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Machining Processes

Group #3

Erica Velarde, Sean CliftonDavid Pincus, Ruben Sosa

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Typical Parts Made with

These Processes

Machine Components

Enine !loc"s and eads

Parts $ith Comple% Shapes

Parts $ith Close &olerances

E%ternall' and (nternall' &hreaded Parts

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Products and Parts Made By

These Processes

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Alternative Processes

Precision Castin

Po$der Metallur'

Po$der (n)ection Moldin

*brasive Machinin

&hread Rollin

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The Turning Process

Using Engine Lathes +perate on all &'pes of

Materials

se of sinle-point tools

S"illed .abor

.o$ Production Rate

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Tool Geometry

Ra"e *nle

Side Ra"e *nle

Cuttin-Ede *nle

Relief *nle

/ose Radius

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Typical Lathe and Its VariousComponents

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Lathe Components

Bed: suall' made of cast iron0 Provides a heav'riid frame on $hich all the main components are

mounted0

• Ways1 (nner and outer uide railsn that are

precision machined parallel to assure accurac' ofmovement0

• Headstock: mounted in a fi%ed position on the

inner $a's, usuall' at the left end0 sin a chuc", it

rotates the $or"0• Gearbox: inside the headstoc", providin multiple

speeds $ith a eometric ratio b' movin levers0

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• Spindle: ole throuh the headstoc" to $hich barstoc" can be fed0

• Chuck: 3-)a$ 2self centerin or 4-)a$ 2independentto clamp part bein machined0

• ailstock: 5its on the inner $a's of the bed and canslide to$ards an' position the headstoc" to fit thelenth of the $or" piece0 *n optional taper turninattachment $ould be mounted to it0

• ailstock !uill1 as a Morse taper to hold a lathecenter, drill bit or other tool0

• Carriage: Moves on the outer $a's0 sed formountin and movin most the cuttin tools0

• Cross Slide: Mounted on the traverse slide of thecarriae, and uses a hand$heel to feed tools intothe $or"piece0

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• ool "ost: &o mount tool holders in $hich the cuttinbits are clamped0

• Co#pound $est: Mounted to the cross slide, it

pivots around the tool post0• %pron: *ttached to the front of the carriae, it has

the mechanism and controls for movin the carriaeand cross slide0

• &eed $od: as a "e'$a', $ith t$o reversin pinionears, either of $hich can be meshed $ith thematin bevel ear to for$ard or reverse the carriaeusin a clutch0

• Lead Scre': 5or cuttin threads0

• Split (ut: 6hen closed around the lead scre$, thecarriae is driven alon b' direct drive $ithout usina clutch0

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• !uick Change Gearbox: Controls the movement ofthe carriae usin levers0

• Steady $est: Clamped to the lathe $a's, it usesad)ustable finers to contact the $or"piece and alinit0 Can be used in place of tailstoc" to support lonor unstable parts bein machined0

• &ollo' $est: !olted to the lathe carriae, it usesad)ustable finers to bear aainst the $or"pieceopposite the cuttin tool to prevent deflection0

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Lathe Accessories

Carriae and Cross Slide Stops

Devices for &urnin Parts $ith Various &apers

Millin, Sa$in, Gear-Cuttin, and Grindin

*ttachments

Various *ttachments for !orin, Drillin, and

&hread Cuttin

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Typical Lathe and Its VariousComponents

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More Tool Geometry

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Lathe Operations

5orm &ools

!orin

Drillin

Partin

Groovin

&hread Cuttin 7nurlin

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Cutting Operations Perormedon a Lathe

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Above Left: Example of Boring Above Right: Example of Drilling

Below Left: Example of Threa Cutting Below Right: Example of!rooving

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Types o Lathes

!ench .athes

Special Purpose .athes

&racer .athes

*utomatic .athes

*utomatic !ar Machines

&urret .athes Computer-Controlled .athes

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Turret Lathe

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Computer!Controlled Lathe

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Things to "emem#er A#outMachining Parts on Lathes

&a"es considerable amount of time

ih Production Costs 6astes Material

/ot as Economical as 5ormin or Shapin

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Machining Processes

!orin, Drillin, Reamin, and &appin

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Boring and Boring

Machines

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$hat is Boring

Performed to enlare a hole made previousl'0

sed for circular internal profiles in hollo$

$or"pieces

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Boring Machines

Small pieces 8 lathe .are pieces 8 borin

mill ori9ontal vs Vertical

!orin mills Perform various

operations1 &R/(/G,5*C(/G, GR++V(/G,

C*M5ER(/G

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%ori&ontal Boring Mill

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Vertical Boring Mill

.are pieces can be

machined on a vertical

mill

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'ig Boring Machines

Vertical machines ih precision bearins

sed to ma"e )is and

fi%tures

!ein replaced b' C/C

borin machines

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Considerations

&hrouh holes, rather than blind holes,

should be specified0

Smaller lenth-bore diameter ratios

(nterrupted internal surfaces should be

avoided0

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(rilling) (rills) and

(rilling Machines

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$hat are %oles used *or+

&'pical for assembl' $ith fasteners i0e0 scre$s, bolts, rivets

6eiht reduction

Ventilation

*ccess to inside parts

*ppearance

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(rilling is a CommonProcess,,,

THE COST OF HOLE MAKING IS AMONG THE

HIGHEST MACHINING COSTS INAUTOMOTIVE ENGINE PRODUCTION

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Properties

!urrin on the bottom surface upon

brea"throuh re:uires further machinin

Diameters of holes are usuall' oversi9e ;ualit' of drill

&hermal properties

Reamin and honin improve dimensional

accurac'

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-tandard!Point Twist (rill

Point anle 2<<=-<3>de

.ip-relief anle 2?-<>de

Chisel-ede anle 2<@>-<3>de

eli% anle 2<>-3Ade

Diameter rane from A0>-<>Amm

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Other Types o (rills

Step Drill Produces @ or more different diameters

Core Drill Ma"es an e%istin hole larer

Counterborin B Countersin"in Produce depressions on the surface to

accommodate the heads of scre$sbolts

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More (rill Types

Center drill Produces small hole on the

end of a $or"piece

Spot drill Starts a hole at the desired

location

Spade drill Removable bits, produces

lare-diameter or deep holes iher stiffness 2absence of

flutes Straiht-flute drill Gun drill

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Gun (rill

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Trepanning

Removes a dis" to create a hole

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Material!"emoval "ate

)$$*+pi,-./01,( 2 3

PiD@ 4F cross sectional area

5 F the distance penetrated per revolution

/ F rotational speed

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General Trou#leshootingProblem Probable causes

Drill brea"ae Dull bit, chips cloin flutes, feed tohih, lip relief anle too small

E%cessive drill $ear Cuttin speed to hih, ineffective fluid,ra"e anle too hih, drill burned $hensharpened

&apered hole Drill misalined or bent, lips not e:ual

+versi9e hole Same as above, machine spindle loose,chisel ede not central, side force on$or"piece

Poor hole surface finish Dull bit, ineffective fluid, $eldin of$or"piece on drill marin, improperl'round drill, improper alinment

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"eaming and "eamers

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Considerations

Drillin should be perpendicular to the surface

(nterrupted holes should be avoided

ole bottoms should match standard drill point

anles &hrouh holes preferred to blind holes

Pree%istin holes or dimples help center the drill

!lind holes must be drilled deeper than subse:uent

reamin or tappin operations

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$hat is "eaming

*n operation used to ma"e an e%istin hole

dimensionall' more accurate andor to

improve surface finish

5or further accurac' and surface finish, holesma' be burnished, ground or honed 0

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. -teps to Accuracy

<0 Centerin

@0 Drillin

30 !orin

40 Reamin

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Tapping and Taps

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Tapping

Produces threads

Ma' be done b' hand

or machine

Chipless tappin is aprocess of internal

thread rollin

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Millin and Millin Machines

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Milling

&he Process of cuttin a$a'

material b' feedin a

$or"piece past a rotatin

multiple tooth cutter0

ll

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Types o Milling

h l ll

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Peripheral Milling

Peripheral Millin is $hen the cutter is loner than

the $idth of the cut0

a0"0a0- Slab Millin

&he a%is of the cutter is usuall' parallel to the $or"piece surface0

* Milli

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*ace Milling

the cutter is mounted on a spindle havin an

a%is of rotation perpendicular to the

$or"piece surface0

.eaves feed mar"s on the machined surface0

/ d Milli

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/nd Milling

&he cutter enerall' rotates on an a%is

vertical to the $or"piece0

(t can be tilted to machine tapered surfaces0

Cuttin teeth are located on both the endface of the cutter and the peripher' of the

cutter bod'0

Can produce a variet' of surfaces at an'depth0

C i l Milli

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Conventional Milling

a0"0a- p Millin

&he Direction of cutter rotation opposes the

feed motion0

Cli # Milli

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Clim# Milling

a0"0a0- Do$n Millin

&he direction of cutter rotation is the same as

the feed motion0

Oth T Milli

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Other Types o Milling

Straddle Millin

5orm Millin

Slottin and Slittin

ses circular cutters

T l h ld

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Tool holders

*rbor Cutters Mounted on an arbor

sed in peripheral, face, straddle and form

millin0

-h 0 T Milli

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-han0!Type Milling

Cutter and shan" are

one peice

( i d O ti

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(esign and OperatingGuidelines !asic cutters should be used as much as

possible0 *void e%pensive special cutters0

Chamfers should be specified instead of

radii0Chamfer-* furro$ or roove, as in a column0

*void internal cavities and poc"ets $ith sharp

corners0Due to the difficult' of doin them0

T #l h ti

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Trou#leshooting

&ool !rea"ae &ool material lac"s touhness,improper anles0

E%cessive &ool 6ear improper tool material, improper

tool fluids0

Rouh Surface 5inish 5eed per tooth too hih, toolchipped or $orn0

Chatter Mar"s (nsufficient stiffness of s'stem,

e%ternal vibrations0

!rea"out .ead anle too lo$, feed and

depth of cut too hih0

Milli M hi

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Milling Machines

5irst Millin Machine !uilt in <=@A b' Eli 6hitne'

C l d 1 t

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Column!and!1nee type

Most common millin machines0

B i C t

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Basic Components

6or" &able

Saddle

7nee

+verarm

ead

Bed T pe

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Bed Type

6or" table is mounted is mounted directl' on

the bed0

/ot versatile

ih Stiffness sed for hih production $or"

Other Milling Machines

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Other Milling Machines

Planer-&'pe Several heads and cutters able to mill different surfaces

Rotar'-&able+ne or more heads for face millin0

Computer /umerical Control

*ble to mill, drill, bore and tap $ith repetitive accurac'Profile Millin Machines

> a%es of movement0

Planning and -haping

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Planning and -haping

Plannin .are $or"pieces @>m H <>m

6or" piece is mounted on a table and travels bac" and

forth alon a straiht path0

Cuttin speeds can et up to <@A mmin $ith <>A hp

Shapin &ool does the movin

Small less than <m H @m

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introduction

!roachin and !roachin machines

Sa$in5ilin

Gear Manufacturin b' Machinin

Broaching and Broaching

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Broaching and Broachingmachines !roachin is a similar

techni:ue to shapin

$ith a lon multiple-

tooth cutter and is used

to machine internal ane%ternal surfaces0

!roachin is )ust as

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!roachin is )ust as

effective as

!orin

Millin

Shapin

Reamin

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!roachin machinesare ver' e%pensive but

these machines 'ield a

ver' hih :uantit' of

production runs0

ses a sinle passf fi i h d h

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for finished shapesor si9ed

Produces closetolerances and oodsurface finish

ses a multipointcuttin tool 2broach

as the rouhinand finishin teethon the same tool

-awing

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Sa$in is an old common operation datin bac" to

around <AAA !0C Sa$in is an efficient bul" removal process and can

produce near net shape materials

&he process $astes little material

Most common use of sa$s ac"sa$s

Circular sa$s

!and sa$s 5riction sa$in

-amples o various sawing

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-amples o various sawingoperations

%ac0saws

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%ac0sawsac"sa$s $ere developed in the <IJAKs0

Good for cuttin off bars, rods, and structuralshapes

Po$er hac"sa$s

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5ast

&he' $or" smoothl'

and efficientl' evenunder heav'-dut'

operation0 6ith normal

care these machines

are indestructible0

Circular sawing

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Circular sawing

Circular sa$in is a multipoint cuttin process in$hich a circular tool is advanced aainst a stationar'

$or"piece to sever parts or produce narro$ slots0

ses thin circular blades $ith teeth on peripher'

Rotatin blade is fed into a stationar' $or"piece

Produces a narro$ cut and a ood surface finish

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Circular sa$s alsocalled cold sa$s $hen

cuttin metal

&he' are used for hih

production rate sa$in

Cold sa$in is used in

industr' ver' commonl'

particularl' for cuttinlare crossed sections0

Diamond Sa$ !lades 5or Marble *nd .imestone

sa$ bladefor plastics

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&'pes of coldsa$inmachines

Band sa'

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ses a fle%ible steel band $ith a toothed ede

6or"pieces are fed into the cuttin ede on vertical

machines

Can produce straiht, irreular, or curved cuts

*riction sawing

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*riction sawing

6or"pieces are fed intoa continuousl' movin

band

Produces fine, accurate

$or"

(s a finishin operation

in $hich small amounts

of material are removed

Gear Manuacturing #y

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Gear Manuacturing #yMachining

Several processes for ma"in ears

5orm cuttin 2form-millin

Gear eneratin 2obbin, Shapin

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Gear millin ses a rotatin form

cutter

Gear blan"s are

inde%ed after each cut (s a lo$ production

process

Gear teeth areproduced individuall'

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Gear eneratin &his particular machine

removes over <? lb of==@@ steel from a <AA-

lb, <=-in0-diameter earin under <@ min

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Gear obbin (s a ear eneratin

process that uses a

helical hob cutter

Cuts several teeth on a

proressive basis

(s used for hih

production runs

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Gear shapin Cutters rotate in timed

relationship $ith the$or"piece

Produces internalears, e%ternal ears,and interal ear-pinionarranements

CuttingGearTeeth.mov

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