Grind

Classification

Polishing method can be divided into wet grind, grind and semi-dry grind three categories.

Wet grind: also known as deposited sand grinding, the liquid filling or coating in a continuous Abrasive grinding surfaces, abrasive between the workpiece and the lap 

constantly sliding and rolling, forming cutting motion. Wet research generally used for rough grinding, abrasive powder used in coarse granularity.

Dry research: also known as embedded sand grinder, the uniformity of the pressure abrasive embedded in the surface layer of the lap, the lap polishing the surface only 

a small amount of stearic acid coated with fat and other auxiliary materials. Commonly used in dry grind fine grinding, fine grain abrasive powder used in.

Semi research: Similar to wet grind, the use of abrasive grinding paste is a paste. Grinding either by hand, but also on the grinding machine. Polishing the workpiece 

by other processing methods required before pre-processing to obtain a higher accuracy, the left margin is generally abrasive 5-30 microns.

RESEARCH abrading tool is a tool of the workpiece, is also the carrier of the abrasive, hardness should be less than the hardness of the workpiece, has a certain wear 

resistance, commonly made of gray cast iron. Wet lap metallurgical research organizations based ferrite; dry research lap places of uniform and fine pearlitic matrix. 

The following grinding M5 thread and small parts of complex shape, the commonly used mild steel lap. Grinding holes and soft metal material, mostly made of brass, 

copper lap. Should have sufficient stiffness lap, the working surface to have a high geometric precision. Lap during the grinding process has also been cutting and 

wear, such as operating properly, its accuracy can be improved, so that the machining accuracy can be higher than the lap of the original accuracy.

To correctly handle abrasive grinding trajectory is to improve the quality of the important conditions. In the surface grinding, the general requirements: ① movement 

of the workpiece relative to the lap, to try to ensure that each point on the workpiece grinding stroke of similar length; ② trajectory workpiece uniformly throughout 

the surface of the lap, to facilitate uniform wear lap; ③ movement trajectory curvature changes should be small, in order to ensure smooth movement of the workpiece; 

④ any point on the trajectory of the workpiece to avoid premature periodically repeated. Pictured common plane grinding trajectory. To reduce the thermal cutting, 

grinding is generally carried out under low pressure. Rough grinding pressure of not more than 0.3 MPa, lapping pressure is generally 0.03 to 0.05 MPa using. Coarse 

grind speed is generally 20 to 120 m / min, lapping speed generally take 10 to 30 m / min.

Grinding - Methods

1) Cylindrical Grinding

Description: ① generally cylindrical grinding or polishing finishing basis. Hand grinding cylindrical in lathe, painted between the workpiece and the lap abrasive 

workpiece is rotated by the lathe spindle, and research support for axial reciprocating with hand movement. ② mechanical grinding cylindrical grinding machine for the 

general class of balls for grinding cylindrical parts.

2) grinding the inner circle

Description: Grinding inner circle need grinding, precision hinge or fine boring after, usually hand-grinding. Sleeve for the opening lap, set in the taper mandrel 

abrasives applied between the workpiece and the lap, holding the workpiece axially reciprocated. Grinding after a certain time, the direction of the large end of the 

taper adjustment spindle sleeve, the diameter of the swell, to maintain pressure on the workpiece bore wall.

3) ground plane

Description: ground plane is generally carried out after grinding. Hand grinding plane, coated abrasive grinding plate (lap) and holding the workpiece in a straight 

line reciprocating or "8" motion. Grinding after a certain time, the workpiece is turned 90 ° ~ 180 °, to prevent the workpiece tilt. Study of the workpiece to be 

small locally planar, square hole, slit and other surfaces, can be hand-held grinding lap. Larger quantities of simple parts on a plane in the plane grinding machine 

can grind.

Grinding - Process Characteristics and Applications

① simple equipment, less precision.

② processing and reliable quality. Obtain a very high precision and very low Ra value. But generally can not improve the processing surface and the other surface of 

the positional accuracy.

③ process a variety of steel, hardened steel, cast iron, copper and aluminum and its alloys, tungsten carbide, ceramic, glass and some plastic products.

④ grinding is widely used in single and small batch production and processing of various high-precision surface, and can be used in a large number of mass production.