Yoshio Hasegawa

Moldability of Long Glass Fiber Mat Reinforced Polypropylene Resin Sheet to a Cupped Part.

Long glass fiber mat reinforced polypropylene resin sheet is one type of stampable sheets. The stampable sheet is easily formed into a part, but it has some problems in the processing. So, in this report, the effects of molding conditions on the moldability were investigated. That is to say, the effect of the heating temperature, the heating time, the mold temperature and the charge pattern on the strength and the surface roughness were investigated in details, when the cupped parts were molded. The main results obtained are as follows: 1) The most suitable heating conditions of the stampable sheet blank are 230°C and 5 min. 2) The part made from 4 pieces of ply has the highest strength. 3) In the case of the mold temperature below 100°C, the higher the mold temperature is, the better the surface rouhness of part is. 4) The part under the mold temperature 150°C had the highest strength.

Effect of surface-pretreatment on adhesive strength of hard chromium plating.

Testing the adhesion between chromium plating and the base metal involves many difficulties, and the conventional test is too inaccurate to permit analysis of adhesion. For this reason an improved adhesion test, based on the drawing method developed by R. A. F. Hammond et al., was used to measure the strength of adhesion of chromium plating to the base metal. As the hydrogen overvoltage on the base metal surface to be plated seems to have a great effect on the mechanism of electrodeposition in chromium plating, it was measured to clarify the chemical characteristics of the surfaces, and the adhesion mechanism was considered.It is considered that the condition of the base metal surface to be plated influences the structure of the metal deposited at the first stage of the electrodeposition, and that the strength of adhesion of the plating to the base metal varies. If the base metal surface is etched by counterelectrolysis in the chromium plating bath just before plating, the base metal surface becomes favorable for plating. This etching process causes stronger adhesion of chromium plating to the base metal.

Effect of lubricating methods on dimensional accuracy and surface roughness of drilled holes in aluminum alloys

The forced, mist, and conventional lubricant supply methods were applied to a drill with an oil supply hole and a pointed chisel edges. The effect of the above lubricating methods on the hole accuracy was examined in terms of the hole oversize, the surface roughness and the height of burr. Although a soft alloy did not discriminate the lubricating methods, the forced lubrication was most efficient in the drilling of a hard alloy. When the drilling was performed under the severe condition, the effect of the forced lubrication was prominent. It was found that the hole accuracy was improved irrespective of the lubricating method, if the outer corner of the drill lip with a large relief angle was rounded to an adequate degree.

Studies on hole accuracy in drilling of aluminum its and alloys

The normal drill grinder with a stepped ground point drill having a chisel edge angle of 90° can drill smaller dimensions of oversize of holes than with the conventional chisel point drill.However, the optimum condition of drilling aluminum and its alloys by using the drill of the former type is still unknown. This paper discusses the effects of drilling conditions and the shapes of drill points on the dimensions of oversize of holes for materials of 5 kinds of F-metals; 1S, 2S, 17S, 52S, and 61S.The principal results obtained were as follows.(1) In dry drilling (with no cutting fluids), the dimensions of the oversize were arranged in ascending order of 17S<52S<61S<aluminum.(2) In drilling of aluminum, the point angle was obliged to be smaller for decreasing the dimensions of oversize. In drilling of aluminum and its alloys, the pointed chisel drill was effective in decreasing the dimensions of oversize.(3) In dry drilling of aluminum, the dimensions of oversize were decreased with the increase of feed, but were little affected by cutting speed except for the case of 1S.(4) The effects of cutting fluids on dimensions of oversize were sometimes different between drilling of aluminum and its alloys. However, emulsions were effective in drilling of the both materials.