Peiman Mosaddegh – Manufacturing Process

Department of Mechanical Engineering

Peiman Mosaddegh – Manufacturing Process

Department of Mechanical Engineering

فورج

Peiman Mosaddegh, Ph.D.

Department of Mechanical Engineering Isfahan University of Technology

Spring 2017

Peiman Mosaddegh – Manufacturing Process

Department of Mechanical Engineering

PROCESSES

Mental Map

Material

Removal

Material

Transformation

Material

Addition

Bulk

Deform.

Casting

Processes

Polymer

Processes

Adhesion Joining Rapid Prototyping

Machining

Processes

Integration Interpretation Quality

•QFD •GD & T •Metrology

•SPC

•Push / Pull

•Lean Mfg.

•Turning

•Milling

•Drilling

•Grinding

•Sand

casting

•Diecast

•Investment

•other

•Forging

•Rolling

•Extrusion

•Drawing

Sheet

Metal

•Bending

•Stamping

•Blanking

•Punching

•Extrusion

•Inj. Molding

•Blow molding

•Rotomold,etc.

•Composites

•Welding

•Brazing

•SLA

•SLS

•3D

Printing

•other

DESIGN INDUSTRIAL

Time

Design for X Process Planning

MANUFACTURING

2

Peiman Mosaddegh – Manufacturing Process

Department of Mechanical Engineering

Basic Bulk Deformation Processes

Rolling

Extrusion

Forging

Drawing

Insert Fig similar

to Fig 20.1

Peiman Mosaddegh – Manufacturing Process

Department of Mechanical Engineering

Introduction

Deformation of metal using impact (hammer) or gradual

pressure (press) to form part of desired shape.

• Metal worked at ambient or elevated temperature

• Three types of die configurations

- Open die (Upset)

- Closed die (Impression Die)

- Flashless

Peiman Mosaddegh – Manufacturing Process

Department of Mechanical Engineering

Benefits

• “Near Net Shape” parts produced

• Little material wasted

• Stronger Parts - can achieve preferred grain orientation

• Parts can be produced at higher rate

Peiman Mosaddegh – Manufacturing Process

Department of Mechanical Engineering

Types of Products

• Gears

• Turbines

• Crankshafts

• Aircraft Structural Components

Peiman Mosaddegh – Manufacturing Process

Department of Mechanical Engineering

Upset (Open Die) Forging

• Metal flows without

constraint between two

dies

• Friction plays an

important role

• Forging may be done

incrementally (in steps)

• Dies typically flat

Peiman Mosaddegh – Manufacturing Process

Department of Mechanical Engineering

Upset (Open Die) Forging

• Produces simple shapes

• Often processed later by

other methods

Peiman Mosaddegh – Manufacturing Process

Department of Mechanical Engineering

Forging Calculations

ho ro

Top Platen

Bottom Platen

Work

%100x 0

10

h

hh F

Cylindrical Workpiece

Note: Yf = Ken

Reduction =

Engineering Strain…

True Strain…

0

101

h

hhe

1

01 ln

h

he

Strain Rate…

1

1

v

h

e

Peiman Mosaddegh – Manufacturing Process

Department of Mechanical Engineering

Forging Calculations

Ho ro

Top Platen

Bottom Platen

Work 1fF Y A

Compression Force:

F

Cylindrical Workpiece Frictionless, Uniform Deformation

Volume is conserved…

1100 hAhAV

Ideal (no friction, perfect plasticity)

0=initial state, 1=final state

Force in compression can be

calculated:

Y= material yield stress

Peiman Mosaddegh – Manufacturing Process

Department of Mechanical Engineering

An Example

Forging Calculations

Ho ro

Top Platen

Bottom Platen

Work

with K = 60 MPa & n = 0.12

Ho = 40 mm

F

Hf = 30 mm (final height)

Given:

Do = 50 mm

Yf

n Keuse

Frictionless, Uniform Deformation

Peiman Mosaddegh – Manufacturing Process

Department of Mechanical Engineering

An Example

Forging Calculations

Ho ro

Top Platen

Bottom Platen

Work

F K Y Af f

Ho = 40 mm

F

Hf = 30 mm (final height)

Given:

Do = 50 mm

with Kf = 1 + mD

3H

Assume m = 0.1

Accounting for Friction

Peiman Mosaddegh – Manufacturing Process

Department of Mechanical Engineering

Forging Calculations

Ho ro

Top Platen

Bottom Platen

Work

- Maximum force always occurs

at the end of forging

F

Note:

- Effect of friction is to increase

the required force

Peiman Mosaddegh – Manufacturing Process

Department of Mechanical Engineering

Slab Method Analysis

Forging Calculations

Assumptions:

Incompressible solid ( = 0.5)

Plain Strain (ez = 0)

Slab Width = unity

h dx

Top Platen

Bottom Platen

F

x

y

a

Rectangular cross-section

Peiman Mosaddegh – Manufacturing Process

Department of Mechanical Engineering

Rectangular Slab

Forging Calculations

Elemental Strip

h x

y

m y

x dx

m y

y

F 0x

F 0y

Peiman Mosaddegh – Manufacturing Process

Department of Mechanical Engineering

Rectangular Slab

Forging Calculations

Von Mises Yield Criteria (Distortion Energy Criterion):

h x

y

m y

x dx

m y

y

Y 1

2 1 2

2

2 3

2

3 1

2[( ) ( ) ( ) ]

Assumption: Yield in tension and yield in compression occur at same stress

Peiman Mosaddegh – Manufacturing Process

Department of Mechanical Engineering

Rectangular Slab

Forging Calculations

With boundary condition

h

x

Y Ce

m

2

General Solution:

h dx

Top Platen

Bottom Platen

F

x

y

a

x = 0 at x = a

And therefore y= Y’

Peiman Mosaddegh – Manufacturing Process

Department of Mechanical Engineering

Rectangular Slab

Forging Calculations

h

xa

Y eYP

)(2

'

m

1'

)(2

h

xa

X eY

m

Final Solution:

h dx

Top Platen

Bottom Platen

F

x

y

a

Peiman Mosaddegh – Manufacturing Process

Department of Mechanical Engineering

pressure highest at center

a

Rectangular Slab

Forging Calculations

3

2

)(2

h

xa

y

YeP

m

Final Solution:

nKY e

F

3

2Y

“Friction Hill”

Note that…

(For strain hardening material)

3

2

2

h

a

Ye

m

3

2Y

pressure highest at center=friction hill

Peiman Mosaddegh – Manufacturing Process

Department of Mechanical Engineering

a

Rectangular Slab

Forging Calculations

h

aYPavg

m1

3

2

Average Pressure: F

3

2Y

“Friction Hill”

3

2

2

h

a

Ye

m

3

2Y

Forging Force:

))(2)(( widthaPF avg

Peiman Mosaddegh – Manufacturing Process

Department of Mechanical Engineering

a

Similarly for a Cylinder…

Forging Calculations

h

rYPavg

3

21

m

h

xr

YeP

)(2m

Pressure: F

Y

“Friction Hill”

h

r

Ye

m2

Average Pressure:

Y

Peiman Mosaddegh – Manufacturing Process

Department of Mechanical Engineering

Barreling During Open Die Forging

Workpiece constrained

by friction - can’t

expand

Glass frit used to reduce

friction

Frictionless contact -

workpiece free to

expand

Peiman Mosaddegh – Manufacturing Process

Department of Mechanical Engineering

Grain Orientation & Barreling

cooled at base - less deformation

grain flow lines

Kalpakjian, S., Manufacturing Processes for Engineering Materials, 1997, p. 298

Peiman Mosaddegh – Manufacturing Process

Department of Mechanical Engineering

Dead Zones

Areas of no material

deformation

Peiman Mosaddegh – Manufacturing Process

Department of Mechanical Engineering

Upset (Open Die) Forging

Main Types of Forging

Peiman Mosaddegh – Manufacturing Process

Department of Mechanical Engineering

Closed Die - Impression Die Forging

• Dies with inverse shape

of part used

Main Types of Forging

AYKF fp

• Draft angle needed in order

to get part out of mold

• Flash created helps control

“back-pressure” in cavity

• More complex shapes

obtained

Peiman Mosaddegh – Manufacturing Process

Department of Mechanical Engineering

Closed Die - Impression Die Forging • Multiple forging steps or multiple hammer blows

often employed

Main Types of Forging

Kalpakjian, S., Manufacturing Processes for Engineering Materials, 1997, p. 320

Peiman Mosaddegh – Manufacturing Process

Department of Mechanical Engineering

Closed Die - Impression Die Forging

Die for Aircraft Landing Gear

Main Types of Forging

Ostwald, P., Manufacturing Processes & Systems, 1997, p. 331

Peiman Mosaddegh – Manufacturing Process

Department of Mechanical Engineering

Closed Die - Impression Die Forging

Forged Part Terminology

Main Types of Forging

Kalpakjian, S., Manufacturing Processes for Engineering Materials, 1997, p. 320

Peiman Mosaddegh – Manufacturing Process

Department of Mechanical Engineering

Closed Die - Flashless Forging

• Work completely

constrained within die

Main Types of Forging

• Volume of metal must be

controlled closely

• No flash produced

• Best for simple,

symmetric geometries

Peiman Mosaddegh – Manufacturing Process

Department of Mechanical Engineering

Closed Die - Flashless Forging

• Work completely

constrained within die

Main Types of Forging

• Volume of metal must be

controlled closely

• No flash produced

• Best for simple,

symmetric geometries

Peiman Mosaddegh – Manufacturing Process

Department of Mechanical Engineering

Material selection is also important

Forging

Metal or AlloyApproximate Forging

Temperature Range (C)

Aluminum Alloys 400 - 550

Magnesium Alloys 250 - 350

Copper Alloys 600 - 900

Carbon & Low-Alloy Steels 850 - 1150

Martensitic Stainless Steels 1100 - 1250

Austenitic Stainless Steels 1100 - 1250

Titanium Alloys 700 - 950

Iron-base Superalloys 1050 - 1180

Cobalt-base Superalloys 1180 - 1250

Tantalum Alloys 1050 - 1350

Molybdenum Alloys 1150 - 1350

Nickel-base Superalloys 1050 - 1200

Tungsten Alloys 1200 - 1300

Peiman Mosaddegh – Manufacturing Process

Department of Mechanical Engineering

Inspection of Forgings

Inspection Methods

- X-ray

- Ultrasonic

- Must be concerned with defect size and quantity

Can NOT make defect-free forgings…

Peiman Mosaddegh – Manufacturing Process

Department of Mechanical Engineering

Peiman Mosaddegh – Manufacturing Process

Department of Mechanical Engineering

Questions?????