Oct 17, 2015
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 [email protected]
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.