The surface grinder can be divided into two types according to the shape of the worktable: rectangular worktable and circular worktable. The main parameters of the rectangular worktable surface grinder are the width and length of the worktable, and the main parameters of the circular worktable are the diameter of the worktable. According to the different types of shafts, it can be divided into horizontal shaft grinder and vertical shaft grinder. So what are the tips for grinding the mirror? Now let's have a look!

1. Requirements for grinding machine

The coaxiality of the machine tool spindle should be good, and the machine bed should be stable, otherwise there will be chattering lines. The rotation accuracy of the grinding wheel spindle is higher than 1 μ m； The amplitude of the grinding wheel holder relative to the workbench is less than 1 μ m； The cross feed mechanism can move precisely; There is no creeping phenomenon when the workbench moves at low speed.

2. Requirements for grinding wheel

The grain size of the grinding wheel shall be less than W15 (the grain size of the grinding wheel shall be less than 15 μ m) The grinding wheel shall be trimmed flat. It is easy to burn a knife if it is thin, but it has lines if it is rough).

(1) Balancing wheel

After the grinding wheel is installed with flange, rough static balance shall be carried out first, then the grinding wheel shall be installed on the grinding wheel shaft to trim the two end faces and the outer circle, and finally accurate static balance shall be carried out.

(2) Dressing wheel

1) Generally, the fine grinding allowance is 0.015~0.02mm. When the workpiece is roughly ground to Ra0.8, the fine grinding allowance is 0.005~0.015mm (the grinding allowance must be determined according to the steel property and hardness. For steel with high hardness and easy to polish, the grinding allowance should be appropriately reduced), the fine grinding wheel is required.

2) When finishing the grinding wheel, first knock off the thickness of about 0.1mm, then trim it twice with a cutting depth of 0.02mm, trim it three times with a cutting depth of 0.01mm, and finally reciprocate twice without cutting depth. The cross feed speed during fine trimming is 20~30mm/min. For mild steel workpieces, the cross feed is better when grinding the grinding wheel, but the opposite is true when machining hardened high speed steel.

3) When dressing the grinding wheel, enough grinding fluid or other coolant must be used to wash on the contact point between the grinding wheel and the diamond cutter, so as to wash away the grinding wheel debris in time, so as not to affect the grinding quality.

4) The diamond cutter used for fine trimming does not need to be very sharp, because the grain size of the grinding wheel is relatively coarse. The diameter of the diamond tip can be within 0.8mm. When dressing with a sharp diamond cutter, the cross feed speed must be reduced.

5) When the new dressing wheel is used, the surface roughness is slightly worse, and it will be stabilized after a while.

3. Grinding amount

1) The cutting amount of the grinding wheel back of the grinder is about 0.005mm. Increase or decrease appropriately according to the properties and hardness of the workpiece steel. For example, for hardened steel with high hardness, excessive back cutting is easy to cause burns, while for mild steel, too small back cutting is not easy to polish.

2) The single travel of cross feed is 0.2~0.4 mm. The cross feed speed has a great influence on the surface roughness, because the cutting ability of the mirror grinding wheel is very poor. If the cross feed speed increases, the wheel surface will be damaged, so a very smooth surface cannot be obtained.

3) The longitudinal feed rate is 12~15 m/min. Longitudinal feeding has little effect on the surface roughness, but if it is too slow, the workpiece surface will produce ripples or patterns.

4) Due to the poor cutting ability of the grinding wheel during mirror grinding, tool marks (moon shaped circular workpiece and belt shaped rectangular workpiece) often appear on the workpiece surface, which reflects that the workpiece surface is not straight, so it is necessary to conduct non feed polishing for about two minutes.

4. Flushing

When grinding, flush water. Before grinding, clean the water tank, grinding wheel cover and water tank of the machine table. Use filter paper and magnetic filter.