Bruce Mayer, PE Licensed Electrical & Mechanical Engineer [email protected]

[email protected] • ENGR-11_Lec-09_Chp6_Manufacturing_Selection.ppt1

Bruce Mayer, PE Engineering-11: Engineering Design

Bruce Mayer, PELicensed Electrical & Mechanical Engineer

[email protected]

Engineering 11

Manufacturing

Processes



Select Manufacturing Processes Manufacturing process decisions Deformation processes Casting processes Sheet metalworking Polymer processing Machining Finishing/Joining Assembly Material-Compatibilities & Process-Capabilities Material costs, Tooling costs, Processing costs



Make a Mountain Bike Select Processes to Manufacture a Bike

TopTube

RearDerailleur

Front Brake

Rear Brake

SaddleSeatPost

Pedal

Handle Bar

DownTube

Fork

(Courtesy of Trek Bicycle, 2002)



Manufacturing Process Decisions How to choose the specific manufacturing

processes? How do the selected materials influence the

choice of manufacturing processes? Would product function or performance

issues influence the choice of processes? What criteria should be used to select

processes? What are the Priority of the Criteria? Who makes the final decisions?



Design for Manuf (DFM) Guidelines Keep Functional & Physical

Characteristics as SIMPLE as Possible• Simple & Sturdy parts are Easier to Make,

and have Higher Reliability Design for the

LOWEST COST Production Method• Critical for

HI-VOLUME Parts



Design for Manuf (DFM) Guidelines Design for the Minimum Number for

Processing Steps (what’s a “step”?)• Try to ELIMINATE Steps thru Thoughtful

Product Design Specify Tolerances NO TIGHTER than

Actually Needed• OverToleranced Design leads to Increased

Cost thru– UnNeeded Processing Efforts– “False Positive” Scrap



Part-Processing Sequence Primary Process alter the (“raw”)

material’s basic shape or form. e.g., • Casting• Rolling• Forging• Drawing• Molding• Extruding

• That is, take a “bolb” of material and give it a basic shape; e.g.– Angle Iron– Tube/Pipe– Sheet/Plate



Part-Processing Sequence Secondary Process add or remove

geometric features from the basic forms alter the (“raw”) material’s basic shape or form. e.g.,• Machining of a brake drum

casting (flat surfaces)• Drilling/punching of refrigerator

housings (sheet metal)• Trimming of

injection molded part “flash”



Part-Processing Sequence Tertiary Process surface treatments.

e.g., • Polishing• Painting• Heat-Treating• Joining• Plating• Anodizing• Thin Film Coating



Process Selection Criteria Compatibility with Selected Materials Dimensional Accuracy and Tolerance Size & Weight Capacity Lead Time Min/Max Production Quantities

Surface Finish Need for Post-Process Operations

• e.g., Heat Treating



Cost Factors Influence of Special Desired Features

• e.g., Threaded Inserts, DoveTail Grooves Materials Availability Need for Special Tooling PostProcess Finish Operations

Special Handling Equipment Special Inspection Equipment Yield

• i.e., Scrap Rate



Manuf Process Classifications

E xtrus ionFo rg ingR o llingB ar draw ingW ire draw ing

D eform a tion

C en tri fu galD ie ca st ingInv estm entPerm anen t m o ldSan d ca s ting

C as ting

B en d ingB lan k ingD raw ingP u nch ingS h earingS p in n ing

S hee tM etal

B lo w m old ingC as t ingC o m press ion m o ld ingE xtru s ionIn jec tion M old ingT he rm o form ingT ran sfe r m old ing

Po lym erP rocesses

B oringD ril lingFac ingG rind ingM ill ingP lan ingT urn ingSaw ingE C M , E D M

M achin ing

A n od iz ingH o n ingP ain tingP la t ingP o lish ing

F in ish ing

A utom atedB o n d in gB raz ingM anu alR ive tingS o lde r ingW eld ing

A ssem bly

M anu fac tu ringProcesses



Deformation Processes Rolling Extrusion

Drawing Forging

Rolling

Plastic deformation

Rollers in compression

thick slab

thin sheet



Roll To Different Final Shape

slab

bloom

billet

sheet or coil

bar or rod

structural

ingot



Extrusion & Drawing Extrusion Drawing

Ram

OutPutCross

Sections

Extrusion Die

BilletPulling force

OutPutCross

Sections

Drawing Die

Billet



Forging (Closed Die Version)

Blockedpreform

Gutter

Ram pressure

Flash



Casting Processes Sand Casting Die Casting Investment

(a.k.a. “LostWax”) Casting



Sand Casting

Core Riser

Sprue

Runner

Drag

Flask

Cope

Gate

Partingline



Die Casting

Parting line

Plunger

Sprue

Moving die

Stationary die

Ejector pins

Moltenmetal



Investment Casting

Wax patternis cast

Wax removedby melting Molten metal

solidifies in cast Ceramic mold is removed

Ceramic mold(hardened slurry)4-part pattern tree



SheetMetal Fabrication Drawing Punching Shearing Spinning Bending Blanking

http://www.custompartnet.com/wu/images/sheet-metal/fine-blanking.png



Deep Metal Drawing

http://www.custompartnet.com/wu/images/sheet-metal/deep-drawing-sequence.png



Metal Spinning



PolyMer Processes Compression

Molding Blow Molding Injection molding Transfer Molding Reaction Injection

Molding (RIM)



Blow

Molding

http://www.custompartnet.com/wu/images/blow-molding/blow-molding.png



Injection Molding



Compression Molding

http://www.custompartnet.com/wu/images/thermoforming/mechanical-forming.png



Transfer Molding

Charge

Ram

Heatedmold

Sprue

Part

Ram pressure



Machining Processes

E x tru sionF o rg ingR o ll ingB a r d raw ingW ire d raw ing

D eform a t ion

C e n trifug alD ie ca s t ingInvestm entP e rm a ne n t m o ldS an d cas t ing

C a st ing

B e nd ingB lan k ingD raw ingPu nch in gSh ear ingSp in n ing

Sh ee tM e tal

B low m o ld ingC a st ingC om press io n m o ld ingE x trus ionIn je c tion M old ingT h erm oform ingT ran sfe r m o ld ing

Po ly m erP roce sses

B o r ingD ril lingFa c in gG rind ingM ill ingP la n ingT u rn ingSa w ingE C M , E D M

M ac hin ing

A no d iz ingH on ingPa in t ingP la tingPo lish ing

F in ish ing

A utom atedB o nd ingB raz ingM an u alR ive t ingSo ld er ingW e ld ing

A ssem b ly

M anu fac tu ringPro cesses



Machining Material Removal Sawing ≡ using a toothed blade. Milling ≡ form a flat surface by a rotating cutter tool. Planing ≡ using a translating cutter as workpiece feeds. Shaping ≡ form a translating workpiece using a stationary

cutter. Boring ≡ increasing diameter of existing hole by rotating the

workpiece. Drilling ≡ using a rotating bit forming a cylindrical hole. Reaming ≡ to refine the diameter of an existing hole. Turning ≡ form a rotating workpiece. Facing ≡ form turning workpiece using a radially fed tool. Grinding ≡ form a surface using an abrasive spinning wheel. Electric Discharge Machining ≡ by means of a spark.



Surface Finish Capability



Finishing Processes

E xtrus ionFo rg ingR o llingB a r d raw ingW ire d raw ing

D e form at ion

C e n trifu galD ie ca s t ingIn ve stm e ntPe rm a ne n t m o ldSa nd c as t ing

C a st ing

B en d ingB la nk ingD raw ingP un ch ingS he ar ingS p inn ing

She e tM e tal

B lo w m o ld ingC a st ingC om pre ss io n m o ld ingE x trus ionIn je c tion M o ld ingT h erm oform ingT ran sfe r m olding

P o lym erPro cesses

B or ingD ri l lingFac in gG r ind ingM ill ingP la n ingT urn ingSaw ingE C M , E D M

M ac hin ing

A n od iz ingH o ningP a in tingP la t ingP o l ish ing

F in ish ing

A utom atedB on d ingB raz ingM anu alR ive tingS o lde r ingW eld ing

A ssem bly

M anu fac tu r ingP rocesses



Anodizing



Assembly Joining

E x trus ionFo rg ingR o l l ingB a r d ra w ingW ire d raw ing

D eform a tion

C en tri fug alD ie cast ingInvestm entP erm anen t m o ldS and cas t ing

C a s ting

B end ingB lank ingD raw ingP un ch ingS hear ingS pinn ing

S he e tM etal

B low m old ingC astingC om press io n m o ld ingE x trus ionIn je c tion M o ld ingT h erm o form ingT ransfe r m o ld ing

P o lym erP ro cesses

B or ingD ri l lingF ac ingG rind ingM ill ingP lan ingT u rn ingS aw ingE C M , E D M

M ach in ing

A nod iz ingH on ingP a in tingP la t ingP ol ish ing

F in ish ing

A utom atedB ond ingB raz ingM an ualR iv e tingS o ld e ringW e ld ing

A ssem bly

M an ufac tu r ingP ro cesses



Gas Shielded Arc Welding

MIG (Metal Inert Gas)• a.k.a., Gas Metal Arc

Welding (GMAW)• METAL Wire Electrode

CONSUMED

TIG (Tungsten Inert Gas)• a.k.a., Gas Tungsten Arc

Welding (GTAW)• TUNGSTEN Electrode

NOT Consumed



Matls & Manuf Compatibility

Material Properties

ManufacturingProcesses

COMPATIBLEmaterials & processes



Material-Process CompatibilityME 488 Design for Manufacture & Assembly Materials Compatibility

Processes Shap

e A

ttrib

utes

Cas

t Iro

n

Car

bon

Stee

l

Allo

y S

teel

Sta

inle

ss S

teel

Alu

min

um &

allo

ys

Cop

per

& al

loys

Zinc

& a

lloys

Mag

nesi

um &

allo

ys

Tita

nium

and

allo

ys

Nic

kel &

allo

ys

Ref

ract

ory

met

als

Ther

mop

last

ics

ther

mos

ets

Solidification sand castinginvestment castingdie castinginjection moldingstructural foamblow molding - extrblow molding - injrotational molding

Bulk impact extrusionDeformation cold heading

closed die forgingpowder metalhot extrusionrotary swaging

Metal machined from stockRemoval ECM

EDM

Profile Generation Wire EDM

Sheet sheet metal bendingForming thermoforming

metal spinning© R. J. Eggert, BSU (Based on data from Boothroyd, Dewhurst & Knight) pg 47 revision 9/02/03

Legend Normal practiceLess commonNot applicable



Manufacturing Costs

Total Manufacturing Cost = Material + Tooling + Processing

raw mat’ls molds labor fixtures electricity jigs supplies tool bits O/H

(deprec.)

TMC = M + T + P (6.1)



Material Cost per PartLet M = total materials costs (raw, bulk) q = production quantity

Then material costs per part, cM is cM = M/q = (cost/weight x weight) / number of

parts

Let’s reorganize the variables in the equation above

cM = [cost/weight] [weight/number of parts] = (cost/weight) (weight/part), and therefore

cM = cost/part



Material Cost per Part (cont.)Let cw = material cost per unit weight, and wp = weight of finished part ww= weight of wasted material (the scrap) = Scrap-to-Useful Ratio → [wasted material weight]/[finished weight] = ww / wpThen the material cost per part, cM is

cM = cw (wp + ww ) = cw (wp + wp ) (6.2)

cM = cw wp (1+ ) (6.3)

e.g. sand casting cM = ($1/lb)(1lb/part)(1+.05) = $1.05/part



Tooling Cost per Part

Let T= total cost of molds, fixtures per production run q = number of parts per run

Then cT= T/q (6.4)

e.g. sand casting cT = ($10,000/run) / (5000 parts/run) = $2.00/part



Processing Cost per Part

Letct = cost per hour, (machine rate + labor)t = cycle time (hours per part)

then cP = ct t (6.5)

e.g. sand casting cP = ($30/hr) (0.3 hrs/part) = $9/part



TOTAL Cost per Part

Cost per part, c = cM + cT + cP

c = cw wp (1+ ) + T/q + ct t (6.6)

e.g. sand castingc = $1.05 + $2.00+ $9.00c = $12.05 / part



Example 5000 Part Run Alternative A B C Mfg. Process Sand casting Injection molding Machining

Material Aluminum alloy ABS Bronze alloy Part weight (lb) 1 3 2

alpha 0.05 0.01 0.2 Material cost ($/lb), cw 1 0.25 0.75

Tooling cost ($), T 10000 35000 1500 Production quantity, q 5000 5000 5000 Cycle time (hrs/part), t 0.3 0.03 0.6

Machine rate ($/hr) 30 100 75 Part cost ($/part) 12.05 10.7575 47.1

$45 of Bronze Part is due to Machining



Run Volume Sensitivity

1

10

100

1000

0 1000 2000 3000 4000 5000 6000

Production quantity

Cos

t ($/

part

)

A B C

A ≡ Sand Casting

B ≡ Inj. Molding C ≡ Machining



How to Lower Part Cost In Cost Eqn Minimize the SUM of Terms

c = cw wp (1+ ) + T/q + ct t (6.6)

1) purchase less expensive materials,2) keep our finished part weight low3) produce little manufactured waste (scrap,

flash, etc.)4) design simple parts that require

less expensive tooling 5) make many parts per production run

(i.e., use large quantities between ReTooling)6) choose a manufacturing process that has a

low-cycle-time & low-cost-per-hour



All Done for Today

ElectroChemicalMachining



Bruce Mayer, PERegistered Electrical & Mechanical Engineer

[email protected]

Engineering 11

Appendix



ElectroPolishing Benefits of Electropolishing - Electropolishing produces a number of favorable

changes in a metal part which are viewed as benefits to the buyer. All of these attributes translate into selling advantages depending upon the end use of the product. These include: • Brightening • Burr removal • Total passivation • Oxide and tarnish removal • Reduction in surface profile • Removal of surface occlusions • Increased corrosion resistance • Increased ratio of chromium to iron • Improved adhesion in subsequent plating • Reduced buffing and grinding costs • Removal of directional lines • Radiusing of sharp edges • Reduced surface friction • Stress relieved surface • Removal of hydrogen

Electropolishing produces the most spectacular results on 300 series stainless steels. The resulting finish often appears bright, shiny, and comparable to the mirror finishes of "bright chrome" automotive parts. On 400 series stainless steels, the cosmetic appearance of the parts is less spectacular, but deburring, cleaning, and passivation are comparable.



ECM What is the Electrochemical Machining Process ? The process is based on Michael

Faraday's Law of electrolysis, which is normally used in the electro plating of metals. Electrochemical machining is the reverse of plating, the work-piece is made the anode, which is placed in close proximity to an electrode (cathode), and a high-amperage direct current is passed between them through an electrolyte, such as salt water, flowing in the anode-cathode gap. Metal is removed by anodic dissolution and is carried away in the form of a hydroxide in the electrolyte for recycling or recovery.

A major advantage of electrochemical machining is that it can be used as a de burring or machining process on any metal, no matter how hard or corrosion resistant it is, without creating any residual thermal or mechanical stress in the work-piece.

The ECD process produces smooth, burr free edges and ECF can produce smooth, three dimensional forms with a good surface finish in single plunge forming pass. The process is simple to operate and offers fast production rates for difficult to conventionally machine alloys, with low running and tooling costs.

ECM does not create any physical or thermal stress during machining and components may be machined either before or after heat treatment. Metal removal rates are approximately 60 cubic mm per minute per 1000 amperes DC current employed. Surface finish may be less than 0.4 microns for some materials. Otherwise difficult to conventionally machine alloys can be easily machined or de-burred by ECM.

Examples include the stainless steels, high performance and high temperature alloys such as Inconel, Rene, Hastelloy, Titanium, Waspalloy and the latest generation corrosion resistant nickel alloys such as 617 and Alloy 59.

Bruce Mayer, PE Licensed Electrical & Mechanical Engineer [email protected]

Documents

pe engineering

engineering designdesign

engineering designsp12

engineering designmake

engineering designpartprocess

processing costs

choice of processes

processing steps whats