You may have long been plagued by the problems that mirrors turn black or yellow after edge-grinding, which may cause different degrees of loss in economic and reputation to everyone. The above problem occurred because we did not really understand the causes and take effective measures, so the problem is not fundamentally resolved, and we mistakenly believe that the products from mirror factory or paint factory have problems. In fact that is not the case. Our factory consulted the equipment manufacturers and experts that have years of experience in edge grinding, and comprehensive analyze in the edge-grinding operation process, now we provide some specific methods to avoid the above problem.
First, the selection and use of polishing powder
- Now there are many kinds of polishing powder brands with various functional classifications on the market, you should choose the special grinding mirror polishing powder to use.
- To use PH test paper test the PH of the mixing liquid of polishing powder and water, PH neutral is the best.
- During the edge-grinding process, the temperature of the polishing liquid should be controlled at 17-30 degrees Celsius, preferably not more than 30 degrees. In the process of using should often test the pH, because the glass powder produced by edge grinding may enter the polishing liquid and cause alkaline reaction.
Second, the workers should regularly check. The water spraying angle between the water faucet and grinding wheel should be controlled to spray on the friction surface of grinding wheel and mirror. Otherwise can not reach the cooling effect and to make the silver and aluminum film on the friction surface rapid oxidation at high temperature, then cause black or yellow edge.
Third, it is best to use the resin wheel instead of diamond wheel for the bottom wheel of edge-grinding wheel, and should regularly check the effect of the bottom edge grinding, it must be smooth, so rough edge, burst edge, small gaps and other thorny phenomenons are not allowed. If these phenomenons occur, the contact area of mirror film and water will be greatly increased, if the polishing liquid appears acid-Base properties, it is easy to cause yellow or black edge.
Fourth, the workers should observe carefully when grinding straight edge. The friction direction of chamfering grinding wheel and mirror paint surface is better to be clockwise, because counterclockwise is easy to cause rough edge, burst edge and small gaps to damage the mirror surface, which can not play the role of protective film.
Fifth, the lens after grinding edge should be cleaned timely to avoid residual liquid eroding mirror back paint and affecting the quality of the lens. Each edge grinding machine is best to be equipped with a small or medium sized cleaning machine, when finish grinding a mirror and immediately clean it. It is not only convenient to see the edge grinding quality, but also can be used as a conveyor belt. The price is not expensive, about ten thousand yuan per set. Our factory grinding edge in this way and rarely appear oxidation and black edges phenomenon.