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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

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Traditional Manufacturing Processes



Sheet metal processing

Powder- and Ceramics Processing

Plastics processing



Surface treatment


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


A process to cut components, stock, etc.

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



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

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


Precise process for mass-production of complex geometry parts

(complicated hole-shapes)

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

Drilling, Reaming, Boring

Processes to make holes

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

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


Processes to make threads in holes

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

Automated tapping

Manual tap and die set

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

Abrasive tools and Machines


Processes to cut cylindrical stock into revolved shapes

Process character: high MRR, high surface, dimension control

Turning operations

Fixturing parts for turning









Versatile process to cut arbitrary 3D shapes

Process character: high MRR, high surface, dimension control

Common vertical milling cutters




Up and Down milling

Fixtures for Milling: Vise

Fixtures for Milling: Clamps

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]

Geometry of the cutting tool

Modeling: Mechanism of cutting

Old model: crack propagation

Current model: shear

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.

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).

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.

Process modeling: empirical results

Experimental chart showing relation of tool wear with f and V

[source: Boothroyd]

Modeling: surface finish

Relation of feed and surface finish

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

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

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

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

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]

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

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:

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 modelVtn = C’  t = C’ 1/n / V1/n = C/V1/n

Process parameters optimization: Speed

Average cost per item:

Process parameters optimization: Speed

Optimum speed (to minimize costs)

Optimum speed (to minimize time)

Average time to produce part:

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*

Process Planning

The process plan specifies:


tools, path plan and operation conditions



possible machine routings


Process Planning

Operation sequencing examples (Milling)

big-hole step  small hole


small holestep  big-hole


step  hole


hole  step

Traditional Manufacturing Processes



Sheet metal processing

Powder- and Ceramics Processing

Plastics processing



Surface treatment

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

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.

Flame: 3000C

Fusion welding

Oxy-acetylene welding

Arc welding



arc: 30,000C

Gas shielded arc welding





Ti, Mg,

Thin sections

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

Solid state welding

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

Cold welding (roll bonding)

coins, bimetal strips

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

Resistance welding

Welding metal strips: clamp together, heat by current

Spot welding

Seam welding


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


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

Traditional Manufacturing Processes



Sheet metal processing

Powder- and Ceramics Processing

Plastics processing



Surface treatment

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

Mechanical hardening

Shot peening

Shot peening precision auto gears


Laser peening


Case hardening

Vapor deposition

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

Sputtering: important process in IC Chip manufacture

Thermal spraying

High velocity oxy-fuel spraying

Tungsten Carbide / Cobalt Chromium Coating

on roll for Paper Manufacturing Industry

Thermal metal powder spray

Plasma spray



Deposit metal on cathode, sacrifice from anode

chrome-plated auto parts



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


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


Electrostatic Spray Painting

Spray Painting in BMW plant

Silk screening


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

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