Spare Parts Processing Are Based On The Research And Application Of Blank Dimensions Of The Benchmark

With the increasingly fierce competition in the market, in order to maintain theircompetitiveness, many enterprises have to be constantly in pursuit of high efficiency and lowcost. As the first step of machine manufacturing, manufacture of blank is the key link toquality and cost of product. But the blank dimensions error and form and position error arelarge, the surface roughness is high, people do not pay much attention to the problem ofselection of blank design bench-mark and its manufacturing process.Technician are used to take the part design bench-mark as the blank bench-mark. But theselection of part design basis should accord with the principle of ensure the assemblyprecision. The blank design should focus on how to ensure the precision and rough machiningallowance of all the size and the surface shape accuracy. So the design of blank should basedon the machine process. Then we can understand that it is unreasonable to take parts designbasis as blank design basis.In this paper, from the perspective of ensure the rough machining allowance precisionand position precision between the machining surface and unfinished surface, I discuss therationality of take rough benchmark as blank design. Then take crankshaft, shell, lever andhole components as example, I discuss how to label linear and flat blank dimension. At last,taking pump body blank as example, I discuss the reasonable selection of locating basis ofsand mold and sand core. From the principle of locating, I discuss the reasonable structure ofsand core print. To illustrate the point of view, this paper adopted the principles size type, sizeof tree graph, the graph theory methods such as path graph analysis and assembly size.This article main research work in the following aspects:(1) Analyzing the rationality of taking rough benchmark as blank dimension’s designbenchmark. By taking some examples, I discuss the logical mark mode of linear blankdimension;(2) Through the example of holes parts, I analysis the reasonable selection of designbenchmark and the logical mark mode;(3) Discussing the reasonable selection of locating basis of casting blank cavity and sand core and the reasonable structure design of sand core point; Using the idea of Schematics ofAssembly Dimension Route, I discuss the method of quick acquire the functional dimensionsof sand cavity and sand core.