logo dr. habeeb hattab habeeb dr. habeeb hattab habeeb office: bn-block, level-3, room-088 email:...

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Dr. HABEEB HATTAB HABEEBDr. HABEEB HATTAB HABEEB

Office: BN-Block, Level-3, Office: BN-Block, Level-3, Room-088Room-088Email: Email: [email protected]@yahoo.comExt. No.: 7292Ext. No.: 7292

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Lecturer: Dr. HABEEB ALANI University TENAGA NasionalLecturer: Dr. HABEEB ALANI University TENAGA Nasional

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UUniversity TENAGA Nationalniversity TENAGA National

College Of EngineeringCollege Of EngineeringMechanical DepartmentMechanical Department

Academic Year – 2008-2009Academic Year – 2008-2009

Lecture NoteLecture NoteLecture NoteLecture Note

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LOGOComputer Aided ManufacturingComputer Aided Manufacturing UNITENUNITEN


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Computer Aided Manufacturing

The purposes of design modeling The purposes of design modeling / // / is to capture the is to capture the

design concept in a sharable medium. design concept in a sharable medium.

Traditionally this medium has been a piece of paper. Traditionally this medium has been a piece of paper.

Since engineering objects are mostly three dimensional, Since engineering objects are mostly three dimensional,

the model in the form of a drawing must be capture all the model in the form of a drawing must be capture all

the details of the design on this two-dimensional the details of the design on this two-dimensional

medium. medium.

Design Modeling RequirementsDesign Modeling Requirements


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Engineering drafting standardizes the following:Engineering drafting standardizes the following:

• Symbols Symbols

• FormatsFormats

• Conventions used in drawing engineering objects. Conventions used in drawing engineering objects.

Drafting geometry:Drafting geometry:

LineLineCircleCircleCurveCurve---etc.-------etc.----

Drafting functions:Drafting functions:

AddAddDeleteDeleteModifyModify---etc.-------etc.----

Design Modeling Requirements


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The importance results for using of CAD system:The importance results for using of CAD system:

• More flexible than a manual drafting system.More flexible than a manual drafting system.

• Can produce more precise conventional engineering drawing. Can produce more precise conventional engineering drawing.

• CAD replace paper-and-pencil based drafting with higher CAD replace paper-and-pencil based drafting with higher

efficiency.efficiency.

• CAD opens other possibilities in design modeling.CAD opens other possibilities in design modeling.



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Modeling objects features:Modeling objects features:

• Enhance to generation of multiple views.Enhance to generation of multiple views.

• All geometric entities are modeled in the 3D space (X, Y, All geometric entities are modeled in the 3D space (X, Y,

and Z).and Z).

• 3D CAD model can be rotated and viewed from any 3D CAD model can be rotated and viewed from any

angle.angle.

• NC part programming requires can be taken directly from NC part programming requires can be taken directly from

the model.the model.

• 3D CAD model contain richer information than a 2D 3D CAD model contain richer information than a 2D

drafting model. drafting model.



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Disadvantages of 3D CAD model:Disadvantages of 3D CAD model:

• Dimensions and tolerances are so difficult to present Dimensions and tolerances are so difficult to present

with 3D model.with 3D model.

• 3D wire frame model lacks face information and does not 3D wire frame model lacks face information and does not

have the volume property.have the volume property.

• 3D wire frame not complete and unambiguous model.3D wire frame not complete and unambiguous model.

• No correct section views can be generated. No correct section views can be generated.


3D solid model:3D solid model:

• 3D solid model3D solid model revealed all details for the objects inside, revealed all details for the objects inside,

outside, edges and others.outside, edges and others.


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Design model information:Design model information:

• GeometryGeometry

• TolerancesTolerances

• Volume (for some applications and available only in solid Volume (for some applications and available only in solid

models)models)

• AnnotationAnnotation



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Computer Aided ManufacturingClassification of geometric modeling techniquesClassification of geometric modeling techniques

Geometric ModelsGeometric Models

3-D2-D

Wire frameWire frame

Finite Element MeshFinite Element Mesh

Wire frame

Wire frame

Finite Element Mesh

Finite Element Mesh

SurfaceSurface

SolidSolid

Hybrid


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The Age of Computers

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Computer Aided ManufacturingWhat is the Computers-Aided Design?What is the Computers-Aided Design?

The use of computer to assist for creation and The use of computer to assist for creation and

manipulation- design model represented as a digital data manipulation- design model represented as a digital data

or computer image to assist engineering the design or computer image to assist engineering the design

processprocess

CC AA DD


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A CAD system usually consists of:A CAD system usually consists of:

1.1. hardware: the computer and associated peripheral equipment.hardware: the computer and associated peripheral equipment.

2. Software: the computer program(s) running on the hardware.2. Software: the computer program(s) running on the hardware.

3. Data or model created and manipulated by the software.3. Data or model created and manipulated by the software.

4.Human knowledge and activities.4.Human knowledge and activities.

Computers-Aided Design?


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HardwareHardware ::

Input DevicesInput Devices

– – Keyboard, MouseKeyboard, Mouse

– – Light pens, Data Tablets Light pens, Data Tablets

Computers-Aided Design?


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Output DevicesOutput Devices

- CRT Monitors, Flat Panel Displays- CRT Monitors, Flat Panel Displays

– – Plotters, Printers Plotters, Printers

Hardware


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The First 2D Software – SKETCHPAD…The First 2D Software – SKETCHPAD…

• • Developed at MIT by Developed at MIT by Ivan Sutherland in 1963Ivan Sutherland in 1963..

• • Allowed the user to interact with a computer graphically.Allowed the user to interact with a computer graphically.

– – CRT monitor, Light Pen, Graphical InterfaceCRT monitor, Light Pen, Graphical Interface

CAD systemsCAD systems


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The historical evolution of CAD systemThe historical evolution of CAD system

--Business system required large computer connecting --Business system required large computer connecting to many terminalsto many terminals

1st CAD project, MIT in 1959 - 1960, by Ivan Sutherland, 1st CAD project, MIT in 1959 - 1960, by Ivan Sutherland,

developed SKETCHED system, which was an early drawing developed SKETCHED system, which was an early drawing

processing system that used computers, the system includedprocessing system that used computers, the system included

most of the concepts of today's interactive 2D CAD system.most of the concepts of today's interactive 2D CAD system.

General Motors DAC-1General Motors DAC-1

Lockheed Corp. CADAM for business application in 1967Lockheed Corp. CADAM for business application in 1967



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--Mini-computer to dedicated graphics terminal--Mini-computer to dedicated graphics terminal

Applicon Corp. introduced AGS in 1968Applicon Corp. introduced AGS in 1968

• • Computer Vision Corp. introduced CADDS in 1969Computer Vision Corp. introduced CADDS in 1969

--Personal Computer (PC) AutoDESK (for low-end user)--Personal Computer (PC) AutoDESK (for low-end user)

AutoDESK Corp. introduced AutoCAD for 2D CAD system in AutoDESK Corp. introduced AutoCAD for 2D CAD system in

later 1970'slater 1970's

AutoCAD R 12, and R13 C4 in 1996AutoCAD R 12, and R13 C4 in 1996

AutoDESK Collection, AutoCAD, AutoVision, Desiger, 3D studioAutoDESK Collection, AutoCAD, AutoVision, Desiger, 3D studio

Mechanical Desktop – parameter based systemMechanical Desktop – parameter based system



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--Integrated and knowledge-based CAD/CAE/CAM System --Integrated and knowledge-based CAD/CAE/CAM System

(for high-end user)(for high-end user)

I-DEAS/Pro-E/UG/CATIAI-DEAS/Pro-E/UG/CATIA

--Mid-range solid modeler--Mid-range solid modeler

• • SolidWorks, Solid EdgeSolidWorks, Solid Edge



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CAD Used as a Design Assistant ToolCAD Used as a Design Assistant Tool

Basic level - to assist in draftingBasic level - to assist in drafting

- Produce 2D engineering drawing and diagram- Produce 2D engineering drawing and diagram

- CAD is only used for - CAD is only used for Computer-Aided DraftingComputer-Aided Drafting

Advantages: Advantages:

ProductivityProductivity - short period of design and lower cost of - short period of design and lower cost of

design work.design work.

Accuracy Accuracy - improvements of product quality.- improvements of product quality.

ConsistencyConsistency - national standards, in-house standards. - national standards, in-house standards.

CAD Used as a Design Assistant ToolCAD Used as a Design Assistant Tool

Basic level - to assist in draftingBasic level - to assist in drafting

- Produce 2D engineering drawing and diagram- Produce 2D engineering drawing and diagram

- CAD is only used for - CAD is only used for Computer-Aided DraftingComputer-Aided Drafting

Advantages: Advantages:

ProductivityProductivity - short period of design and lower cost of - short period of design and lower cost of

design work.design work.

Accuracy Accuracy - improvements of product quality.- improvements of product quality.

ConsistencyConsistency - national standards, in-house standards. - national standards, in-house standards.


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Advanced level - to assist in design by 3D modelingAdvanced level - to assist in design by 3D modeling

o wireframe model, began to link with CAM and CAEwireframe model, began to link with CAM and CAE

o 3D surface model, shading for image3D surface model, shading for image

o 3D solid model, completed information and real-photo image3D solid model, completed information and real-photo image

o 3D CAD modeling for visualization - CAD/Design Vision3D CAD modeling for visualization - CAD/Design Vision

o 3D CAD modeling for analysis - CAD/CAE and FEA3D CAD modeling for analysis - CAD/CAE and FEA

o 3D CAD modeling for prototyping - CAD/RP&M3D CAD modeling for prototyping - CAD/RP&M

o 3D CAD modeling for manufacturing - CAD/CAM/CNC, CAD/CAPP3D CAD modeling for manufacturing - CAD/CAM/CNC, CAD/CAPP

o 3D CAD modeling for simulation - CAD/Real Physical Model3D CAD modeling for simulation - CAD/Real Physical Model

o 3D CAD modeling for animation - CAD/Real Physical Model3D CAD modeling for animation - CAD/Real Physical Model

Advanced level - to assist in design by 3D modelingAdvanced level - to assist in design by 3D modeling

o wireframe model, began to link with CAM and CAEwireframe model, began to link with CAM and CAE

o 3D surface model, shading for image3D surface model, shading for image

o 3D solid model, completed information and real-photo image3D solid model, completed information and real-photo image

o 3D CAD modeling for visualization - CAD/Design Vision3D CAD modeling for visualization - CAD/Design Vision

o 3D CAD modeling for analysis - CAD/CAE and FEA3D CAD modeling for analysis - CAD/CAE and FEA

o 3D CAD modeling for prototyping - CAD/RP&M3D CAD modeling for prototyping - CAD/RP&M

o 3D CAD modeling for manufacturing - CAD/CAM/CNC, CAD/CAPP3D CAD modeling for manufacturing - CAD/CAM/CNC, CAD/CAPP

o 3D CAD modeling for simulation - CAD/Real Physical Model3D CAD modeling for simulation - CAD/Real Physical Model

o 3D CAD modeling for animation - CAD/Real Physical Model3D CAD modeling for animation - CAD/Real Physical Model


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Example of CAD system-AutoCADExample of CAD system-AutoCAD

Icons (Tool Palette) Icons (Tool Palette) - Composite - Composite

set of most frequently used commandsset of most frequently used commands

Pull-Down Menu(Menu Bar)Pull-Down Menu(Menu Bar) - Listed on the - Listed on the

menu bar, contain all the commands.menu bar, contain all the commands.

Screen Menu Screen Menu - Containing almost all the commands.- Containing almost all the commands.

Graphics Window Graphics Window - the place used to build up model.- the place used to build up model.

Status Line Status Line - Give you information about the current status of your - Give you information about the current status of your

modelmodel

Command Window Command Window - A place you and AutoCAD can talk to each other- A place you and AutoCAD can talk to each other

Example of CAD system-AutoCADExample of CAD system-AutoCAD

Icons (Tool Palette) Icons (Tool Palette) - Composite - Composite

set of most frequently used commandsset of most frequently used commands

Pull-Down Menu(Menu Bar)Pull-Down Menu(Menu Bar) - Listed on the - Listed on the

menu bar, contain all the commands.menu bar, contain all the commands.

Screen Menu Screen Menu - Containing almost all the commands.- Containing almost all the commands.

Graphics Window Graphics Window - the place used to build up model.- the place used to build up model.

Status Line Status Line - Give you information about the current status of your - Give you information about the current status of your

modelmodel

Command Window Command Window - A place you and AutoCAD can talk to each other- A place you and AutoCAD can talk to each other


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Computer Aided ManufacturingExample of CAD system-AutoCADExample of CAD system-AutoCADExample of CAD system-AutoCADExample of CAD system-AutoCAD


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University TEAGA Nasional Lecturer: Habeeb Al-Ani

Features of AutoCAD SystemsFeatures of AutoCAD Systems

- Command Entry Styles- Command Entry Styles

o Keyboard entryKeyboard entry

o Pull-down menusPull-down menus

o Screen MenusScreen Menus

o Table Menu and IconsTable Menu and Icons

- Geometric Entities and Entry Coordinates- Geometric Entities and Entry Coordinates

- Three parts of AutoCAD Commands- Three parts of AutoCAD Commands

DrawDraw - entities (line, arc, circle, pline etc.) - entities (line, arc, circle, pline etc.)

ConstructConstruct- manipulate of entities (copy, array, chamfer, fillet, mirror, etc.)- manipulate of entities (copy, array, chamfer, fillet, mirror, etc.)

Modify Modify - edit of entities (erase, trim, move, etc.)- edit of entities (erase, trim, move, etc.)

Features of AutoCAD SystemsFeatures of AutoCAD Systems

- Command Entry Styles- Command Entry Styles

o Keyboard entryKeyboard entry

o Pull-down menusPull-down menus

o Screen MenusScreen Menus

o Table Menu and IconsTable Menu and Icons

- Geometric Entities and Entry Coordinates- Geometric Entities and Entry Coordinates

- Three parts of AutoCAD Commands- Three parts of AutoCAD Commands

DrawDraw - entities (line, arc, circle, pline etc.) - entities (line, arc, circle, pline etc.)

ConstructConstruct- manipulate of entities (copy, array, chamfer, fillet, mirror, etc.)- manipulate of entities (copy, array, chamfer, fillet, mirror, etc.)

Modify Modify - edit of entities (erase, trim, move, etc.)- edit of entities (erase, trim, move, etc.)

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Tooling and FixturingTooling and Fixturing


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Computer Aided ManufacturingTooling and FixturingTooling and Fixturing


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JigsJigs


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Computer Aided ManufacturingTooling and FixturingTooling and Fixturing

The purposes of jigs and fixtures are widespread however The purposes of jigs and fixtures are widespread however

when used in mass production they have five key aspects:when used in mass production they have five key aspects:

oReduce the cost of productionReduce the cost of production

oMaintain consistent quality Maintain consistent quality

oSpeed production Speed production

oPrevent or reduce improper techniques Prevent or reduce improper techniques

oImprove the overall safety to the part, operator, and machine. Improve the overall safety to the part, operator, and machine.


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In metal cutting, a proper tool must be identified for any In metal cutting, a proper tool must be identified for any

operation. operation.

The technical aspect of the decision increases with the The technical aspect of the decision increases with the

increasing number of possible tool selections and W/P increasing number of possible tool selections and W/P

materials. materials.

Selection of tool material factors:Selection of tool material factors:

oGeometry and construction include setup characteristics.Geometry and construction include setup characteristics.

oThe material itself.The material itself.

oThe shape and size of the W/P.The shape and size of the W/P.

Tooling characteristicsTooling characteristics


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oThe design requirement.The design requirement.

oThe type of operationThe type of operation

Tooling characteristics .. Cont..Tooling characteristics .. Cont..

-For given setup-and-tool combination machining For given setup-and-tool combination machining

parameters Feed, Speed, and cutting depth must parameters Feed, Speed, and cutting depth must

be selectedbe selected

-Selection of cutting parameters still no easy task. Selection of cutting parameters still no easy task. Why?.Why?.

BecauseBecause the suggested data in handbooks are based on the suggested data in handbooks are based on

isolated laboratory tests using standard specimens. Many isolated laboratory tests using standard specimens. Many

restrictive factors such as restrictive factors such as rigidity of the setup, quality of rigidity of the setup, quality of

machine tool, force and powermachine tool, force and power are carefully controlled. are carefully controlled.


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Computer Aided Manufacturing Tooling characteristics .. Cont..Tooling characteristics .. Cont..

- Cutting environment determined by the site..Cutting environment determined by the site..

(machine tool, and fixtures on the factory floor is (machine tool, and fixtures on the factory floor is

often different from the environments encountered often different from the environments encountered

in laboratory tests). Whereas the performance is in laboratory tests). Whereas the performance is

strongly dependent on environment variables.strongly dependent on environment variables.


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1.1. ASM, defined the machinability / The relative ease for ASM, defined the machinability / The relative ease for

material to be machined. To the people engaged in a material to be machined. To the people engaged in a

particular set of operations, particular set of operations, MachinabilityMachinability has a clear has a clear

meaning such as, meaning such as, number of components produced per number of components produced per

hour or per tool.hour or per tool.

OrOr2.2. The relative ease in achieving surface or dimensional The relative ease in achieving surface or dimensional

specifications. specifications.

MachinabilityMachinability


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To determine the Mchinability of any product, the To determine the Mchinability of any product, the

researchers and manufacturers are applied evaluation researchers and manufacturers are applied evaluation

criteria in practice as follows: criteria in practice as follows:

Machinability.. Cont..Machinability.. Cont..

1.1. Tool lifeTool life

2.2. Limiting material-removal rateLimiting material-removal rate

3.3. Surface finish achieved Surface finish achieved

4.4. Chip controlChip control

5.5. Force and power consumptionForce and power consumption


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ASM, and many industry reports are indexes the results ASM, and many industry reports are indexes the results

of machinability tests.of machinability tests.

-Long-term absolute machinability standard became Long-term absolute machinability standard became

available in 1977 available in 1977 (ISO 3685-1977).(ISO 3685-1977).

-The ISO standard test indicates the relative merit of two The ISO standard test indicates the relative merit of two

or more work-tool combinations for a range of cutting or more work-tool combinations for a range of cutting

conditions. conditions.



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Machinability test requirementsMachinability test requirements


1.1. Mounted the specimen between two centers or Mounted the specimen between two centers or

chuck ad center.chuck ad center.

2.2. Length to diameter ratio less than 10 / 1.Length to diameter ratio less than 10 / 1.

3.3. Tool material HSS, P30, P10, K20, OR K10.Tool material HSS, P30, P10, K20, OR K10.

4.4. Four sets of machining conditions, intended to Four sets of machining conditions, intended to

cover everything from light to heavy roughing cover everything from light to heavy roughing

operations.operations.

5.5. At least four speed should be used that ideally At least four speed should be used that ideally

result in a tool life of 5, 10, 20, or 40 min. result in a tool life of 5, 10, 20, or 40 min. Lecturer: Dr. HABEEB ALANI University TENAGA NasionalLecturer: Dr. HABEEB ALANI University TENAGA Nasional

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Tool failure criteria for HSS Tool failure criteria for HSS


1.1. Catastrophic tool failure (i. e., breakage)Catastrophic tool failure (i. e., breakage)

2.2. 0.3mm average flank-wear land width if flank wear 0.3mm average flank-wear land width if flank wear

is even.is even.

3.3. 0.6mm maximum flank wear if flank wear is 0.6mm maximum flank wear if flank wear is

irregular, scratched, chipped, or badly grooved.irregular, scratched, chipped, or badly grooved.


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Influence of physical & mechanical properties of materials Influence of physical & mechanical properties of materials

on machinabilityon machinability


1.1. Material with high yield strength and work-hardening Material with high yield strength and work-hardening

ability requires more power input, exerts higher ability requires more power input, exerts higher

compression stress and in general generates higher compression stress and in general generates higher

temperature on the tool surface.temperature on the tool surface.

2. In addition to requiring a high-energy input 2. In addition to requiring a high-energy input

machining ductile material results in a poor surface machining ductile material results in a poor surface

finish.finish.


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Influence of physical & mechanical properties of materials Influence of physical & mechanical properties of materials

on machinabilityon machinability


3.3. Material with high-fracture toughness tends to Material with high-fracture toughness tends to

generate long chips that are hard to break.generate long chips that are hard to break.

4.4. Material with a high work-hardening capability Material with a high work-hardening capability

requires more energy on the share plane.requires more energy on the share plane.

5.5. Good thermal conductivity can reduce the temp. on Good thermal conductivity can reduce the temp. on

the tool surface.the tool surface.

6.6. Material that tends to react chemically with the tool Material that tends to react chemically with the tool

material at high temperature can destroyed tools. material at high temperature can destroyed tools. Lecturer: Dr. HABEEB ALANI University TENAGA NasionalLecturer: Dr. HABEEB ALANI University TENAGA Nasional

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Machinability Machinability

of :of :


Steels/Steels/ with very low carbon (0.15%C), have poor with very low carbon (0.15%C), have poor

machinability by all criteria such as: machinability by all criteria such as:

1.1. ductile.ductile.

2.2. chips trend to adhere to the tool surface.chips trend to adhere to the tool surface.

3.3. high strain generates more heat.high strain generates more heat.

4.4. More energy required.More energy required.

5.5. Surface finish not good.Surface finish not good.


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Computer Aided ManufacturingMachinability of .. Cont..Machinability of .. Cont..

Free-machining steels/ Free-machining steels/ are typically alloys of steel and are typically alloys of steel and

sulfur, lead, or some other suitable alloying agent.sulfur, lead, or some other suitable alloying agent.

The addition of 0.1 to 0.3 % S or 0.1 to 0.35% Pb or a The addition of 0.1 to 0.3 % S or 0.1 to 0.35% Pb or a

small amount of Bi (bismuth), Se (selenium), Te small amount of Bi (bismuth), Se (selenium), Te

(tellurium), and P (phosphorus) can generally reduce (tellurium), and P (phosphorus) can generally reduce

the following:the following:

1. Force. 5. surface finish and 1. Force. 5. surface finish and

2. Power input. chip control improved.2. Power input. chip control improved.

3. Tool-surface temperature.3. Tool-surface temperature.

4. Tool wear rate. 4. Tool wear rate.


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Stainless Steels/ Stainless Steels/ stainless steels have three major types stainless steels have three major types

of microstructure:of microstructure:

1. Austenitic.1. Austenitic.

2. Ferritic.2. Ferritic.

3. Martensitic.3. Martensitic.

All these materials have higher tensile strength and All these materials have higher tensile strength and

greater spread between yield and fracture strength greater spread between yield and fracture strength

than low alloy steels. than low alloy steels.


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The energy input and the temperature on the tool The energy input and the temperature on the tool

surface are also higher than in ordinary steels. Due surface are also higher than in ordinary steels. Due

their high alloy content, the stainless steel containt their high alloy content, the stainless steel containt

abrasive carbide phases. Both of these abrasive carbide phases. Both of these

characteristics produce faster tool wear.characteristics produce faster tool wear.

Stainless steel have several reducing the machinability Stainless steel have several reducing the machinability

because: because:

1. Strong work-hardening capability.1. Strong work-hardening capability.

2. Low thermal conductivity.2. Low thermal conductivity.

3. Chips tend to bond to the tool surface.3. Chips tend to bond to the tool surface.


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Cast iron / Cast iron / Flake graphite and spheroidal graphite cast Flake graphite and spheroidal graphite cast

irons have good machinability with respect to all irons have good machinability with respect to all

criteria. The graphite flakes and spheres initiate criteria. The graphite flakes and spheres initiate

fracture on the shear plane at frequent intervals. fracture on the shear plane at frequent intervals.

Machining of flake graphite and spheroidal graphite Machining of flake graphite and spheroidal graphite

cast irons has the following properties: cast irons has the following properties:

1. Low tool wear rate. 5. Good surface finish.1. Low tool wear rate. 5. Good surface finish.

2. High MRR.2. High MRR.

3. Low force.3. Low force.

4. Low power consumption.4. Low power consumption.


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Nickel-based alloys/ Nickel-based alloys/ Nickel based alloys are among the Nickel based alloys are among the

most difficult materials to machine, because of their most difficult materials to machine, because of their

very strong work-hardening capability and hard very strong work-hardening capability and hard

abrasive-carbide phases. At much lower speeds than abrasive-carbide phases. At much lower speeds than

cutting steels, the tool temperature can reach the cutting steels, the tool temperature can reach the

point at which plastic deformation and diffusion can point at which plastic deformation and diffusion can

take place. Because of this work hardening, the feed take place. Because of this work hardening, the feed

rate is very important ( when the feedrate too low, rate is very important ( when the feedrate too low,

machining through the work-hardened material will machining through the work-hardened material will

continue long time. continue long time.


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Aluminum Alloys/ Aluminum Alloys/ pure aluminum is highly ductile. The pure aluminum is highly ductile. The

chip ends adhere to the tool surface, where it chip ends adhere to the tool surface, where it

becomes stringy and can be hard to break. It is becomes stringy and can be hard to break. It is

difficult to achieve a good surface finish, espacially difficult to achieve a good surface finish, espacially

at low cutting speed. Aluminum alloys have a good at low cutting speed. Aluminum alloys have a good

machinability in almost all criteria.machinability in almost all criteria.

Cast-aluminum alloys with silicon can reduce the tool Cast-aluminum alloys with silicon can reduce the tool

life and also more economically machined at lower life and also more economically machined at lower

cutting speeds and feeds than other types of cutting speeds and feeds than other types of

aluminum alloys abrasive particles causes this aluminum alloys abrasive particles causes this

reasons. reasons. Lecturer: Dr. HABEEB ALANI University TENAGA NasionalLecturer: Dr. HABEEB ALANI University TENAGA Nasional

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Machinability of .. Cont..Machinability of .. Cont..

Copper and its Alloys/ Copper and its Alloys/ pure copper is similar to other pure copper is similar to other

pure metals and has poor machinability. Unlike other pure metals and has poor machinability. Unlike other

pure metals, however, copper with a very low alloy pure metals, however, copper with a very low alloy

content is widely used in electronic components and content is widely used in electronic components and

fittings. The cutting speed of these small-size fittings. The cutting speed of these small-size

components are usually limited by the spindle speed components are usually limited by the spindle speed

(up to 140-220 m/min).(up to 140-220 m/min).

Tool forces are very high due to the large contact area Tool forces are very high due to the large contact area

on the rake face and the low shear angle. Surface on the rake face and the low shear angle. Surface

finish & chip control can become a problem. For this finish & chip control can become a problem. For this

reason high conductivity coppers regarded as one of reason high conductivity coppers regarded as one of

most difficult materials to machine most difficult materials to machine

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