Abrasive belt wear precautions

There are two basic applications of abrasive belt grinding, namely light-weight grinding and heavy-weight grinding. Lightweight grinding removes very little material, and can only play the role of surface pre-processing or workpiece finishing, such as polishing, deburring, etc. The abrasive belt grinding speed is faster during light-weight grinding. Weight grinding plays a role in rough and fine machining of the workpiece. Its advantages are high cutting rate, low cutting heat, small workpiece deformation, and easy control of flatness and surface roughness.

Contact wheel grinding and free grinding are the two major processes of abrasive belt grinding. The former is suitable for rough grinding, semi-finishing and fine grinding, and the latter is also used for semi-finishing and fine grinding, but mainly for polishing. effect.

Abrasive belt grinding can improve the machining accuracy, which is controlled by the profiling method and the fixed-length machining form. The profiling control is to use the template plate to properly control the feed speed in the tangential direction during grinding within a certain range, so that the workpiece can be ground corresponding to the template plate; fixed-length processing is based on the workpiece width and machining allowance changes. , Control the feed speed of the workpiece properly, control the normal grinding resistance to a certain extent, and maintain the grinding residue to a certain value (not zero).

Belt grinding should pay attention to the following matters:

(1) Grinding depth When grinding the abrasive belt, due to the elasticity of the contact wheel, the feeding depth is different from the actual depth, and the ratio is about 3:10

(2) The initial grinding position of the new abrasive belt Because the amount of removal of the new abrasive belt is more than that of the old abrasive belt, the initial grinding position of the new abrasive belt cannot be fixed. The geometric accuracy can be improved by frequently measuring the outer diameter, identifying the Z-large outer circle from which the new abrasive belt is initially fed, or by repeatedly grinding it.

(3) In order to improve the surface roughness of the workpiece by non-feed grinding, it can be used back and forth 3 to 4 times without feeding after fine grinding, and the effect is very good.

(4) Machining allowance The general abrasive belt grinding allowance is 0.04 to 0.08 mm. When the surface roughness value before grinding is higher than Ra2.55m, the machining allowance can be slightly more. The surface roughness value before free polishing is Ra 1.255m-RaO.635m, and the machining allowance is 0.01-0.02mm.

In addition, because the abrasive cutting edge of the new abrasive belt is very sharp, and the height is different, only a part of the cutting edge works, which affects the roughness of the workpiece surface. Therefore, the abrasive belt must be trimmed to make all the cutting edges processed. There are two dressing methods: ① wrap the old abrasive belt on the round wooden stick, hold the wooden stick with your hand, and grind the new abrasive belt rotating on the contact wheel. At this time, the force should be appropriate; ② in the semi-fine grinding In the process, the selected new abrasive belt will be used for grinding, and the cutting edge will be slightly blunt, and then replaced for fine grinding.