands 72 36
AMEM 405 slide 73 Basic Codes for CNC Programming CODE MEANING G M N Gxx G code Mxx M code Command sequence number F Feedrate (mm/min) S Spindle speed (RPM) T Tool number X, Y, Z Coordinates (mm) R Radius (mm) AMEM 405 slide 74 Commonly used G and M codes G CODE MEANING M CODE MEANING G90 Absolute Mode M03 Spindle ON - CW G91 Incremental Mode M06 T Tool Change G70 Units in inches M08 Coolant ON G71 Units in mm M09 Coolant OFF G00 Linear Motion - Rapid M30 Program End G01 G02 G03 Linear Motion - Feedrate Circular Motion CW Circular Motion CCW 37
AMEM 405 slide 75 Modal Words Words That Are Modal Do NOT Have To Be Repeated In Subsequent Commands AMEM 405 slide 76 Modal Words Example: N010 G00 X30 Y40 N015 X60 Y80 38
AMEM 405 slide 77 There Are 20-30 CNC Words Used Regularly In CNC Programs Think Of This As Learning A Foreign Language That Contains Only 30 Words. AMEM 405 slide 78 Points About G Words Most Are Modal Some Are "One Shot" Three Compatible G Codes Can Be Used Per Command Some G Codes Might Be Initialized 39
AMEM 405 slide 79 Points About M Words M Codes Are Like Programmable On/Off Switches Only One Per Command AMEM 405 slide 80 Other Notes About Programming Words Order Within A Command Is Unimportant Be Sure To Use The Decimal Point When Allowed 40