Application of ultrasonic excitation to metal forming

processes

M. Rosochowska• Manufacturing Engineering Research Group

Overview

• Objective

• Results

• Approaches

• Findings

• Future work

Objective

• Define the constraints to the application of ultrasonic to metal deformation

Approaches• Definition of processes:

• Experimental Analysis

• Finite Element Analysis

• Process simulation• Equipment design - FE methodology

• Parameters:

• Indentation

• Heading

• Wire flattening

• Back extrusion

• Amplitude of vibrations

• Deformation velocity

• Materials

Indentation Heading

Wire flattening Back extrusion

The Tool

FE results

Punch holder suspension

Vibration mode, Frequency 20kHz

FE analysis of threaded joint between

punch and tool holder

a) excitation a) tightening

Stresses induced by:

FE resultsSimulation of wire-flattening

Stress distributionTool load

V=150mm/s

Experimental resultsIndentation

Steel

0

0.01

0.02

0.03

0.04

200 400 600 800 1000

Punch pressure [MPa]

Sp

ec

ific

in

de

nta

tio

n d

ep

th

DI/

dp

A=0

A=0.01

Aluminium

0

0.2

0.4

0.6

0.8

1

1.2

1.4

0 200 400 600

Punch pressure [MPa]

Sp

ec

ific

in

de

nta

tio

n d

ep

th

DI/

dp

A=0

A=10

A=0

A=0.005

A=0.0065

Experimental results

Heading of Aluminium

hH

Do

D

0.00

0.10

0.20

0.30

0.40

0.50

3000 4000 5000 6000 7000 8000

Applied force [N]

Sp

eci

fic

he

ad h

eig

ht

(h/H

)

With Vibration

Without vibrations

Experimental resultsWire-flattening

Copper wire - 1.2 mm

h

do

Cu 0.58 0.42

Al 0.70 0.40

Al-G21 0.63 0.42

r =

0

50

100

150

200

250

300

0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 1.1

Die to Die Gap [mm]

Pu

ll-th

rou

gh

Fo

rce

[N

] Static

0.007/L

0.007/D

0.003/L

Experimental resultsBack extrusion

0

200

400

600

800

1000

1200

1400

0 0.5 1 1.5

Punch displacement [mm]

Me

an p

un

ch p

ress

ure

[M

Pa]

Steel

v=0.25mm/s, A=7.2m

1 - v=1mm/s, A=0 4 - 1mm/s, A=4.3m

2 - v=10mm/s, A=2.8m 5 - 0.5mm/s, A=4.6m

3 - v=5mm/s, A=2.8m 6 - 1mm/s, A=8.3m

Aluminium

0.00

100.00

200.00

300.00

400.00

500.00

600.00

0.00 0.50 1.00 1.50 2.00 2.50 3.00

Punch displacement [mm]

Pu

nch

pre

ssu

re [

MP

a] 2 3

1

5

4

6

Findings• Forging force - inversely proportional to excitation

amplitude and directly proportional to deformation velocity

• Excitation applicable to slow deformation-rate processes

• Industrially-significant forming force reduction in wire flattening and back extrusion

Findings

• High-strength work-materials require excessive amounts of energy to excite tools.

• Excitation applicable to processes in which deformation field in the work-material remains in steady-state

• Excitation amplitude limited by the permissible stresses and tolerable thermal changes in tools

Findings

• Application limited to small components

• The process is expensive because tool design is complex and energy consumption relatively large.

• Application limited to low-strength work-materials

Proposed future work

• Evaluate prospects of forming miniature components

• Evaluate prospects of using environmentally- friendly lubricants

• Evaluate machine design requirements for utilisation of tool excitation