Materials, Methods & Technologies, Volume 6, 2012

Rezumat: This paper presents a method for designing a single punch tool intended to restore worn elements of broached parts through controlled plastic deformation. The authors analyze how metal flows during broaching type pressing, showing that deformation creates a characteristic gap between the punch and the restored surface that must be compensated to achieve a reliable non separable joint. A staged restoration sequence is proposed: initial insertion of the punch into the worn zone to obtain the required shape change, thermal stabilization to avoid loss of punch strength due to heat transfer, and final upsetting to fill the gap and complete the joint. Design calculations are developed for the deforming volume and the additional compensating volume, and the relative metal volume needed for compensation is expressed via a regression model based on punch diameter, cone angle at the base, and penetration depth, obtained from Deform 2D simulations across multiple factor levels. Practical guidance is also provided on selecting the punch end geometry to minimize required forming forces, recommending a conical end for open broaching conditions and a flat end for closed broaching to reduce deformation loads.