Bearing in the grinding process, its working surface is grinding through a high-speed rotating grinding wheel, grinding if you do not follow the operating instructions and adjust equipment, it appears on the bearing surface flaws, which will then affect the overall quality of the bearings. When bearing in precision grinding, because the rough is very high, working surface of grinding traces are often observed with the naked eye it marks mainly has following several kinds of surface grinding.
　　Manifestations cross traces spiral
　　Traces this mainly due to poor wheel bus straight there is phenomenon of convex, grinding, grinding wheel and the workpiece contact is only partially, after when the workpiece or grinding wheel back and forth movement, the workpiece will again cross screw and can be observed with the naked eye. The helical pitch and speed of the workpiece, the workpiece speed relative to the size of, and parallel to the wheel axis and table rails are not related.
　　(A) the main reason for Helix formation
　　1. bad dressing, corners are not chamfered, trimming the coolant is not used;
　　2. the table Rails too much lubricating oil, table floats;
　　3. the poor accuracy of machine tools;
　　4. grinding too much stress and so on.
　　(B) has reason for Helix formation
　　1.V Rails rigidity is not good, when the grinding wheel offset, edge of the wheel contact with the work surface;
　　2. trim round table when reversing speed instability, accuracy is not high, make the wheel a certain edge trim slightly less;
　　3. rigid workpieces itself poor;
　　4. broken too peeling grains of sand on the iron accumulated in grinding wheel and workpiece surface, dressing well wheel should be rinsed with water or cleaning to clean;
　　5. bad dressing, such as locally raised.
　　Appeared on the surface squamous
　　Reproduction of fish on the surface squamous traces the main reason is because of the grinding wheel cutting blade is not sharp enough, grinding occurs when "eating" phenomenon, when vibration is large. Specific reasons for causing fish scaled marks appear on the workpiece surface is:
　　1. surface of garbage and oil;
　　2. unfinished circle;
　　3. dull wheel. Trimming is not sharp enough;
　　4. Diamond tighten loose, diamond rock or diamond quality is not sharp;
　　5. grinding wheel hardness is not uniform. Face picking
　　Traces of surface reconstruction picking mainly because of the coarse-grain abrasive after shedding, caused between abrasive wheel and clamp the workpiece. Surface grinding is why napping is when:
　　1. the traces left over from when the coarse grinding, fine grinding is not worn away;
　　2. the coarse abrasive with tiny wear particles in coolant filter not clean;
　　3. wear particles in coarse-grain grinding wheels when dressing is easy to fall off;
　　4. validity the toughness or wheel is too soft;
　　5. toughness of abrasive and workpiece material toughness combined with improper
　　Direct waveform marks on the workpiece surface
　　We will mill the vertical workpiece axis cut a cross section and zoom in, you can see its approximate the sine wave. Make it along the axis of the centre line without turning pan, sine waveform is the trajectory around cylinder, also known as polygons. Direct waveform due to relative movement of the workpiece or grinding wheel of grinding wheel on workpiece grinding vibration caused by cyclical changes in pressure of excuse. This vibration is probably forced vibration, may also be the self-excited vibration and therefore direct wave frequency on the workpiece is often more than one. Direct waveform traces of specific causes are:
　　1. the wheel spindle gap too large;
　　2. grinding wheel hardness is too high;
　　3. dull static balancing of grinding wheels or grinding wheels;
　　4. high speed of work piece;
　　5. horizontal Yuan knife is too large;
　　6. grinding wheel spindle bearing wear, clearance is too large, radial runout;
　　7. grinding wheel press agencies or stations "crawling" and so on.
　　Reproduced on the workpiece surface burn marks
　　Workpiece in surface grinding process tends to burn, burn several types, were burned along the wheel processing direction, is dark patches; the second is a line or interrupted lines. Workpiece surfaces were burned during the grinding process, can be summarized in the following reasons:
　　1. the wheel too hard or too fine granularity organization spaced;
　　2. feed rate too much, cutting fluid is in short supply, poor cooling conditions;
　　3. workpiece rotation speed is too low, wheel speed too fast;
　　4. excessive wheel runout, burns due to grinding depth changing;
　　5. dressing is not as bad or when dressing;
　　6. Diamond sharp, dressing well;
　　7. grinding burns when the workpiece too deep, fine grinding is too small, no worn away;
　　8. workpiece clamping force or the suction power is insufficient, under the grinding force and workpiece stops.
　　Workpiece in surface grinding process how do I know if I burn it? You can check it out by periodic acid. The workpiece after pickling, surface when moist, immediately under the broad Visual inspection, a normal surface is uniformly dark gray. Software, renders the clouds of dark black spots and boundary is uncertain if decarbonisation, renders the gray or dark black spots if the grinding crack, crack crack, burn, one wheel machining direction surface dark-colored plaque, the second is to render lines or intermittent lines. As these burn during the grinding process, it must immediately analyze the causes and take effective measures to solve them, to prevent bulk burn.
　　Surface roughness does not meet the requirements
　　Surface roughness of bearing components are standard and process requirements, but in the process of grinding and Superfinishing, for various reasons, often do not meet the specified requirements. Cause the workpiece surface roughness does not meet the requirements of the main reasons are:
　　1. grinding speed is too low, the feed speed too fast, feeding quantity is too large, no feed grinding time is too short;
　　2. the speed of the workpiece or workpiece and wheel axes vibration is too large;
　　3. particle size is too thick or too soft;
　　4. dressing too fast or trimming body clearance is too large;
　　5. the dressing wheel diamond is not sharp or poor quality;
　　6. extra fine oil stone quality is not good, location not installed properly;
　　7. hyper-refined kerosene quality does not meet the requirements;
　　8. finish time is too short;