الفهرس 
ARABIC SUMMARY
Power pressesOnly 14 pages are availabe for public view
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Abstract
The experiments described in this work have yielded valuable results of immediate benifit to the press work. The study of the factors governing the formation of the sheared surface in conventional piercing for thick plates, showed that cracking could be prevented by changing the die fillet radius and by allowing a hydrostatic pressure on the stressed system to built up, so that seperation is com;eted by plastic flow. The analysis of the stress conditions at the cutting edge during the piercing operation led to the development of a new cutting tool, which gave a smoothly sheared surface with as minimum work as possible.
Sata on surface formation stages, dimensional accuracy, surface roughness and the out of roundness are given for the pierced holes, for both aluminium sheets of 10mm thick and steel 50 sheets of 8 mm thick.
The results of measurements of the maximum cutting and backstroke forces & works for conventional and developed tools are also given.
The new developed piercing method, which is xalied extrusion piercing, can be readily applied in the production plate without appreciable extra costs.