Due to improper selection of grinding (polishing) light wheel, grinding (polishing) light and polishing agent, especially when the polishing pressure is too large or the grinding time is too long, the surface of the workpiece tends to leave dark markings, which is usually called " Burnt" printed. If it is immersed in the electrolytic polishing liquid and taken out, it is clearer and shows a hazy milky white marking. This is caused by overheating of the workpiece and the polishing wheel. Once an industrial aluminum profile occurs, it is often solved by the following methods.
a. Slight alkali corrosion in a dilute alkali solution.
b. Use a mild acid etch, such as a chromic acid-sulfuric acid solution, or a 10% by mass sulfuric acid solution to warm up.
c. A mass fraction of 3% ammonium carbonate and 2% sodium phosphate solution, treated at a temperature of 40-50 °C. The time is 5 min, and the severity can be extended to 10-15 min.
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After being cleaned and dried by the above treatment, it should be re-polished immediately with a fine polishing wheel or a mirror polishing wheel. In order to avoid such situations, the following should be noted during operation.
(1) Select a suitable buffing wheel or polishing wheel. The polishing wheel or the polishing wheel is too hard. Because the grinding amount is too large, it is easy to burn the surface of the workpiece, especially the flat workpiece. If the operation is improper, the undulating surface of the convex and concave will be ground. Conversely, if the polishing wheel is too soft, the abrasive particles in the polishing agent cannot be in direct contact with the workpiece. During polishing, the aluminum scraps that are ground and polished sometimes stick to the rim surface, causing the polishing wheel to slip. Therefore, the operator must master the skill and the appropriate polishing pressure and speed.
(2) Select a suitable polishing agent. The binder in the polishing agent affects the surface characteristics of the workpiece. Industrial aluminum profiles are the same kind of polishing agent. If the binder content is less, the grinding force will be reduced and the polished surface gloss will be high. If you increase the proportion of the adhesive, in most cases, the grinding will be sharper, but the lubrication is good. Excessive grease in the polishing agent tends to make the surface of the workpiece dirty, which is not conducive to the inspection of polishing quality and cleaning. Whether it is a stick-like polishing paste or a liquid polishing agent, it should be done in small amounts but multiple times. After the polishing wheel absorbs enough polishing agent, the amount of grinding is reduced and the light is thrown bright. On the contrary, if the polishing agent is too much, the throwing wheel is easy to slip when it comes into contact with the workpiece, which not only affects the polishing, but also causes waste and increases the cost.
(3) The grinding time of the workpiece and the throwing wheel should be properly mastered. In the simple mechanical manual operation, based on the individual experience of the operator
