Simulation Driven Innovation 1

Formability and Tonnage Calculation Using HyperForm.

Prakash J. Banait Head Application

NRB Bearings Ltd.

2nd Pokhran Rd.,Thane 400 610

Sohail Shaikh Sr. Engineer

NRB Bearings Ltd.

2nd Pokhran Rd.,Thane 400 610 St.salunke@nrbbearings.co.in

Suresh T. Salunke Head Engineering

NRB Bearings Ltd.

2nd Pokhran Rd.,Thane 400 610

Abstract:

The process of new product development through sheet metal forming is one of the most common manufacturing processes existing in industries;

however it is not easy to design the process and the tools for most of the components. Material breakage, wrinkling, shape defects, cracks are the

defects encountered in sheet metal forming operation. Such defects can be foreseen during die development using HyperForm and Radioss

forming simulation technique, and through simple design change their occurrence can be prevented during manufacturing.

The paper converses the integration of sheet forming simulation in the tool surface development and process development phase. It discusses

about the different results obtained from the simulation which help to derive the solution if the component fails during forming. Virtual tryouts

results in reduction of time and cost. It is helpful in deciding the tonnage, geometry and the material properties of the product to design the

manufacturing process effectively.

Introduction:

Sheet metal forming involves complicated deformation process with material, geometrical and contact non linearity.

For obtaining the optimized design of such forming processes investigations into the details of deformation,

formation of wrinkles stretching and cracks are extremely important.

In industry many physical try outs are carried out by making prototypes using thumb rules and empirical formulae to

find right manufacturing parameters by trial and error. Based on the results obtained from the tryouts, the parameters

are altered until the best result is obtained. This approach is time consuming and expensive and calls for metal

forming simulation.

The primary objective of the sheet metal forming simulation:

1) Predict the metal flow

2) Check the feasibility of producing parts without flaws

3) Optimize and freeze the tool design

4) Optimize the process parameters.

The glory of forming simulation is that it does so in the virtual world before the tool is actually built. Solutions to

the various problems are diagnosed prior to manufacturing and can be rectified in short time. Forming simulation

often called as virtual manufacturing can be used to see all the desired outputs from a forming operation such as

thinning, wrinkles, stretching, cracks, etc.

Simulation Driven Innovation 2

Process methodology:

Blank

Component

The sleeve shown in the above figure is manufactured by a series of the forming and the cutting

process.

Process flow for Sleeve manufacturing:

Material Properties:

Raw material: DD quality low carbon steel

Sheet Thickness: 1.63mm

Yield Stress: 350 Mpa

Strength Coefficient: 700Mpa

Youngs Modulus: 205000Mpa

Poissons ratio: 0.27

Blank First Cupping Second Cupping Third Cupping

Calibration Bottom Cutting Collar Cutting Final

Component

Simulation Driven Innovation 3

First Cupping:

The assembly set up for the first cupping is shown in the figure below. The blank is given the specified material

properties, the components are meshed considering the sheet metal geometry, displacement and curvature. Areas of

metal flow and curvature are meshed critically.

First Cupping Assembly

Punch

Die

Blank

Blank Support

Simulation Driven Innovation 4

Formability diagram shows the areas of the compression and the risk of cracks and wrinkles generated during the first cupping.

The maximum tonnage reported for first cupping in HyperForm for first cupping is 25485N.

Simulation Driven Innovation 5

Second Cupping:

The assembly set up for second cupping:

Second Cupping Assembly

Blank after First

Cupping

DIE

Punch

Simulation Driven Innovation 6

Formability limit diagram for second cupping.

The maximum tonnage reported for first cupping in HyperForm for second cupping is 66657N

Third Cupping:

Blank after

Second Cupping

DIE

Punch

Simulation Driven Innovation 7

Third Cupping Assembly

Formability limit diagram for third cupping

The maximum tonnage reported for first cupping in HyperForm for third cupping is 29662.3N

Simulation Driven Innovation 8

Calibration:

Formability limit diagram for Calibration

Blank after Third

Cupping

DIE

Punch

Simulation Driven Innovation 9

The maximum tonnage reported for first cupping in HyperForm for calibration as shown in the simulation will be

591834.5N

Bottom and Collar Cutting:

Simulation Driven Innovation 10

Bottom Cut part Collar Cut part(Final Component)

Benefits Summary

Following benefits are expected to be derived by using HyperForm Press tonnage requirement at each stage can be calculated to a degree of accuracy. This data can

be utilized in deciding number forming stations a press can take.

The raw material size for the product can be calculated to a good degree of accuracy. This will help to reduce the scrap generated and result in better profitability of the organization.

This analysis reveals very important aspect of selection of process parameters viz. coefficient of friction between various contacting surfaces. Different coefficient of friction has different

formability results. This analysis also reveals the effect of different binder force values on the

forming process and provides guidelines for binder forces to be applied in the practical forming.

The tryout time can reduce drastically

The result of forming simulation can be incorporated while doing other analysis to optimize the material thickness and grade.

Challenges:

The co relation between the inputs like friction, material properties and the actual try out condition is

difficult. Actual testing of material is required whenever new grade is to be tried out.

Optimization of the solving time and accuracy level to be established and used

Improvement in the software to automate the set up when the geometry changes required are frequent.

Conclusion:

In todays scenario of latest new product development trends, where the time to introduce a new product is under

pressure, forming simulation for each sheet metal component has become essential. Sheet metal simulation help the

tool designer to understand metal flow in a better way for complex shapes, which in turn increases the component

quality and reduce the design cycle time and cost. It can be effectively used for optimizing the die design in order to

improve quality, optimizing process parameters without any physical tool build.

ACKNOWLEDGEMENTS

The authors would like to thank NRB management especially Mr. S T Salunke, G.M. Engineering for his sustained motivation and support throughout the project. In the end, the authors would like to thank Altair and design tech

team for their invaluable guidance and focus on the completion of this project.