Relationships Between Blanking Force and Part Geometry vs. Clearance, Tool Wear, and Sheet Thickness

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Relationships Between Blanking Force and PartGeometry vs. Clearance, Tool Wear, and SheetThicknessR. Hambli a , S. Kobi a , F. Guerin a & B. Dumon aa ISTIA–LASQUO , 62, Avenue Notre Dame du Lac, Angers, 49000, FrancePublished online: 16 Aug 2006.

To cite this article: R. Hambli , S. Kobi , F. Guerin & B. Dumon (2002) Relationships Between Blanking Force and PartGeometry vs. Clearance, Tool Wear, and Sheet Thickness, Quality Engineering, 15:2, 197-207, DOI: 10.1081/QEN-120015852

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Relationships Between Blanking Forceand Part Geometry vs. Clearance, ToolWear, and Sheet Thickness

R. Hambli,* S. Kobi, F. Guerin, and B. Dumon

ISTIA–LASQUO, 62, Avenue Notre Dame du Lac, Angers 49000, France

ABSTRACT

The blanking of metal parts for electronic components is subjected to a variety of

process parameters. In this paper, an experimental investigation into the blanking

process was carried out using tools with four different wear states and four different

clearances. The aim was to study the effects of the interaction between the

clearance, the wear state of the tool, and the sheet metal thickness on the evolution

of the blanking force and the geometry of the sheared profile.

Designed experiments are an efficient and cost-effective way to model and

analyze the relationships that describe process variations.

The results of the proposed experimental investigation show the strong

dependence between the geometrical quality of the blanked part and the magnitude

of the force applied on the tool as well as the variations in the process factors.

Key Words: Metal blanking process; Design of experiments; Response surface;

Tool wear; Clearance; Sheet thickness

INTRODUCTION

The increasing miniaturization of products of fine

mechanics in medical technology field, sensors,

actuators, integrated circuits, and electronic components

makes it necessary to manufacture parts with a high

quality level. The forming of such products requires

maximum accuracy and optimal manufacturing design.

Sheet metal cutting process of thin components using

both a punch and a die (Fig. 3), is one of the most

frequently used processes in industry.[1] Dependent on

the position of the sheared surface with respect to

197

DOI: 10.1081/QEN-120015852 0898-2112 (Print); 1532-4222 (Online)

Copyright q 2002 by Marcel Dekker, Inc. www.dekker.com

*Corresponding author. E-mail: [email protected]

QUALITY ENGINEERINGVol. 15, No. 2, pp. 197–207, 2002–03

©2002 Marcel Dekker, Inc. All rights reserved. This material may not be used or reproduced in any form without the express written permission of Marcel Dekker, Inc.

MARCEL DEKKER, INC. • 270 MADISON AVENUE • NEW YORK, NY 10016

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the workpiece coordinates, various shearing processes

are used such as blanking, piercing, and cutting.[1 – 3]

Unlike other operations, such as stamping and bending

where the aim is to plastically deform the sheet, these

operations lead to the total rupture of the metal.[4,5] As

the process is performed on material whose behavior is

nonlinear, it is submitted to complex strain and stress

states.[1,6] Before complete rupture, the material is

subjected to some phenomena of damage and crack

propagation caused by the punch penetration.

Various experimental studies carried out covering this

subject have shown that optimal choice of process

parameter is crucial in:

. avoiding, in certain cases, additional operations

such as removal of burrs to improve the geometri-

cal quality of the sheared edge,[5]

. increasing the fatigue life of the parts in service, as

shown by Lambert et al.,[7] and

. increasing the fatigue life of the tool.[8,9]

The blanking of thin metal parts is subjected to a

variety of process parameters. Material properties and

the process factors affect the quality of the blanked part.

The main objectives of the process design in metal

blanking is to choose the important process parameters in

an optimal way that ensures a high quality part.

Engineers are often required to examine the process

parameters in order to optimize production.

Review of the most recent studies in the field of

manufacturing processes[10,11] shows that, despite the

progress in blanking analysis, there is still a lack of models

allowing the optimal design of sheet metal shearing

processes. Currently, correct parameter choice for a new

product manufactured by sheet metal blanking is deter-

mined empirically by a large number of expensive tests.

The clearance, the wear state of tool, and the thickness

of the sheet are the major factors determining the shape

and the quality of the workpiece.[5,10,12] The blanking has

a large number of inputs. Each of these inputs has an

associated variation, which leads to the variation in the

final part.[5,13,14]

Due to the large number of controllable and

uncontrollable inputs, associated variations, and relation-

ship between stress and strain in metal forming, the

blanking system behaves in a manner similar to a

deterministic chaotic system. To understand this system

fully and control the output through the control of the

inputs is difficult if not intractable at present.

A more effective method of controlling the output is

to understand the input variation more thoroughly and

account for this in defining the operating point to ensure

robustness to this identified variation.

An operation window in sheet metal forming is an

area in the input space which corresponds to the produc-

tion of a good part. The size of the operating window

corresponds to the sensitivity of the part quality to

variation in the input parameters. With an understanding

of the process and associated variation the most robust

operating point within this window can be identified.

In production, this can be very difficult to identify

fully the variation in a part produced since a large

number of experiments need to be performed. This

increases both the costs and the associated lead times.

Therefore, there is a need to identify this operating

variation and an associated robust operating point in the

shortest period of time at a low cost.

DESIGN OF EXPERIMENTS

The accuracy of workpieces can be characterized by

the following errors: dimensional error, positional error,

and form error (Fig. 1).

The errors on blanks are influenced by material, the

tool shape, process variations, and the machine. The form

errors represented in Fig. 2 are connected to the geometry

of the sheared edge such as the rollover depth, the

fracture depth, the smooth-sheared depth, the burr forma-

tion, and the fracture angle.

Various experimental studies[5,6,8] showed that, for a

given material, the blanking force F and the depth

characteristics of the blanked profile (Fig. 2) are affected

by the blanking clearance, the wear state of the tool, and

the thickness of the sheet.

Influence of Blanking Clearance

In blanking processes, the clearance (Fig. 3) expressed

in percent of the sheet thickness, is defined by:

c ¼ 100Dd 2 Dp

tð%Þ ð1Þ

Figure 1. Factors affecting errors on blanked workpieces.

Hambli et al.198



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where Dd, Dp, and t are the die diameter, the punch

diameter, and the sheet thickness, respectively.

It was established by various authors[3 – 5,12] that the

mechanical and geometrical aspects of the sheared edge

during the blanking operation depend mainly on the

clearance c between the punch and the die (Fig. 3). There-

fore, in order to study the influence of this design parame-

ter, four tools have been designed corresponding to four

different clearances, 5, 10, 15, and 20%. These values

correspond to the most used clearances in the industries.

Influence of the Tool Wear

The design of the tool is one of the main features in

the industrial process. Therefore, it is necessary to study

the effects of the tool wear on the blanking force and the

sheared profiles’ variations. The quality of the workpiece

is governed by the state of the worn tool.[5,8]

Wear is defined as a slow degradation of the blanking

tool caused by friction involved between the tool and

sheet metal. The rate of wear is affected by parameters

such as tool material, blanked part material, punch–die

clearance, punch velocity, lubrication, and material

thickness. Generally, wear takes place on the external

surface of the tool. It causes the cutting edges to be

rounded (Fig. 4). Therefore the influence of the tool wear

can be accounted for by changing the values of the edge

radii Rwp and Rwd (Fig. 4).

Experimental investigation into the blanking process

was carried out using punches with different wear states.

The aim was to define the relationship between part

geometry and the blanking force vs. the tool wear

evolution.

Four wear states of the tool were chosen correspond-

ing to:

. One new die with Rwd ¼ 0:01 mm:

. Four punches with different edge radii Rwp ¼

{0:01; 0:06; 0:12; 0:2} mm:

Influence of the Sheet Thickness

For a given material, the energy requirement in

blanking is influenced by the sheet thickness. It has been

observed that:

Figure 2. Geometry of the sheared workpiece.

Figure 3. Illustration of the punch and die clearance. Figure 4. Wear profile of the cutting edges of the tool.

Blanking Force and Part Geometry 199



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. The blanking energy decreases with increasing

clearance-to-sheet thickness ratio c/t and increases

with increasing sheet thickness.[1,5]

. The proportions of the different depth character-

istics of the sheared profile are affected by the

thickness.[3 – 5]

To study the effects of the interaction between

the clearance, the wear state of the tool, and the

sheet thickness, a series of experiments have been

carried out with two thickness values equal to 1.5 and

3 mm.

Design Factors

A full factorial experiment was designed for three

control variables: clearance (4 levels), wear state of the

punch (4 levels), and sheet thickness (2 levels). Table 1

produced 32 experiments to study the effect of each

variable and the interactions between them.

Table 1

Experimental Design

Variables

Experimental

Point

Clearance

(%)

Wear Radius (mm)

(Only for the Punch)

Thickness

(mm)

1 5 0.01 3

2 5 0.01 1.5

3 5 0.06 3

4 5 0.06 1.5

5 5 0.12 3

6 5 0.12 1.5

7 5 0.2 3

8 5 0.2 1.5

9 10 0.01 3

10 10 0.01 1.5

11 10 0.06 3

12 10 0.06 1.5

13 10 0.12 3

14 10 0.12 1.5

15 10 0.2 3

16 10 0.2 1.5

17 15 0.01 3

18 15 0.01 1.5

19 15 0.06 3

20 15 0.06 1.5

21 15 0.12 3

22 15 0.12 1.5

23 15 0.2 3

24 15 0.2 1.5

25 20 0.01 3

26 20 0.01 1.5

27 20 0.06 3

28 20 0.06 1.5

29 20 0.12 3

30 20 0.12 1.5

31 20 0.2 3

32 20 0.2 1.5

Hambli et al.200



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EXPERIMENTAL PROCEDURE

Experiments using devices equipped with force

transducers were performed by a 4000 kN hydraulic

press (Fig. 5). The process studied here consists of an

axisymmetric blanking operation of a metal sheet with

1.5 and 3 mm thickness. The geometrical data are shown

in Fig. 6. Carbon steel (0.6% C), was blanked using a

40 mm diameter die and a range of punch–die clearances

from 5 to 20%. Punches were of edge radii in the range

0.01–0.2 mm and one die with edge radius equal to

0.01 mm.

RESULTS

Table 2 contains results for the blanking force, the

fracture angle, and the fracture zone depth obtained for

the 32 experimental conditions. In this article, a design

of experiments is used for modeling and analyzing

the response of interest that is influenced by several

variables.

We need to address the following three distinct issues.

1. Optimizing these three responses or at least

finding the best compromise according to one’s

preferences.

2. Finding a clearance setting that is robust to wear

and to variations in sheet thickness, considering

that during production, wear and thickness are

difficult-to-control noise factors.

3. Identifying a model that is valid even when the

sheet thickness is modified, considering that sheet

thickness is a “block” factor.

The interactions between controllable factors (clear-

ance) and noise factors (wear and thickness) are useful to

reduce the influence of the noise factors and thereby to

“robustize” the process against variations in tool wear

and sheet thickness. However, if the objective is to find a

model that is valid even when the sheet thickness value is

changed, then it is preferable not to have interactions

between thickness and the other factors. It is often

assumed that block factors (such as thickness) do not

interact with the other factors; otherwise, the model is

modified according to the block factor setting. The

thickness main effect is not important in itself; what is

important is to identify the optimal clearance setting and

the tool wear states that are not too detrimental to the

process, whatever the sheet thickness.

Assuming that there is, most of all, a need for models

that are robust to differences in sheet thickness (sheet

thickness is considered to be a block factor) then, based

on the experimental results, three models may be

elaborated allowing for the analysis of the clearance

effect and the tool wear effect on fracture depth, fracture

angle, and maximum blanking force.

For each sheet metal thickness, the response surface F

describing effects of x1 and x2 can be expressed by:

y ¼ F ðx1; x2Þ þ 1 ð2Þ

where 1 represents experimental errors. F (x1, x2) re-

presents the hypothetical value of the response y that

would be obtained in the absence of experimental error.

x1 and x2 are the design variables that correspond to the

wear radius of the cutting edge of the tool and the

clearance.

Figure 7a and b are response-surface graphs showing

the effects of both tool wear and clearance on the

blanking force variation for two thicknesses, 3 and

1.5 mm. The figure clearly shows that for small clear-

ances less than 10%, the blanking force is quite high and

the minimal force value corresponds to a clearance of

10%. It can be shown that, starting from this optimal

value, increasing the clearance increases force variation.

Figure 6. Axisymmetric model of blanking operation.

Figure 5. Schematic illustration of the testing device.




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The relationship describing the blanking force

variation can be written in the following form:

F ¼ ð0:3c2 2 3:93cÞ þ ½22860ðRwpÞ3

þ 940ðRwpÞ2 2 14Rwp� þ 60t 1:27 ð3Þ

By comparing Fig. 7a and b, we can see the interaction

effects of decreasing the sheet thickness by 1/2. It is

important to note that the response surface has the same

shape and that the average force of blanking is reduced by

a factor of 2.4. It can be observed that the blanking force

increases with increasing wear as a result of increased

punch penetration until the final rupture of the sheet.

The relationship between the fracture angle and the

clearance, tool wear, and sheet thickness is shown in

Fig. 8. It may be noted that increase in clearance

increases significantly the fracture angle b as a conseque-

nce of the increasing of the punch penetration correspond-

ing to cracks formation into the sheet. Both responses

show that the tool wear radius has a little influence on the

variation of b. The comparison between the two curves

Table 2

Design Points Effects

Variables

Experimental

Point

Clearance

c (%)

Wear Radius of the

Punch Rwp (mm)

Thickness

t (mm)

Blanking Force

F (kN)

Fracture Angle

b (8)

Fracture Depth

Har (%)

1 5 0.01 3 234 3.898 73.5

2 5 0.01 1.5 98 3.94 72.7

3 5 0.06 3 235 4.12 69.5

4 5 0.06 1.5 98.5 4.421 64.8

5 5 0.12 3 240 4.421 64.8

6 5 0.12 1.5 100.5 5.180 55.3

7 5 0.2 3 245 4.899 58.5

8 5 0.2 1.5 102.5 6.715 42.7

9 10 0.01 3 231 7.737 74.1

10 10 0.01 1.5 97 7.761 73.8

11 10 0.06 3 233 7.858 72.9

12 10 0.06 1.5 97.5 8.009 71.5

13 10 0.12 3 235 8.009 71.5

14 10 0.12 1.5 98.5 8.328 68.8

15 10 0.2 3 240 8.219 69.7

16 10 0.2 1.5 100.5 8.796 65.1

17 15 0.01 3 233 11.576 74.2

18 15 0.01 1.5 97.5 11.583 74.2

19 15 0.06 3 235 11.609 74

20 15 0.06 1.5 98.5 11.648 73.8

21 15 0.12 3 240 11.648 73.8

22 15 0.12 1.5 100 11.726 73.3

23 15 0.2 3 245 11.7 73.5

24 15 0.2 1.5 102.5 11.833 72.6

25 20 0.01 3 235 15.416 74.3

26 20 0.01 1.5 98.5 15.405 74.4

27 20 0.06 3 235 15.362 74.6

28 20 0.06 1.5 98.5 15.297 74.9

29 20 0.12 3 242 15.297 74.9

30 20 0.12 1.5 101.5 15.170 75.5

31 20 0.2 3 247 15.212 75.3

32 20 0.2 1.5 103.5 15.003 76.4

Hambli et al.202



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shows that there is no influence of the sheet thickness on

the fracture angle evolution.

In this article, based on a theoretical investigation of

the blanking process developed in a previous work,[5] a

mathematical investigation on the fracture angle, makes

it possible to express b evolution as:

b ¼c

1 þRwp

t2 ad bd þ

Rwp

0:01tc

� � ð4Þ

where ad and bd are two material coefficients

characterizing the blanked material ductility. In the

case of a 0.6% carbon steel, these coefficients are: ad ¼

0:1686 and bd ¼ 1:5255:The 3D response surface graph of Fig. 9 presents the

interaction effects on the fracture zone depth variation.

The proportion of the fractured area increases with

increasing clearance and decreases with increasing wear.

The flatter response surface (Fig. 9a) means that fracture

depth is less sensitive to variation in tool wear and

clearance for a thicker sheet metal.

The mathematical relationship describing the fracture

zone depth response surface can be written in the

following form:

Har ¼ 1 þRwp

t2 ad bd þ

Rwp

0:01tc

� �ð5Þ

Analysis of Variance

When mixed-level designs (in which not all factors

have the same number of levels) are performed, the

analysis of variance (ANOVA) method cannot be used.

This is because the variance of the factor effect estimates

differs according to the number of levels; the smaller the

number of factor levels, the greater the accuracy of the

factor effect estimates. Using the ANOVA method to

discriminate between statistically significant effects and

effects that are not significant becomes quite complex.

Since the ANOVA method cannot be used, identifying

the “real” effects from those that are due only to

experimental errors may be somewhat subjective.

Factor Effects on the Blanking Force

The average blanking force when all the tests are

considered is 168.70 kN. Table 3 indicates the differ-

ences between the general mean and the mean at each

factor level. To minimize the blanking force, the cleara-

nce should be set at 10% so that the average blanking

force is decreased by 2.14 kN (see Table 3 and Fig. 7).

Sheet thickness and tool wear can be considered as noise

factors, since they are difficult to control during normal

production. Tools wear out and different types of sheets

need to be processed. It can be observed that the blanking

force increases with increasing wear as a result

of increased punch penetration until the final rupture of

the sheet. That increase is more noticeable for wear

radius values that are between 0.06 and 0.12 mm (see

Table 3). Suppose that the clearance is set at 10% to

minimize the amount of blanking force, as the tools wear

out the amount of force would need to be increased.

However, we also need to consider the interactions

between clearance and tool wear, since the clearance and

tool wear effects cannot be strictly added. When the

clearance is set at 10%, the tool wear effect is slightly

reduced—at lower wear radius values the amount of

blanking force is slightly greater than when the clearance

Figure 7. Blanking force evolution vs. clearance and wear tool variation.




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and tool wear effects are added to one another; whereas

at larger tool wear values, the amount of blanking force is

slightly lower than anticipated when the interaction

effects are not accounted for (see Table 4). In other

words, when the clearance is set at 10%, the process is

more robust to variations in the degree of tool wear. When

the thickness is increased from 1.5 to 3 mm, a much

greater amount of blanking force is required (þ69.1 kN).

Due to clearance by thickness interactions, the effect

of thickness is slightly smaller when the clearance is set

at 10% and due to tool wear by thickness interactions, the

influence of thickness is slightly reduced at lower values

of tool wear (see Table 5). A clearance of 10% does not

only allow for a minimization in the blanking force, it is

also more robust against both the amount of tool wear

and the amount of sheet thickness.

Factor Effects on the Fracture Angle

The clearance effect on the fracture angle evolution is

very significant and almost linear (see Table 6 and

Fig. 8). Increasing punch penetration causes crack

formations in the sheet. The fracture angle evolution is

also increased at higher levels of tool wear but that effect

is barely noticeable when compared to the clearance

effect. The fracture angle is slightly smaller when the

thickness increases, again this is a very minor effect

compared to the clearance effect.

To study the clearance by wear radius interaction,

no less than 16 levels (and nine degrees of freedom)

are required. Note that the degree of precision on the

factor effects decreases when the number of levels

increases. Because the interaction effects are so small

Figure 8. Fracture angle evolution vs. clearance and wear tool variation.

Figure 9. Fracture depth evolution vs. clearance and wear tool variation.

Hambli et al.204



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(see Tables 8 and 9) compared to the clearance effect

and their degree of precision is not high, it was decided

not to study these interactions.

Factor Effects on the Fracture Depth

The average fracture depth is 68.28% when all tests

are considered. The clearance effect on fracture depth is

nonlinear (see Table 10 and Fig. 9), the response reaches

a maximum when the clearance is set at 15%

(þ5.45% over the general mean). The wear radius also

has a strongly nonlinear effect; as it increases the

fracture depth decreases, that decrease is rather slow

between 0.01 and 0.12 mm wear radius values. However,

for a wear radius of 0.2 mm, the response drops

dramatically (210.34% below the general mean).

Interestingly when the clearance is set at 10 or 15%,

the wear radius effect is considerably reduced, whereas

for a 20% clearance, the wear radius effect is greatly

reinforced.

For thicker 3 mm sheets, the amount of fracture

depth is increased (þ3.57%). Due to thickness by

clearance and thickness by wear radius interactions, for

thicker 3 mm sheets, the clearance and wear radius

effects are reduced. However, for thinner 1.5 mm

sheets, the clearance and wear radius effects are

reinforced (Table 11).

CONCLUSION

The experimental investigation of the sheet metal

blanking process makes it possible to study the effects of

the interaction between the wear state of the tool, the

punch–die clearance value, and the thickness of the sheet

on the blanking force and the geometry of the sheared

edge.

Table 4

Clearance by Wear Radius Interaction

Interactions

Clearance

Level

Wear Radius

Level

Clear £

Wear

1 1 0.015625

2 20.109375

3 0.078125

4 0.015625

2 1 0.640625

2 1.015625

3 20.796875

4 20.859375

3 1 20.484375

2 0.140625

3 0.078125

4 0.265625

4 1 20.171875

2 21.046875

3 0.640625

4 0.578125

Table 5

Clearance by Thickness and Wear Radius by Thickness

Interactions

Clearance

Level

Thick £

Clear

Wear

Radius

Thick £

Wear

1 0.203125 1 21.359375

2 20.921875 2 20.984375

3 0.203125 3 0.453125

4 0.515625 4 1.890625

Table 6

Main Effects Fracture Angle Response

Factors

Levels Clearance Wear Radius Thickness

1 25.231875 20.297096429 0.1198125

2 21.8415 20.1828125 20.1198125

3 1.73425 0.089375

4 5.339125 0.348146341

Table 3

Main Effects Blanking Force Response

Factors

Levels Clearance Wear Radius Rwp Thickness

1 0.484375 23.569196429 269.109375

2 22.140625 23.0265625 69.109375

3 0.234375 2.1328125

4 1.421875 4.32507622




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The design of experiments method used for modeling

the response surfaces of interest makes it possible for a

better understanding of the blanking manufacturing

process. The behavior of each measured response is

described by a deterministic relationship between

the response and both factors, clearance and wear state

of the tool, for each sheet metal thickness. Therefore, it is

possible to determine the best conditions of the factors to

optimize a desired output.

The process signatures indicate that the maximum

shearing force, the fracture angle, and the fractured

surface depth are influenced by the material condition as

well as the geometric characteristics of the tools and their

configuration. The analysis of the tool wear influence

allows for the monitoring of the blanking operation and,

thus, the parts quality variations during the forming

process may be predicted.

This investigation shows that in order to minimize the

blanking force, the clearance should be set at 10%.

However, to minimize the fracture angle and the fracture

depth, it is preferable to set the clearance at 5%. When

clearance is set at a 10% value, the process is slightly

more robust to tool wear as far as the blanking force

response is considered and it is considerably more robust

(almost insensitive) to tool wear and sheet thickness as

Table 7


Interactions

Clearance

Level

Wear Radius

Level

Clear £

Wear

1 1 20.513625

2 20.288125

3 0.06

4 0.74175

2 1 20,074

2 20.0155

3 0.037625

4 0.051875

3 1 0.18075

2 0.10375

3 20.019625

4 20.264875

4 1 0.406875

2 0.199875

3 20.078

4 20.52875

Table 8


Interactions

Clearance

Level

Thick £

Clear

Wear

Radius

Thick £

Wear

1 20.2449375 1 0.1120625

2 20.0140625 2 0.0665625

3 0.0876875 3 20.0088125

4 0.1713125 4 20.1698125

Table 9

Main Effects Fracture Depth Response

Factors

Levels Clearance Wear Radius Rwp Thickness

1 25.559375 6.299196429 23.578125

2 2.640625 4.8790625 3.578125

3 5.453125 3.175520833

4 22.534375 210.34153963

Table 10


Interactions

Clearance

Level

Wear Radius

Level

Clear £

Wear

1 1 4.721875

2 0.671875

3 24.140625

4 21.253125

2 1 22.628125

2 22.478125

3 22.240625

4 7.346875

3 1 25.190625

2 23.590625

3 21.803125

4 10.584375

4 1 3.096875

2 5.396875

3 8.184375

4 216.678125

Hambli et al.206



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far as the fracture depth response is considered. Whether

clearance should be set at 5 or 10% ultimately depends

on the priorities of the practitioners.

As a conclusion drawn from the proposed investi-

gation, it is possible to optimize sheet metal blanking

process by a proper selection of the clearance.

ABOUT THE AUTHORS

R. Hambli is an associate professor at the University

of Angers (ISTIA). He has been involved in several

research and development projects in optimization of

metal-forming processes areas, Reliability-Based finite

element analysis, and damage mechanics. He is an active

reviewer for three international journals.

S. Kobi is an associate professor at the University of

Angers (ISTIA). His fields of interest include process

diagnosis, statistical process control (SPC), and design of

experiments (DOE).

F. Guerin is an associate professor at the University of

Angers (ISTIA). He has completed extensive research in

reliability in mechanics and accelerated testing areas.

B. Dumon is a professor at the University of Angers

(ISTIA). He is the Head of LASQUO Laboratory. He is

also a member of IEEE and ASQ American societies. He

is currently manager of projects in the areas of reliability

and Bayesian methods.

REFERENCES

1. Lange, K. Handbook of Metal Forming; McGraw-Hill

Book Company: New York, 1985.

2. Osaki, T.; Yamasaki, S.S. Effect of the Geometry of

Cutting Edge of Tool in Blanking Process and Punching.

Mem. Fac. Eng., Kyushu Univ. 1984, 38 (4), 371–395.

3. Kalpakjian, S. Manufacturing Processes for Engineering

Materials, 2nd Ed.; Addison Wesley Publishing Com-

pany: Reading, MA, 1991.

4. Chang, T.M. Shearing of Metal Blank. J. Inst. Met. 1951,

78, 393–414.

5. Hambli, R. Etude Experimentale, Numerique et Theori-

que du Decoupage des Toles en Vue de l’Optimisation du

Procede. These de Doctorat, ENSAM d’Angers, 1996.

6. Maillard, A. Etude Experimentale et Theorique du

Decoupage. These de Doctorat, Universite Technologique

de Compiegne, 1996.

7. Lambert, Y.; Bignonnet, A.; Roesch, L. Prevision, du

Comportement en Fatigue de Structures Minces en Aciers

a Haute Resistance Dual-Phase et Microallies. Mem.

Etudes Sci. Rev. Metall. 1991, 12, 209–225.

8. Grosset, E.; Maillard, A.; Turbat, A. Usure en Decoupage,

CETIM 1987, Rapport No. 101580.

9. Grosset, E.; Peyre, P.; Cherry, P.; Gasnier, J.; Tournier,

C. Les depots PVD et CVD en Poinconnage et Relevage

de Collerette, CETIM 1989, Informations No. 111,

55–61.

10. Proceedings of the 7th International Conference on Sheet

Metal (SheMet’99), Erlangen, Germany, Sept 25–28,

1999.

11. Proceedings of the 8th International Conference on Sheet

Metal (SheMet’2000), Birmingham, UK, April 17–18,

2000.

12. Jana, S.; Ong, N.S. Effect of Punch Clearance in the High-

Speed Blanking of the Thick Metal Using an Accelerator

for Mechanical Press. J. Mech. Working Technol. 1989,

19, 55–72.

13. Kasuga, Y.; Tsu Tsumi, S.; Mori, T. Investigation into

Shearing Process of Ductile Sheet Metals. Mem. Fac.

Eng. Nagoya Univ., Jpn 1979, 1–46.

14. Osaki, T.; Yoshikai, T. Effect of Profile in Basal Section

in Shearing Proces. Mem. Fac. Eng., Kyushu Univ. 1978,

38 (3), 249–273.

Table 11


Interactions

Clearance

Level

Thick £

Clear

Wear

Radius

Thick £

Wear

1 0.271875 1 23.465625

2 22.453125 2 22.790625

3 23.790625 3 22.053125

4 5.971875 4 8.309375




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Documents

Relationships Between Blanking Force and Part Geometry vs. Clearance, Tool Wear, and Sheet Thickness