When grinding the workpiece, we often find that there will be burns on the surface of the workpiece, which has a certain relationship with the high-speed operation of the CBN grinding wheel. The main types of workpiece burns are linear or discontinuous. There are two types of black spot burns along the grinding direction of the grinding wheel.
So, what causes the workpiece to burn in the process of grinding with high-speed CBN grinding wheel?
1. High hardness or fine particle size of CBN grinding wheel;
2. The cutting fluid supply is not sufficient, the feed amount is too large, and the heat dissipation conditions are not good;
3. CBN grinding wheel dressing is not carried out in time or the quality of dressing is not good;
4. Large vibration of the grinding wheel, resulting in burns due to constant changes in the grinding depth of the workpiece;
5. The card is not firm enough, and the workpiece stops when grinding;
6. The workpiece is burned deeply during rough grinding, and the fine grinding is small, without grinding away;
So how can we tell if a piece is burned?
Very simple, by regular pickling method can be checked out. When the pickling surface of the workpiece is wet, we must quickly carry out a visual inspection under the fluorescent lamp. Normal workpieces without burns are uniformly dark gray. If the crack is cracking, it is grinding crack. If there are gray or dark spots, it is a decarbonization phenomenon; If there are dark cloud spots, and the perimeter is not uniform, it is a soft spot; If the workpiece surface along the grinding wheel grinding direction appears dark spots, continuous lines or discontinuous lines, it is a burn phenomenon.
When grinding the workpiece, if there is a burn, we must find out the cause in time and take limited measures to solve it, only in this way can we grind out a standard quality product.