HistoryHistory

• 1952 – 1st generation NC The first NC-1952 1st generation NC, The first NC-controlled machine for metal processing (relays and electronic tubes)

• 1960 – 2nd generation NC, relays and electronic tubes was replaced with tranistors

• 1965 – 3rd generation, integrated circuits

• 4th generation NC – CNC (computerized t ge e at o C C C (co pute ednumerical Control

CNC Machines examplesCNC�Machines�� examples

• Machine tools for�cutting (lathe,�millingmachine,�machining centre)g )

• CMM�– Coordinate Measuring Machine

Sh l i hi ( b k• Sheet metal�processing machines (press�brake,�punch press,�laser�/�waterjet cutting machine)

• RP�(rapid�prototyping)�and�rapid�manufacturing machinemanufacturing machine

Basic ComponentBasic Component

P t P Machine Control Part Program Machine Control Unit

Processing equipmentStep by step commands

that direct the actions of Microcomp ter andthe processing equipment Microcomputer and

related control hardware that stores the program of instructions and executes

it by converting each command into

mechanical actions of the processing equipmentprocessing equipment

Configurations examples (1)Configurations – examples (1)

Configurations examples (2)Configurations – examples (2)CNC Machines examplesCNC�Machines�� examples

• Machine tools for�cutting (lathe,�millingmachine,�machining centre)g )

• CMM�– Coordinate Measuring Machine

Sh l i hi ( b k• Sheet metal�processing machines (press�brake,�punch press,�laser�/�waterjet cutting machine)

• RP�(rapid�prototyping)�and�rapid�manufacturing machinemanufacturing machine

TerminologyTerminology

3 i• 3�axis– Movement along 3�axes is�CNC�controlled (also called

2½D hi i )2½D�machining)

• 4�axis�– 6�axis– 3�axes�+�1�to�3�rotation(s)

• 7�axis– Combines milling and�turning�in�one machine

• Active tools– Motor�driven�tools in�a�machine that�normally does

not�have this

Positioning and fixturingPositioning and�fixturing

• 3�2�1�Method

Secondary supportsSecondary supports

• For�flexible�(thin walled)�components

Machine vice (skruvstäd)Machine vice�(skruvstäd)

• Easy�to�operate

• Does not position component very accuratelyDoes�not�position�component very accurately

• Deformation�can be�a�problem

Actuators - Motors 2(2)Actuators Motors 2(2)

• Electric motors (Most Common)Electric motors (Most Common)– DC Motors

AC Motors– AC Motors– Step Motors

Linear Motors– Linear Motors• Hydraulic motors (Not commonly used)

Linear DrivesLinear Drives

• To transfer the rotational movement to aTo transfer the rotational movement to a linear movement – Ball screw

Ball screw : http://www.ostergrens.se B ll htt // iBall screw : http://www.ostergrens.se Ball screw: http://www.eie.se

Ball screw 2(2)Ball screw 2(2)

• Why Ball-screw?Why Ball screw?– High efficiency (>90%)

Low heat generation– Low heat generation– No backlash

Hög precision– Hög precision– High resistance to wear

Inserts - CarbideInserts Carbide

Cutting Tools

Summ

ary of cutting technology:

Workpiece m

aterial, parameters, tool

geometry infuence:

� which shapes can be m

achined o or w

hich tool needs to be used � cutting forces

o required power

o deflections � costs (cutting tim

e vs tool wear)

� chip control � surface roughness � vibrations

This means that the C

NC

programm

er m

ust be a skilled machinist also …

.. two

completely different skills!

Exam

ple: Some N

C program

keys SINU

ME

RIK

805

G00

Traversing G

01 Linear interpolation

G02

Circular interpolation clockw

ise G

03 C

ircular interpolation counter clockwise

G10

Polar coordinates, Traversing G

11 Polar coordinates, Linear interpolation

G12

Polar coordinates, Circular interpolation

clockwise

G13

Polar coordinates, Circular interpolation

counter clockwise

G17

Programm

ing in X-Y

plane G

40 End of radius com

pensation G

41 R

adius compensation left (tool stays left

of programm

ed contour) G

42 R

adius compensation right (tool stays

right of programm

ed contour) G

54 U

ser defined origin G

90 A

bsolute programm

ing G

91 Increm

ental programm

ing

X

X

-coordinate Y

Y-coordinate

Z

Z-coordinate A

Angle

U

R

adius I

Interpolation origin X

-coordinate J

Interpolation origin Y

-coordinate K

Interpolation origin Z-coordinate D

1-99 Tool com

pensation D

0 End of tool com

pensation

F

Feedrate S

Spindle speed

T

Tool number

H

H

elp function L

sub-program

M

02 Program

end M

17 Sub-program

end M

30 Program

end M

03 Spindle rotation clockw

ise M

04 Spindle rotation counter clockw

ise M

05 Spindle stop

Specific for Cortini: Tool change has form

at: Tx L6 D

yw

here: "x" is the tool slot position of the new tool

and "y" is the register for tool size compensation

belonging to that tool (L6 is a sub-program for tool

changes)

Some lathes sw

ap G02 and G

03

Vertical latheVertical lathe• Requires less�floor space

• Upside�down mounting possible– Easier chip�removalp

CMM�– Coordinate MeasuringgMachine

• For�instance,�for�inspection

Examples of probesExamples of�probes

Laser probesLaser�probes

• Higher density (more points)

• Suitable for ”reverse engineering”Suitable for� reverse engineering

Sheet metal processing machinesSheet metal�processing machines

Examples:

• CNC press brakeCNC�press�brake

• Punch press

• Laser�cutting machine

• Laser pressLaser�press

• Waterjet cutting machine

• Laser�welding machine

Air bending set�up

CNC Press brake (usually hydraulic)CNC�Press�brake (usually hydraulic)

• CNC�control of�punch (or�die),�finger�stops,�crowning device (bombering)g ( g)

Detailed view (1)Detailed view (1)

Detailed view (2)Detailed view (2)Robot assisted punch pressRobot�assisted punch press

LASER�(Light�Amplification�by�Stimulated�Emission�of�Radiation)

Most used: CO Nd:YAG ExcimerMost used:�CO�,�Nd:YAG,�Excimer

Laser cuttingLaser�cutting• With�or�without gas�(inert/reactive)

• Related:�welding,�hardening,�engraving,�…

Beam guided by mirrors or fiberBeam guided by�mirrors or�fiber

• Nd:YAG,�Excimer laser�beams can be�guidedthrough an�optical fiber�– but less�powerfulg p pthan CO2

Laser cutting machine (example)Laser�cutting machine (example)

6 axis Laser (3D)6�axis�Laser�(3D)

Construction principlesConstruction�principles

Considerations/problemsConsiderations/problems

• Risk�for�overshoot when moving high�massand/or�at�high�speedg p– Speed�reduction (corner�anticipation).�Has�process�

limitations (power density)limitations�(power�density)

– Smart�path planning

d l f ?• How to�avoid tangling of�components?– Drop down table

– Leaving small�”bridges”�until last

Waterjet cuttingWaterjet cutting

• Similar,�but 3�axis�and�2�axis�more common

RP (rapid prototyping)RP�(rapid�prototyping)

i l l (d k hi i )• Material�removal�(desktop�machining)• Layered manufacturingy g

– Adding material– Transforming material (solidification)Transforming material�(solidification)

• Some process�so�good that�one talks�about”rapid manufacturing”rapid�manufacturing– Often,�one of�a�kind�products

• Based on�CAD�drawing or�scanned surfacedata

Example of layered manufacturingExample of�layered manufacturing

Complex Parts – How to program?Complex Parts How to program?

CAM – Computer Aided M f iManufacturing

External CAD systemIntegrated CAD/CAM system

CADProduct design

CAMGeometry Definition

yProduct Design

Neutral formatDefine Operation

Select Tools

Define ToolPaths

Neutral format

e.g. Step, iges

Simulate Toolpath

Postprocess

Simulate Machine

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1

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3

Computer Aided ManufacturingComputer Aided Manufacturing