project on:-design and analysis of punch tool used in

press shop

By :-

Parag Kapile

Dinesh Panda

Ritesh Kumar

Kaustubh Patil

Guided by:-

Mr.Rajkumar Shinde

Sponsored by:-

SIDDHESHWR INDUSTRIES Pvt. Ltd.

Siddheshwar industries is one of the fastest growing companies in the field of precision componentfor the Automotive and Engineering industries and are also suppliers to some of india’s largestengineering companies .

Siddheshwar ind. Manufacturing capabilites include extensive Forging & Machining processes withengineering resources for deveolping customer projects from prototype to production .

Siddheshwar industries are leading manufacturers of Gears , Crankshafts , Flanges , Albero shaftsfor automotive & non-automotive industry.

The client list includes one of india’s giants in the two & three wheeler field – BAJAJ AUTO ltd.

It was established in 1994.The buisness has grown from a small machine shop to a multiscalecompany with a turnover of Rs 170 Crore.

Mr.V.B.Takawane(CEO)

Mr.Raviraj

Takawane(director)

Mr.N.M.Chandekar (G.M.)

Mr.V.K.S.Nair(G.M. purchase)

Mr.S.Shaha(vice president)

Mr.N.Pathan(maintenance)

PROBLEM DEFINITION:--

The cost of tooling in sheet metal industries contributes a considerable part to the overall costof manufacturing a component. It is therefore imperative to keep down this cost by ensuringthat the tool works for a long period in production without interruption. One way ofachieving this objective is to reduce the stress on the tool during punching/blanking.

To reduce the required shearing force and stresses on the punch.

To accommodate a Gear primary helical (GPH) plate on a smaller capacity punch press.

To distribute the cutting action over a period of time.

A 15 TON press machine operation is done on a 5 TON press machine.

To find best suitable punch among different cutting profiles

of punches using Finite Element method.

To increase life of punching tool.View of a distorted punch

OVERVIEW OF PROJECT:-

Tool design and analysis

Present scenario (flat faced tool)

Design and calculation of stresses using

normal procedure

Proposal (tool with rilef shear

angle)

Calculation of stresses using Finite element

method

Snap through forces:-

Waveform signature in tool before adding shear

Waveform signature in tool after adding shear

Modelling of punch

To reduce the stress on the tool and thus enable thicker or moreresistant stock to be punched on the same press or to permit the use oflower-rated presses, the employment of a punch or die with groundrelief on its face is a common practice.

It is reported that punching/blanking forces vary with various amountsof shear relief on the tool face.

However, there is little information available to tool users as to howthe amount of shear relief has to be chosen in practice in relation to thepunching force required for a given product.

This project deals with the design analysis of various types of puncheswith special attention to their cutting profiles, using the finite-elementtechnique. Results obtained helps for the selection of punches forminimum distortion of the punch and reduced stress on the punch.

punch configuration of various shapes and slugs

D=12mm

D2=14mm

D3=16mm

Finite element procedure

Metallurgical properties of D2 tool steel:--

MATERIAL PROPERTIES VALUES

Ultimate compressive strength 2150 N/mm2

Young’s modulus 210* 103 N/mm2

Poisson ratio 0.3

Modulus of rigidity 80*103 N/mm2

Density 7860 kg/m3

Length of tool 61.34 mm

MATERIAL PROPERTIES VALUES

Ultimate shear strength of workpiece (tm) 639 N/mm2

Diameter of hole in workpiece 12 mm

Thickness of workpiece 6 mm

Percentage of penetration required 60%

Ultimate tensile strength of workpiece 520 N/mm2

Metallurgical properties of workpiece:--(GPH stainless steel)

Calculation of stresses:-

CASE I: Without shear (Flat face)

1.) Maximum puching load : (initial)

Pi = L * t * tm

Pi = p * 12 * 6 * 639

Pi = 144.538 * 103 N

Pi = 144.538 kN

2.) Total work done in punching :

W = 144.538 * 6 * 0.6

W = 520.336 kJ

CASE II : With Shear angle assume Ø =22.5o

Total work done = Pf ( 0.6 * 6 + 12 )

520.366 = Pf ( 0.6 * 6 + 12 )

Pf = 33.354 KN cutting complete at 60% penetration = 0.6

(assuming for stainless steel material)

D=12mm

Stresses:

1.)For Flat surface:-

σf =

σf = 1277.99 N/mm2

2.) For one way shear:-

σo =

σo = 294.91 N/mm2

Calculation of forces for fem modelI] load Acting on punch:

where,

a) calculation of force components for different nodal points

m

..….(coefficient of friction m =0.10)

b) In case of punch 2 & 3:

c)whilst in case of punch 4:

Nodal loads on the cutting edge surface:

Here the cutting edge nodal points includes 1, 10, 26.

Fx, Fy, & Fz are the components of Fp at 1, 10 & 26.Punch Profile No. Shear angle ∅ (degree) Node No. Force (N)

Fx Fy Fz

1 0 1

10

26

248

1003

3266

-248

-1003

-3266

2482

10027

32656

2 and 3 22.5 1

10

26

948

3837

12497

-948

-3837

-12497

2293

9264

30170

4 22.5 1

10

26

12497

3837

948

-1250

-384

-95

30170

9264

2293

cutting edge nodal points 1, 10 & 26:

1, 10, 26

Radial Deformation Vs Shear Angle

-500

-400

-300

-200

-100

0

100

200

0 6.5 7.5 15 22.5 30 37.5 45

R

a

d

i

a

l

d

e

f

o

r

m

a

t

i

o

n

∆

R

shear angle ∅(degree)

Radial deformation vs shear angle

concave shear

convex shear2

one way shear

puch load vs shear angle

0

10

20

30

40

50

60

70

80

90

100

0 7.5 15 22.5 30 37.5 45

F

o

r

c

e

(

k

N)

Shear angle degree ∅

puch load vs shear angle

Fx and Fy

Fz

Radial stiffness Vs Punch type

0

5

10

15

20

25

30

35

40

45

50

flat face convex shear concave shear one way shear

R

a

d

i

a

l

s

t

i

f

f

n

e

s

s

punch type

Radial stiffness(*1000 kN/mm) vs punch type

Radial stiffness

Axial stiffness vs punch type

0

50

100

150

200

250

300

flat face convex concave one way shear

A

X

I

A

L

S

T

I

F

F

N

E

S

S

Axial stiffness(kN/mm) vs Punch type

axial stiffness

principal stress vs punch type

0

200

400

600

800

1000

1200

1400

1600

flat face convex concave one way shear

P

R

I

N

C

I

P

A

L

S

T

R

E

S

S

principal stress(N/mm2) vs punch type

principal stress

Steps in ansys:

Step 1. 3-d modelling Step 2. Importing in ansys

Step 3. Applying loads and boundary

condition

Step 4.Meshing the model

Results from ANSYS

Result of Flat face

Results for shear tools

Result of Convex shear

Result of Concave shear Result of One side shear

Comparison of results:

Stress Calculated Results

(N/mm2)

Ansys Results

(axis symmetric loading)

(N/mm2)

Von mises Stress

(Maximum) Flat Face1277.99 1465.6

Von mises Stress

(Maximum) One Way Shear 294.91 312.49

Conclusions The present study on punch design has resulted in the development of 3-D finite-element

models of various types of punches and demonstrates the usefulness of these models in

solving practical problems involving a range of design parameters.

That the radial deformations of punches with balanced convex and concave shear have a

minimum value within the shear angle range of 17°-25° suggests that a shear angle of 22.5°

can be proposed safely for practical purposes.

That amongst the rigidity characteristics evaluated for all types of punches, the punch with

balanced convex shear, punch 2 & 3, shows the best performance suggests that this type of

punch can reasonably be recommended in practice in order to reduce the stress on the tool

and thus to enable thicker or more resistant stock to be punched on the same press or to

permit the use of a lower-rated press but punch 2 does not give good surface finish as

compared to punch 3.

Since the inclusion of eccentricity due to asymmetric load on the press is an important

factor in the punching/blanking process, the choice of punch 2, with balanced convex shear,

compared with sintered hard coating around circumferential edge of flat tool.

Important suggestions:

REFERENCES:-

Tools and Manufacturing Engineers Handbook, 3rd edn., McGraw-Hill, New

York, 1976.

Cyaril Donaldson , tool design, Tool Manuf. Eng.,

Fundamentals of tool manufacturing and die design by N.P.Mathur.

U.P. Singh, P,C. Veenstra and J.A. Ramaekers, Design study of the geometry of

a punching/ blanking tool, Ann. CIRP, (1977).

AISI D2 Tool steel facts by UDDHEOLM

Mini Review on Designing of Press Tools for Sheet Metal Parts in Journal of

Environmental Science, Computer Science and Engineering & Technology by

Kailash Kumar Lahadotiya, Abhay Dinkar Kakirde, and Asutosh Kumar Pandey