Traditional Manufacturing Processes
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Traditional Manufacturing Processes - PowerPoint PPT Presentation

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Traditional Manufacturing Processes. Casting. Forming. Sheet metal processing. Powder- and Ceramics Processing. Plastics processing. Cutting. Joining. Surface treatment. Cutting. Processes that involve removal of material from solid workpiece. Sawing Shaping (or planing),

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Traditional Manufacturing Processes



Sheet metal processing

Powder- and Ceramics Processing

Plastics processing



Surface treatment

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Processes that involve removal of material from solid workpiece


Shaping (or planing),

Broaching, drilling,




Important concept: PROCESS PLANNING

Fixturing and Location

Operations sequencing

Setup planning

Operations planning

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A process to cut components, stock, etc.

Process character: Precision: [very low,, very high]; MRR: low

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A process to plane the surface of a workpiece (or to reduce part thickness

Process character: High MRR, medium Surface finish, dimension control

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Precise process for mass-production of complex geometry parts

(complicated hole-shapes)

Process character: High MRR, Very good surface, dimension control, Expensive

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Drilling, Reaming, Boring

Processes to make holes

Process character: High MRR, Cheap, Medium-high surface, dimension control

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Drilling basics

- softer materials  small point angle; hard, brittle material: larger point angle

- Length/Diameter ratio is large gun-drilling (L/D ratio ~ 300)

- Very small diameter holes (e.g. < 0.5 mm): can’t drill (why?)

- F drilled hole > F drill: vibrations, misalignments, …

- Tight dimension control: drill  ream

- Spade drills: large, deep holes

- Coutersink/counterbore drills: multiple diameter hole  screws/bolts heads

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Processes to make threads in holes

Process character: low MRR, Cheap, good surface, dimension control

Automated tapping

Manual tap and die set

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Grinding, Abrasive Machining

Processes to finish and smooth surfaces

Process character: very low MRR, very high surface, dimension control

1. To improve the surface finish of a manufactured part

(a) Injection molding die: milling manual grinding/electro-grinding.

(b) Cylinders of engine: turning  grinding  honing  lapping

2. To improve the dimensional tolerance of a manufactured part

(a) ball-bearings: forging  grinding [control: < 15 mm]

(b) Knives: forged steel  hardened  grinding

3. To cut hard brittle materials

(a) Semiconductor IC chips: slicing and dicing

4. To remove unwanted materials of a cutting process

(a) Deburring parts made by drilling, milling

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Processes to cut cylindrical stock into revolved shapes

Process character: high MRR, high surface, dimension control

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Versatile process to cut arbitrary 3D shapes

Process character: high MRR, high surface, dimension control

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Common vertical milling cutters




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Process Analysis

Fundamental understanding of the process  improve, control, optimize

Method: Observation  modeling  verification

Every process must be analyzed; [we only look at orthogonal 1-pt cutting]

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Modeling: Mechanism of cutting

Old model: crack propagation

Current model: shear

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Tool wear: observations and models

High stresses, High friction, High temp (1000C)  tool damage

Adhesion wear:

fragments of the workpiece get welded to the tool surface at high temperatures;

eventually, they break off, tearing small parts of the tool with them.


hard particles, microscopic variations on the bottom surface of the chips

rub against the tool surface

Diffusion wear:

at high temperatures, atoms from tool diffuse across to the chip;

the rate of diffusion increases exponentially with temperature;

this reduces the fracture strength of the crystals.

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Tool wear, Tool failure, Tool life criteria

  • Catastrophic failure (e.g. tool is broken completely)

  • VB = 0.3 mm (uniform wear in Zone B), or VBmax = 0.6 mm (non-uniform flank wear)

  • KT = 0.06 + 0.3f, (where f = feed in mm/revolution).

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Built-up edge (BUE)

Deposition, work hardening of a thin layer of the workpiece material

on the surface of the tool.

BUE  poor surface finish

Likelihood of BUE decreases with

(i) decrease in depth of cut,

(ii) increase in rake angle,

(iii) use of proper cutting fluid during machining.

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Process modeling: empirical results

Experimental chart showing relation of tool wear with f and V

[source: Boothroyd]

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Modeling: surface finish

Relation of feed and surface finish

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Analysis: Machining Economics

How can we optimize the machining of a part ?

Identify the objective, formulate a model, solve for optimality

Typical objectives: maximum production rate, and/or minimum cost

Are these objectives compatible (satisfied simultaneously) ?

Formulating model: observations  hypothesis  theory  model

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Analysis: Machining Economics..

Formulating model: observations  hypothesis  theory  model


A given machine, tool, workpiece combination has finite max MRR


Total volume to cut is minimum  Maximum production rate

Model objective:

Find minimum volume stock for a given part

-- Near-net shape stocks (use casting, forging, …)

-- Minimum enclosing volumes of 3D shapes


- minimum enclosing cylinder for a rotational part

- minimum enclosing rectangular box for a milled part


-- requires some knowledge of computational geometry

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Analysis: Machining Economics..

Model objective:

Find optimum operations plan and tools for a given part





Model: Process Planning

- Machining volume, tool selection, operations sequencing


- in general, difficult to optimize

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Analysis: process parameters optimization

Model objective:

Find optimum feed, cutting speed to [maximize MRR]/[minimize cost]/…


Higher feed  higher MRR

Finish cutting:

surface finish  feed

 Given surface finish, we can find maximum allowed feed rate

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Process parameters optimization: feed

Rough cutting:

MRR  cutting speed, V

MRR  feed, f

 cannot increase V and f arbitrarily

↑V  ↑ MRR; surface finish ≠ f(V); energy per unit volume MRR ≠ f(V)

Tool temperature  V, f; Friction wear  V; Friction wear ≠ f

For a given increase in MRR: ↑ V  lower tool life than ↑ f

Optimum feed: maximum allowed for tool [given machine power, tool strength]

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Process parameters optimization: Speed

Model objective:

Given optimum feed, what is the optimum cutting speed

 provided upper limits, but not optimum

Need a relation between tool life and cutting speed (other parameters being constant)

Taylor’s model (empirically based): V tn = constant

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Process parameters optimization: Speed

One batch of large number, Nb, of identical parts

Replace tool by a new one whenever it is worn

Total non-productive time = Nbtl

tl = time to (load the stock + position the tool + unload the part)

Nb be the total number of parts in the batch.

Total machining time =Nbtm

tm = time to machine the part

Total tool change time =Nttc

tc = time to replace the worn tool with a new one

Nt = total number tools used to machine the entire batch.

Cost of each tool = Ct,

Cost per unit time for machine and operator = M.

Average cost per item:

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Process parameters optimization: Speed

Average cost per item:

Let: total length of the tool path = L

t = tool life Nt = (Nb tm)/t Nt / Nb = tm / t

Taylor’s model Vtn = C’  t = C’ 1/n / V1/n = C/V1/n

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Process parameters optimization: Speed

Optimum speed (to minimize costs)

Optimum speed (to minimize time)

Average time to produce part:

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Process parameters optimization: Speed

Optimum speed (to minimize costs)

Optimum speed (to minimize time)

Average time to produce part:

load/unload time

tool change time

machining time

Substitute, differentiate, solve for V*

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Process Planning

The process plan specifies:


tools, path plan and operation conditions



possible machine routings


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Operation sequencing examples (Milling)

big-hole step  small hole


small holestep  big-hole


step  hole


hole  step

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Traditional Manufacturing Processes



Sheet metal processing

Powder- and Ceramics Processing

Plastics processing



Surface treatment

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Joining Processes

Types of Joints:

1. Joints that allow relative motion (kinematic joints)

2. Joints that disallow any relative motion (rigid joints)

Uses of Joints:

1. To restrict some degrees of freedom of motion

2. If complex part shape is impossible/expensive to manufacture

3. To allow assembled product be disassembled for maintenance.

4. Transporting a disassembled product is sometimes easier/feasible

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Joining Processes

Fusion welding: joining metals by melting  solidification

Solid state welding: joining metals without melting

Brazing: joining metals with a lower mp metal

Soldering: joining metals with solder (very low mp)

Gluing: joining with glue

Mechanical joining: screws, rivets etc.

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Flame: 3000C

Fusion welding

Oxy-acetylene welding

Arc welding



arc: 30,000C

Gas shielded arc welding





Ti, Mg,

Thin sections

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Fusion welding..

Deep, narrow welds

Aerospace, medical, automobile body panels

Plasma arc welding

Faster than TIW, slower than Laser

Nd:YAG and CO2 lasers, power ~ 100kW

Laser beam welding

Fast, high quality, deep, narrow welds

deep, narrow welds, expensive

Electron beam welding

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Solid state welding

Diffusion welds between very clean, smooth pieces of metal, at 0.3~0.5Tm

Cold welding (roll bonding)

coins, bimetal strips

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Ultrasonic wire bonder

25mm Al wire on IC Chip

Solid state welding..

Ultrasonic welding

Medical, Packaging, IC chips, Toys

Materials: metal, plastic

- clean, fast, cheap

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Resistance welding

Welding metal strips: clamp together, heat by current

Spot welding

Seam welding

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Tm of Filler material < Tm of the metals being joined

Furnace brazing

Torch brazing

Common Filler materials: copper-alloys, e.g. bronze

Common applications: pipe joint seals, ship-construction


Tin + Lead alloy, very low Tm (~ 200C)

Main application: electronic circuits

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Mechanical fasteners

(a) Screws (b) Bolts, nuts and washers (c) Rivets

(a) pneumatic carton stapler (b) Clips (c) A circlip in the gear drive of a kitchen mixer

Plastic wire clips

Plastic snap-fasteners

Wire  conductor: crimping

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Traditional Manufacturing Processes



Sheet metal processing

Powder- and Ceramics Processing

Plastics processing



Surface treatment

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Surface treatment, Coating, Painting

Post-production processes

Only affect the surface, not the bulk of the material

  • Improving the hardness

  • Improving the wear resistance

  • Controlling friction, Reduction of adhesion, improving the lubrication, etc.

  • Improving corrosion resistance

  • Improving aesthetics

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Mechanical hardening

Shot peening

Shot peening precision auto gears


Laser peening


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Vapor deposition

Deposition of thin film (1~10 mm) of metal

Sputtering: important process in IC Chip manufacture

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Thermal spraying

High velocity oxy-fuel spraying

Tungsten Carbide / Cobalt Chromium Coating

on roll for Paper Manufacturing Industry

Thermal metal powder spray

Plasma spray


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Deposit metal on cathode, sacrifice from anode

chrome-plated auto parts



Metal part on anode: oxide+coloring-dye deposited using electrolytic process

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Type of paints:

Enamel: oil-based; smooth, glossy surface

Lacquers: resin based; dry as solvent evaporates out; e.g. wood varnish

Water-based paints: e.g. wall paints, home-interior paints

Painting methods

Dip coating: part is dipped into a container of paint, and pulled out.

Spray coating:  most common industrial painting method

Electrostatic spraying: charged paint particles sprayed to part using voltage

Silk-screening: very important method in IC electronics mfg

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Electrostatic Spray Painting

Spray Painting in BMW plant

Silk screening

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These notes covered processes: cutting, joining and surface treatment

We studied one method of modeling a process, in order to optimize it

We introduced the importance and difficulties of process planning.

Further reading: Chapters 24, 21, 30-32: Kalpajian & Schmid