Comparison of ironing finishing and compressing finishing as post-forging for net-shape manufacturing

Net-shape forging is a high-efficiency and low-wastage process. However, it presents numerous disadvantages, such as low precision and surface quality of hot forging, as well as high load and harsh die quality of cold forging. Cold finishing is applied as a post-forging operation of forged gears. A hot-forged helical gear is processed by ironing finishing and compressing finishing that is introduced in this paper. A tool set is designed to compare compressing finishing with ironing finishing through experiments and finite element simulation. This study reveals that the load of ironing finishing is not related to interference. Moreover, the difference in tooth shape and surface roughness of both tooth surfaces of each gear is due to the helix angle. Excessive finishing leads to surface quality degradation. The load of compressing finishing increases linearly. Surface roughness evidently improves, and it is not related to the amount of compression. The helical line of the gear by ironing finishing exhibits a crown shape, which is the result of end-effect of compressing finishing.

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