Presentation_11_9_05.ppt

7/25/2019 Presentation_11_9_05.ppt

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Machining Processes

Group #3

Erica Velarde, Sean CliftonDavid Pincus, Ruben Sosa



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



Products and Parts Made By

These Processes



Alternative Processes

Precision Castin

Po$der Metallur'

Po$der (n)ection Moldin

*brasive Machinin

&hread Rollin



The Turning Process

Using Engine Lathes +perate on all &'pes of

Materials

se of sinle-point tools

S"illed .abor

.o$ Production Rate



Tool Geometry

Ra"e *nle

Side Ra"e *nle

Cuttin-Ede *nle

Relief *nle

/ose Radius





Typical Lathe and Its VariousComponents



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



• 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



• 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



• !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



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



Typical Lathe and Its VariousComponents



More Tool Geometry



Lathe Operations

5orm &ools

!orin

Drillin

Partin

Groovin

&hread Cuttin 7nurlin



Cutting Operations Perormedon a Lathe



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

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



Types o Lathes

!ench .athes

Special Purpose .athes

&racer .athes

*utomatic .athes

*utomatic !ar Machines

&urret .athes Computer-Controlled .athes





Turret Lathe



Computer!Controlled Lathe



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





Machining Processes

!orin, Drillin, Reamin, and &appin



Boring and Boring

Machines



$hat is Boring

Performed to enlare a hole made previousl'0

sed for circular internal profiles in hollo$

$or"pieces



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



%ori&ontal Boring Mill



Vertical Boring Mill

.are pieces can be

machined on a vertical

mill



'ig Boring Machines

Vertical machines ih precision bearins

sed to ma"e )is and

fi%tures

!ein replaced b' C/C

borin machines



Considerations

&hrouh holes, rather than blind holes,

should be specified0

Smaller lenth-bore diameter ratios

(nterrupted internal surfaces should be

avoided0



(rilling) (rills) and

(rilling Machines



$hat are %oles used *or+

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

6eiht reduction

Ventilation

*ccess to inside parts

*ppearance



(rilling is a CommonProcess,,,

THE COST OF HOLE MAKING IS AMONG THE

HIGHEST MACHINING COSTS INAUTOMOTIVE ENGINE PRODUCTION



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'



-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





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







Gun (rill



Trepanning

Removes a dis" to create a hole



Material!"emoval "ate

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

PiD@ 4F cross sectional area

5 F the distance penetrated per revolution

/ F rotational speed



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



"eaming and "eamers



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



$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



. -teps to Accuracy

<0 Centerin

@0 Drillin

30 !orin

40 Reamin



Tapping and Taps



Tapping

Produces threads

Ma' be done b' hand

or machine

Chipless tappin is aprocess of internal

thread rollin





Millin and Millin Machines



Milling

&he Process of cuttin a$a'

material b' feedin a

$or"piece past a rotatin

multiple tooth cutter0

ll



Types o Milling

h l ll



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



*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



/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



Conventional Milling

a0"0a- p Millin

&he Direction of cutter rotation opposes the

feed motion0



Oth T Milli



Other Types o Milling

Straddle Millin

5orm Millin

Slottin and Slittin

ses circular cutters

T l h ld



Tool holders

*rbor Cutters Mounted on an arbor

sed in peripheral, face, straddle and form

millin0

-h 0 T Milli



-han0!Type Milling

Cutter and shan" are

one peice

( i d O ti



(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



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



Milling Machines

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

C l d 1 t



Column!and!1nee type

Most common millin machines0

B i C t



Basic Components

6or" &able

Saddle

7nee

+verarm

ead

Bed T pe



Bed Type

6or" table is mounted is mounted directl' on

the bed0

/ot versatile

ih Stiffness sed for hih production $or"

Other Milling Machines



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



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





introduction

!roachin and !roachin machines

Sa$in5ilin

Gear Manufacturin b' Machinin

Broaching and Broaching



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



!roachin is )ust aseffective as

!orin

Millin

Shapin

Reamin



!roachin machinesare ver' e%pensive butthese machines 'ield aver' hih :uantit' ofproduction runs0

ses a sinle passf fi i h d h



for finished shapesor si9ed

Produces closetolerances and oodsurface finish

ses a multipointcuttin tool 2broach

as the rouhinand finishin teethon the same tool

-awing



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



-amples o various sawingoperations

%ac0saws



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

Good for cuttin off bars, rods, and structuralshapes

Po$er hac"sa$s 5 t



5ast

&he' $or" smoothl'

and efficientl' evenunder heav'-dut'operation0 6ith normalcare these machines

are indestructible0

Circular sawing



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





Circular sa$s alsocalled cold sa$s $hencuttin metal

&he' are used for hih

production rate sa$in Cold sa$in is used in

industr' ver' commonl'particularl' for cuttin

lare crossed sections0

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

sa$ bladefor plastics



&'pes of coldsa$inmachines

Band sa'



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



*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 millin ses a rotatin form

cutter

Gear blan"s are

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

process

Gear teeth areproduced individuall'



Gear eneratin &his particular machine

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

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



Gear obbin (s a ear eneratin

process that uses ahelical hob cutter

Cuts several teeth on aproressive basis

(s used for hihproduction runs



"eerences



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http1$$$0ohiobroach0com http1$$$0broachinmachine0com

http1class0et0b'u0edumf<3Aprocessesme

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Presentation_11_9_05.ppt

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