Solid State Phenomena Vol. 311

Abstract: This study investigated the effects of the die clearance on the shearing and shaving processes of the stainless steel (SUS316LVM) wire at micro scale. A die set was developed and installed on a precession press equipped with a load cell and a displacement sensor to conduct experiments. By using different punches in the same die set, the specimens prepared from 316LVM stainless steel wires with 0.5 mm diameter were first sheared and then shaved. Experimental results show that the burnished area of the sheared edge increases with the reduction of the clearance between the punch and die in the shearing process. The clearance also significantly affects the load curves. Moreover, the shaving process does increase the burnished area on the shaved edge of the specimen. By an appropriate feed in the shaving process, it is possible to trim the extra material from the sheared edge that results in a nearly complete burnished surface on the shaved edge of the stainless steel wire. This research provides a basis for understanding of the die clearance effect on the shearing and shaving processes at micro scale.

Abstract: A novel micromachining technology is investigated in this work. Precision machining of micrometer sizes can be achieved by a tool scraping on CNC machine. The knife for scraping with small knife nose with radius of fifty micrometer can scrape surfaces of designed function by path planning of CNC machine. To investigate performance, micro channels are scraped on workpieces by micro shaping. For tool path planning, feeding rate and scraping depth have significant effect on machining performance and depth-to-width ratio. Poly-methyl methacrylate (PMMA) and aluminum alloy are materials for scraping. From the results of experiments, aluminum alloy has better machining performance and smoother scraping surface than PMMA. Smaller scraping depth would induce better performance and size precision. For feeding rate, 800 mm/min is better for PMMA and 500 mm/min is better for aluminum alloy.

Abstract: In this paper, non-isothermal analysis of an automatic multi-stage cold forging process of a ball-stud is conducted using a new material model which is a closed form function of strain, temperature and strain rate covering low and warm temperatures for high-strength stainless steel SUS304. An assembled die structural analysis scheme is employed for revealing the detailed die stresses, which is of great importance for process and die design for metal forming of the materials with high strengths. Die elastic deformation is dealt with to predict final geometries of material with higher accuracy. A complete analysis model is proposed to be used for optimal design of process and die designs in automatic multi-stage cold forging of high-strength materials.