Magnetorheological finishing of micro-punches for enhanced performance of micro-extrusion process

ABSTRACT

The modern trend toward miniaturization has provided an innovative push toward the creation of micro-fabrication parts. Micro-extrusion is one such emerging process. It finds its various industrial applications in mechanical, electronic and micro-fabrication parts. Micro-punches are the main part of the micro-extrusion process. In the extrusion process, high contact forces are generated due to the sliding between the punch and billet. These high contact forces are governed by the surface topography of the punch. When the punches are finely finished, lesser contact forces are generated. To fulfill this requirement, the rotating rectangular core magnetorheological finishing process is used. On the basis of the applications, four industrial micro-punches are used for the present investigation. After MR finishing, surface roughness values of the micro-punches of the initial ground surface 0.210, 0.230, 0.250 and 0.200 µm are reduced to 0.02, 0.02, 0.03, and 0.01 µm. The operative functionality of the magnetorheological finished micro-punch is examined for its improved performance in the micro-extrusion process. The decrease in the roughness value reduces the frictional force between the micro-punch surface and the billet. Improvement in surface topography of the magnetorheological finished micro-punches enhances the quality of the product outcome and more uniform deformation of billet material.

KEYWORDS:

• Magnetorheological
• finishing
• micro
• punches
• extrusion
• processes
• friction
• surface
• roughness