The grinding wheel spindle always maintains high rotation accuracy, rigidity and working stability. And the grinding wheel carriage is driven to feed by the ball screw. The guide rail of the grinding wheel frame adopts linear rolling steel guide rail. The worktable adopts a double-layer structure to facilitate the adjustment of the precision of the cylindrical grinder. The upper rotating worktable can grind conical parts. The AC servo motor is used to directly drive the ball screw pair to control the movement of the worktable. The worktable guide rail is a plastic sliding guide rail, and the cooling system is equipped with an independent cooling water tank to further ensure the grinding quality. Grinding the four planes of the square-cut monocrystalline silicon or the polycrystalline silicon cuboid silicon block after the square cut, chamfering and rounding the four right-angle sides. Grinding, chamfering and rounding can be completed in one clamping. The surface finish of the silicon block is improved, the microcracks formed on the surface of the silicon block during the warp cutting process are corrected, and the yield of the silicon block slice is improved.