18-06-2013, 12:14 PM
Design and Analysis of Progressive Tool
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ABSTRACT
Design and development of Progressive tools for the sheet metal component is one important phase in sheet metal manufacturing. Sheet metal press working process by progressive tools is a highly complex process that is vulnerable to various uncertainties such as variation in progressive tools geometry, strip layout, die shear, material properties, component and press working equipment position error and process parameters related to its manufacturer. These uncertainties in combinations can induce heavy manufacturing losses through premature die failure, final part geometric distortion and production risk.
Identification of these uncertainties and quantifying them will facilitate a risk free manufacturing environment, which goes a long way to minimize the overall cost of production. FEM based modelling of press working process is a very effective tool to overcome the above uncertainties.
INTRODUCTION
The progressive die performs a series of fundamental sheet metal working at two or more stages during the press running to produce a production part as the strip stock moving through the die surface. Press working from the optimum dies design and its making has been the purpose of mass production in the manufacturing field. The design and manufacture of press tools, or punches and dies, is a branch of production technology that has extended into many lines of engineering manufacture over the past seventy years. There is no doubt that the accuracy achieved by new ideas in design and construction applied by the press tool designer, coupled with increased speed and rigidity of the presses etc, used have all contributed towards maintaining this form of metal tooling well to the force as a means of obtaining pleasing, yet strong, durable articles that can withstand severe day-to-day usage.
PROGRESSIVE TOOL
Progressive tool performs two or more operations at different stages in each stroke. The stock strip is advanced through a series of stations that form one or more distinct press working operations on the strip to get the component.
Loads
Load for some function elements like top half, bottom plate and die plate are applied on Fz positive direction of magnitude as 80% of cutting force as vertical. And for punches like piercing punch, oblong piercing punch, notching punch and blanking punch are applied on Fz positive direction of magnitude as calculated cutting force of that operation as compressive load on surface. And also for guide pillar load applied is on Fx positive direction of magnitude as 10 to 20% of cutting force as thrust load and Fz positive direction of magnitude of 80 to 90% of cutting force as vertical load.
CONCLUSION
The individual components of progressive tool were modelled in Pro-Engineer 4.0. Each individual file was imported to Ansys12.0 software through Initial Graphics Exchange Specification (IGES) format. The following conclusions were made.
1. The results obtained through analysis are approximately nearer to the theoretical values. This demonstrates that the analysis carried out was correct.
2. It is also observed that the design of progressive tool is safe as all the stress values were less than the allowable stress of the material.