Grinding is an abrasive precision machining method that uses a grind tool and abrasive to grind off a very thin layer of metal from the surface of the workpiece on the basis of fine machining. The dimensional tolerance grade can reach IT5～IT3, and the Ra value can reach 0.1～0.008μm.
1. Types of grinding
① Wet research
The liquid abrasive is coated or continuously injected on the surface of the grinding tool, so that the abrasive (W14～W5) continuously slides and rolls between the workpiece and the grinding tool, thereby realizing the cutting of the workpiece. There are many wet research applications.
② Qianyan
Press the abrasive (W3.5～W0.5) evenly on the surface of the grind tool, and apply a small amount of lubricant on the surface of the grind tool during grinding. Dry research is mostly used for fine research.
③ Semi-dry research
The abrasive used is a paste-like abrasive paste, both coarse and fine grinding can be used.
2. Grinding principle
① Micronity: It can cut the workpiece from 0.01 to 0.1μm.
② Randomness: the workpiece and the research tool are in random contact, the high points are trimmed each other, the error is gradually reduced, and the accuracy is improved at the same time.
③ Pertinence: It can detect the workpiece, change the grinding position and control the grinding time in a targeted manner to ensure the accuracy of size and shape.
3. Grinding materials and abrasives
1) Research tool materials
Cast iron: grinding hardened and unhardened steel and cast iron parts.
Brass: Grinds various soft metals.
2) Abrasive
① Abrasives: alumina, silicon carbide, iron oxide, cerium oxide, etc.
② Grinding fluid: engine oil, kerosene, animal oil and oleic acid, stearic acid
4. Grinding method
Description of the grinding plane: The grinding plane is generally performed after fine grinding. When manually grinding the plane, the abrasive is coated on the grinding plate (grinding tool), and the workpiece is held in a linear reciprocating motion or “8”-shaped motion. After grinding for a certain period of time, turn the workpiece 90°～180° to prevent the workpiece from tilting. For the small planes, square holes, narrow slits and other surfaces on the workpiece to be ground, the grinding tool can also be used for grinding. The flat surface on simple parts with larger batches can also be ground on a flat surface grinder.
Grinding plane Grinding groove
5. Grinding process characteristics and applications
① The equipment is simple and the precision is not high.
② Reliable processing quality. High accuracy and low Ra value can be obtained. However, the position accuracy between the machined surface and other surfaces cannot generally be improved.
③ It can process all kinds of steel, hardened steel, cast iron, copper-aluminum and its alloys, cemented carbide, ceramics, glass and some plastic products.
④ Grinding is widely used to process various high-precision profiles in single-piece and small-batch production, and can be used in mass production.