dr. salah gasim ahmed met 103 1 met 103 module 5 milling machines

Dr. Salah Gasim Ahmed MET 103 Dr. Salah Gasim Ahmed MET 103

11

MET 103MET 103Module 5Module 5

Milling MachinesMilling Machines


22

What is What is millingmilling

Milling is the process of machiningMilling is the process of machining

flat,flat,

curved,curved,

or irregular surfacesor irregular surfaces by feeding the workpiece against a by feeding the workpiece against a rotating cutterrotating cutter containing a number of containing a number of cutting edgescutting edges.. A milling machine uses on or more A milling machine uses on or more revolving cutters to shape a work piece.revolving cutters to shape a work piece.


33

Types of milling machines:Types of milling machines:

Vertical milling machinesVertical milling machines– Turret (head can be tilted or swiveled)Turret (head can be tilted or swiveled)– Fixed head (head can not be tilted or swiveled)Fixed head (head can not be tilted or swiveled)

Horizontal milling machinesHorizontal milling machines– Plain horizontal milling machines (table is fixed Plain horizontal milling machines (table is fixed

at right angle to the knee)at right angle to the knee)– Universal milling machines (the table can be Universal milling machines (the table can be

pivoted in a horizontal plane)pivoted in a horizontal plane) Milling machines for special Milling machines for special

purposespurposes

Vertical Milling machine

Base

Spindle

Milling head

Ram

Column

Table

Knee

Saddle

Base

SaddleTable

Spindle

Milling head Ram

Column

Knee


66

Horizontal milling Horizontal milling machinemachine

BaseBase

ColumnColumn

RamRam

SpindleSpindle

Arbor Arbor SupportSupport

SaddleSaddle

KneeKnee

TableTable

ColumnSaddle

Table

SpindleArbor support

Base

Ram(or over arm)

Knee

Universal Milling machine

Vertical milling attachment


99

Milling machine attachment and Milling machine attachment and accessoriesaccessories

There are three classes of There are three classes of accessories:accessories:

1.1. Those which increase the Those which increase the versatility of the milling machine versatility of the milling machine e.g.:e.g.:

– Vertical milling attachmentVertical milling attachment– Slotting attachmentSlotting attachment

2.2. Those which holds the cutterThose which holds the cutter

3.3. Those which holds the work pieceThose which holds the work piece


1010

Cutter holding devices:Cutter holding devices:ArborArbor•Used for mounting the cutterUsed for mounting the cutter•It is held in the main spindle by a draw bolt It is held in the main spindle by a draw bolt •The outer end is supported by the arbor The outer end is supported by the arbor supportsupport•The cutter is positioned on the arbor by The cutter is positioned on the arbor by collarscollars

Collet adaptorCollet adaptor•It is held in the spindle the same manner as It is held in the spindle the same manner as the arborthe arbor•It is used for mounting tools with taper shankIt is used for mounting tools with taper shank

Quick change adaptorQuick change adaptor•Used for holding wide range of cutting toolsUsed for holding wide range of cutting tools

Arbor installationArbor installation

Spring colletSpring collet

Quick-change adaptor and tool Quick-change adaptor and tool holderholder

chuck

Collet chuck

1414

The most common types are:The most common types are:

1.1. VisesVises

2.2. V-blocksV-blocksMainly used for round worksMainly used for round works

3.3. Angle platesAngle platesThey are used for large works or special They are used for large works or special shapesshapes

4.4. FixturesFixturesThey are made to hold a particular work pieceThey are made to hold a particular work piece

5.5. Indexing head (dividing head)Indexing head (dividing head)It permits the cutting of gears, ratchets, bolt It permits the cutting of gears, ratchets, bolt headsheads

6.6. ClampsClamps

Work holding devices:Work holding devices:

VisesVises

1.1. Plain visePlain vise Jaws parallel or at right angle to the spindle axisJaws parallel or at right angle to the spindle axis2.2. Swivel base vise Swivel base vise it can swivel in a horizontal planeit can swivel in a horizontal plane3.3. Universal viseUniversal vise it can swivel in a horizontal plane,360it can swivel in a horizontal plane,36000, and , and

can be tilted 0 – 90can be tilted 0 – 9000 in a vertical plane in a vertical plane

ClampsClampsWhen work can not be held in a vise or a When work can not be held in a vise or a fixture it is clamped on the table. Here fixture it is clamped on the table. Here are some types of clamps:are some types of clamps:

– Straight clampStraight clamp

– Finger clampFinger clamp

– Double finger clampDouble finger clamp

– Screw clampScrew clamp

– U-clampU-clamp

– Goose neck clampGoose neck clamp

– Universal clampUniversal clamp

Indexing headIndexing head

Milling cuttersMilling cuttersThere many types of milling cutter. There many types of milling cutter. Here are some examples:Here are some examples:

Plain milling cutterPlain milling cutterPlain slitting cutterPlain slitting cutterShell milling cutterShell milling cutterSide milling cutterSide milling cutterEnd milling cutterEnd milling cutterGear milling cutterGear milling cutterT-slotting cutterT-slotting cutterDove-tail slotting cutterDove-tail slotting cutter

Cutting speeds, feeds and depth Cutting speeds, feeds and depth of cut:of cut:

Factors for determining speed (rpm)Factors for determining speed (rpm) Type of work materialType of work material Cutter materialCutter material Diameter of cutterDiameter of cutter Surface finishSurface finish Depth of cutDepth of cut Rigidity of machine and work setupRigidity of machine and work setup

The spindle The spindle speedspeed

(inch)(inch)

(metric)(metric)

The Value of CS is taken from table(1)The Value of CS is taken from table(1)

d

4x×CS=rpm

d

320×CS=rpm

MaterialMaterialHigh speed steel cutterHigh speed steel cutter Carbide cutterCarbide cutter

ft/minft/min m/minm/min ft/minft/min m/minm/min

Machine steelMachine steel 8080 2525 200200 6060

Tool steelTool steel 6565 1919 160160 5050

Cast iron Cast iron 7070 2020 160160 5050

BronzeBronze 9090 3030 300300 9090

AluminiumAluminium 750750 225225 15001500 225225

Table (1) Milling Machine Cutting SpeedsTable (1) Milling Machine Cutting Speeds

Milling Milling feedfeed

Feed = N x cpt x rpmFeed = N x cpt x rpm Where,Where,

– N: Number of teeth in milling cutterN: Number of teeth in milling cutter– cpt: chip per teeth for particular cutter, cpt: chip per teeth for particular cutter,

see table (2).see table (2).– rpm revolution per minute of the cutterrpm revolution per minute of the cutter

MaterialMaterial

Side millSide mill End millsEnd mills Plain helical millsPlain helical mills

InchesInchesMillimetMillimet

ererInchInch

MillimetMillimeterer

InchesInchesMillimetMillimet

erer

Machine steelMachine steel .007.007 0.180.18 .006.006 0.150.15 .010.010 0.250.25

Tool steelTool steel .005.005 0.130.13 .004.004 0.100.10 .007.007 0.180.18

Cast iron Cast iron .007.007 0.180.18 .007.007 0.180.18 .010.010 0.180.18

BronzeBronze .008.008 0.200.20 .009.009 0.230.23 .011.011 0.280.28

AluminiumAluminium .013.013 0.330.33 .011.011 0.280.28 .018.018 0.460.46

Table (2) Recommended Feed Per Tooth(High-Speed Steel Cutters)

Table (1) Milling Machine Cutting SpeedsTable (1) Milling Machine Cutting Speeds

MaterialMaterial

High speed steel High speed steel cuttercutter

Carbide cutterCarbide cutter





BronzeBronze 9090 3030 300300 9090

AluminiumAluminium 750750 225225 15001500 225225Table (2) Recommended Feed Per Tooth (HSS CuttersTable (2) Recommended Feed Per Tooth (HSS Cutters)

MaterialMaterial


InchesInches MillimeterMillimeter InchInch MillimeterMillimeter InchesInches MillimeterMillimeter




BronzeBronze .008.008 0.200.20 .009.009 0.230.23 .011.011 0.280.28







BronzeBronze 9090 3030 300300 9090



2424






BronzeBronze 9090 3030 300300 9090


MaterialMaterial


InchesInches MillimeterMillimeter InchInch MillimeterMillimeter InchesInches MillimeterMillimeter




BronzeBronze .008.008 0.200.20 .009.009 0.230.23 .011.011 0.280.28


Safety precautions for milling Safety precautions for milling machinesmachines

2525

1.1. Wear safety gogglesWear safety goggles2.2. Clean and dry the table before mounting the work Clean and dry the table before mounting the work

holding deviceholding device3.3. Clean and dry the holding device and work pieceClean and dry the holding device and work piece4.4. Mount the work piece securelyMount the work piece securely5.5. Select and mount the proper cutter to revolve in Select and mount the proper cutter to revolve in

the proper directionthe proper direction6.6. Clean and dry arbor cutter and collarsClean and dry arbor cutter and collars7.7. Use only correctly fitting wrenches on the machineUse only correctly fitting wrenches on the machine8.8. Tighten or loosen the arbor nut only with the Tighten or loosen the arbor nut only with the

arbor support in place (otherwise the arbor may arbor support in place (otherwise the arbor may bend)bend)

9.9. Use the proper spindle speed, feed and depth of cutUse the proper spindle speed, feed and depth of cut

10.10.Make certain that the table holding device and Make certain that the table holding device and work piece will clear the arbor and its support work piece will clear the arbor and its support during the cut.during the cut.

11.11.Disengage the manual feed hand wheel when Disengage the manual feed hand wheel when automatic feed is to be used.automatic feed is to be used.

12.12.Make sure that unauthorized persons are outside Make sure that unauthorized persons are outside the safety zone of the machine when it is started.the safety zone of the machine when it is started.

13.13.Keep clear of the revolving cutterKeep clear of the revolving cutter14.14.Stop the cutter to remove chips and use a brush Stop the cutter to remove chips and use a brush

for chip removalfor chip removal15.15.Release the automatic feed control when the job Release the automatic feed control when the job

is completedis completed..16.16.Keep floor free of chips , oil and greaseKeep floor free of chips , oil and grease17.17.When you finish working return all tools, When you finish working return all tools,

accessories and brush the machine free of chips.accessories and brush the machine free of chips.


2727

Thank YouThank You

dr. salah gasim ahmed met 103 1 met 103 module 5 milling machines

Documents