Scratches

Cause：

1) the particle size of polishing powder is uneven or mixed with large particle mechanical impurities

2) the workshop environment is not clean

3) the polishing materials (polishing glue or polyurethane and adhesive, etc.) are dirty

4) dirty wiping cloth and dust brought by the operator

5) scratches left by fine grinding are not thrown away or are not thoroughly cleaned

6) the inspection aperture workpiece or template is not clean and the method is improper

7) the polishing material (polishing glue or polyurethane) is hard and has been used for a long time,there are hard shells on the surface or dry and hard deposits on the edge

8) the polishing die is not consistent with the mirror disk

9) caused by auxiliary processes (footwall, cleaning, turnover, wet protective paint, etc.)
Overcoming Methods :

1) select polishing powder with uniform particle size and corresponding to glass material

2) do a good job of "5S"

3) keep the necessary supplies

4) cleaning and storage of wiping cloth and operators wearing work clothes and hats

5) self inspection

6) use the template correctly

7) select appropriate polishing materials (polishing glue or polyurethane), replace them periodically, and modify or repair the polishing die

8) modify or scrape, and remake the polishing die

9) process according to the operating procedures of each auxiliary process
Pitting

Cause :

1) insufficient time for fine grinding and polishing

2) the fine grinding surface is uneven or the difference between the middle and the edge is large

3) there are traces after rough scratches are broken

4) square or rectangular angle collapse after fine grinding

5) parts move on the mirror disk due to processing

6) the shape error of fine grinding surface is too large, especially the height is too high, which is easy to cause insufficient edge polishing

7) the polishing efficiency is affected by the long processing time of the polishing die or the long use time of the polishing liquid

Overcoming Methods：

1) the last coarse sand hole shall be removed during fine grinding, and the polishing time shall be sufficient

2) the fine grinding aperture is properly matched, and it should be processed from the edge to the middle

3) after finding it, it should be marked, placed separately or re thrown

4) use slotted flat mold, fine mold and add sand evenly

5) select appropriate adhesive, control the process temperature and the temperature of the mirror plate, and the thickness of adhesive should meet the standard

6) the aperture matching of each channel of fine grinding shall be carried out in strict accordance with the process operation instruction card

7) periodic management of various indicators (specific gravity, pH value, etc.) of replacing polishing leather and polishing fluid.

Imprint

Cause :

1) the polishing die is not well matched with the mirror disc, and there are traces of oil spots

2) poor chemical stability of glass

3) water drops, polishing fluid, saliva, etc. are not wiped clean in time

Prints are mostly produced in glass with poor chemical stability. The role of additives is mainly to stabilize the pH value of polishing solution and increase some hydrophobic substances left on the surface of the lens, so as to enhance the water resistance of the lens In addition to additives, heat output during processing should be minimized.
Overcoming Methods：

1) select appropriate polishing glue, scrape or modify (polyurethane) polishing mold to make it match

2) appropriate additives can be selected for the imprint generated in polishing; and the mark produced after completion can protect the paint

3) avoid speaking to the workpiece; if the following plate cannot be wiped dry, it should be wiped clean. The glass with poor chemical stability should also be dried.
Aperture Deformation

Cause :

1) improper bonding force of adhesive

2) the aperture is not stable

3) when the rigid disc is processed, the rigid disc has been used for a long time and has not been detected (the counterbore is dirty or deformed)

4) the outer circle of the workpiece to be processed is too large during rigid disk processing, and the hanging method is improper, etc.

Overcoming Methods:

1) aperture deformation mainly occurs in thin parts or irregular parts, and appropriate hanging method shall be adopted

2) a certain aperture stabilization time shall be given according to the size of the workpiece

3) the rigid plate shall be tested and corrected regularly

4) strictly follow the process and hanging wall operation procedures