The method of determining the accuracy of polymer molds in plaster forms has been discussed. Distortion of the surface of molds and plaster molds has been assessed. It has been found that the presence of monolithic and porous structure in the samples does not change the accuracy of the surfaces when forms are prepared for removing the material of the model. It has been found that in case of full-mold casting it is more expedient to form the mold cavity with cellular adjustable structures of molding prototypes.
This paper shows the results of studying the technology of manufacturing cortical electrode-instruments (EI) with the use of indirect methods of the Rapid Prototyping technology. Functional EI prototypes were made by layered synthesis of the photopolymer material with the use of the stereolithography technology (SLA - Stereo Lithography Apparatus). The article is focused on two methods of indirect EI manufacturing. One of the EI prototypes was used for making a molded wax model for hot investment casting, followed by applying copper coating. The second prototype was used for applying copper plating to a prepared current-conductive layer. As a result of EDMing a steel workpiece, both EIs reached the desired depth, which is 1 mm. The copper plating applied to the EI preserves its integrity. Through the use of the casting technology, there is a possibility to cut the economic costs by 35%. Using a prototype with preliminarily applied conductive coating makes it possible to make geometrically-complex EIs.
This work presents a scheme for the manufacture of spherical grinding bodies used in grinding and crushing machinery as a grinding medium from abrasion-resistant cast iron CHKH16 (according to GOST 7769-82) free of shrinkage defects produced by casting into single sand molds with a vertical joint and by usingcoolers. The grinding efficiency in terms of material destruction and energy consumption has been studied according to a wide range of operating parameters and new scheme for calculating the sprue and supply system has been developed by the authors of the article. Its functionality has been substantiated, particularly the use of a central riser acting as a head and the use of coolers. The conducted numerical simulation has shown the dependence of a solid phase formation over time, which characterizes the direction of the system crystallization and determines the locations of the shrinkage defects concentration. The manufacture of the grinding body with a 100 mm diameter using the considered technology is presented in this paper.