Finishing of the finished surface with whetstones (also known as honing sticks) embedded in the honing head. Also called boring. It mainly processes various cylindrical holes with a diameter of 5 to 500 mm or more, and the ratio of hole depth to diameter can reach 10 or more. Under certain conditions, it can also process plane, outer circular surface, spherical surface, tooth surface, etc. The periphery of the honing head is inlaid with 2 to 10 whetstones with a length of about 1/3 to 3/4 of the hole length. When honing the hole, it both rotates and moves back and forth, and at the same time, it expands evenly through the spring or hydraulic control in the honing head. Therefore, the contact area with the hole surface is larger, and the processing efficiency is higher. After honing, the dimensional accuracy of the hole is IT7-4, and the surface roughness can reach Ra0.32-0.04 microns. The size of the honing allowance depends on the hole diameter and workpiece material, generally 0.02 to 0.15 mm for cast iron and 0.01 to 0.05 mm for steel. The speed of the honing head is generally 100-200 rpm, and the speed of the reciprocating motion is generally 15-20 m/min. In order to flush away chips and abrasive particles, improve surface roughness and reduce the temperature of the cutting zone, a large amount of cutting fluid, such as kerosene or a small amount of spindle oil, is often used during operation, and sometimes extreme pressure emulsion is used.
Grinding:
Finishing processing (such as cutting) of the machined surface through the relative movement of the grinding tool and the workpiece under a certain pressure by using abrasive particles coated or pressed on the grinding tool. Grinding can be used to process various metal and non-metal materials, and the surface shapes processed include plane, inner and outer cylindrical and conical surfaces, convex and concave spherical surfaces, threads, tooth surfaces and other profiles. The machining accuracy can reach IT5～01, and the surface roughness can reach Ra0.63～0.01 micron.