Abstract: Lightweight thin-wall cylinder parts are difficult for heavy lathe processing,especially for high-precision cylinder with deep blind holes. This paper introduces the manufacturing process of deep blind hole in cylinder block,especially the machining process of high precision hole bottom arc and bottom surface. In order to solve the problem of alignment of the cylinder block on the heavy-duty lathe clamping clamp,the cylinder block support frame sleeve was reformed and designed,and the cylinder block and support sleeve were assembled and hoisted to the machine tool to ensure alignment error less than or equal to 0.05mm. The boring bar is installed on the machine tool and the guide wood is installed on the boring head to finish the finishing of the deep blind hole. In order to solve the problem of deep hole bottom arc R60 and hole bottom surface roughness Ra3.2,the existing tool was reformed,and the hole bottom arc R60 and hole bottom surface were roughed and semi-finished. At the same time,the combined special tool was designed and manufactured to be installed in the tool holder,and the feed was recorded with a scale to finish the hole bottom arc R60 and hole bottom surface. Through the manufacturing of the deep blind hole,the dimensional accuracy of the deep blind hole is finally guaranteed,and the roughness requirements of the bottom arc R60 and the bottom surface of the hole are also guaranteed. The processing efficiency is improved,the processing cycle is shortened,the manufacturing cost is reduced,the assembly performance requirements are met,and the product quality is guaranteed.

Key words: deep blind hole of cylinder block, cylinder block support frame sleeve, hole bottom arc, roughness of hole bottom surface, combined cutting tool, accuracy of dimensions