Microstructure and M echanical Properties of Magnesium Alloy Sheet by Friction Heating Single Point Incremental Forming

By friction heating single point incremental forming,truncated square pyramid parts with different draw angles of a magnesium alloy AZ31 B were formed at room temperature.Metallurgical,tensile and micro-hardness tests were carried out to obtain the effects of wall angle on microstructure and mechanical properties. The results show that grain in side wall of the formed parts becomes refined significantly. Furthermore,with the increase of draw angle,grain size increases,but strength,hardness and plasticity decrease. In addition, surface roughness tests were performed on the formed surface to determine the influence of speed of forming tool. The results show that surface roughness has a little increase with the increase of tool rotational speed.

A Hybrid Optimization Approach of Single Point Incremental Sheet Forming of AISI 316L Stainless Steel Using Grey Relation Analysis Coupled with Principal Component Analysiss

We investigated the parametric optimization on incremental sheet forming of stainless steel using Grey Relational Analysis(GRA) coupled with Principal Component Analysis(PCA). AISI 316L stainless steel sheets were used to develop double wall angle pyramid with aid of tungsten carbide tool. GRA coupled with PCA was used to plan the experiment conditions. Control factors such as Tool Diameter(TD), Step Depth(SD), Bottom Wall Angle(BWA), Feed Rate(FR) and Spindle Speed(SS) on Top Wall Angle(TWA) and Top Wall Angle Surface Roughness(TWASR) have been studied. Wall angle increases with increasing tool diameter due to large contact area between tool and workpiece. As the step depth, feed rate and spindle speed increase,TWASR decreases with increasing tool diameter. As the step depth increasing, the hydrostatic stress is raised causing severe cracks in the deformed surface. Hence it was concluded that the proposed hybrid method was suitable for optimizing the factors and response.

Single point and asymmetric incremental forming

This paper presents an update on single point incremental forming （SPIF） of sheet metal since 2005. It includes a description of the process with new information on the maximum forming angle, Фmax, for 5052-H32. An indepth example of the successful design and production of parts is given for industry. This includes discussion on production times and surface roughness with details that will help designers. A general design guide for users of SPIF is provided. It is based upon experience gained in the last decade. In general, materials show a trend of decreasing formability with increasing initial thickness. It is shown that for thicker sheet metal, it is recommended using large spherical tools （12.7 mm or larger）, or a large fiat-ended tool. The fiat-ended tool provides the best combination of good formability and very low surface roughness. For aluminum, galvanized steel and stainless steel, it is recommended using a fiat-ended tool. Advances in multi-pass techniques and information on successful and useful numerical models which predict forming behaviour are included. Finally, there is a discussion on future work needed in SPIF.