Three things to do before grinding the grinding wheel
Special attention should be paid to installing the grinding wheel on the grinder. Because the grinding wheel works under high speed rotation conditions, it should be carefully inspected before use and no cracks are allowed. The installation must be solid, and should be adjusted by static balance to avoid causing personal and quality accidents.
1. Inspection of Grinding Wheel
Grinding wheel inner hole and grinding wheel shaft or flange outside the circle, can not be too tight, or grinding when the expansion of heat, easy to expand the grinding wheel, can not be too loose, or grinding wheel prone to eccentric, lose balance, resulting in vibration. General fit Clearance is 0.1.8mm, high speed grinding wheel clearance to be smaller. When using the flange disk clamping wheel, two flange diameter should be equal, the external diameter should not be less than 1/3 of the diameter of the wheel. In the flange and grinding wheel face between the application of thick cardboard or oil-resistant rubber, such as liner, so that the pressure evenly distributed, the nut of the tightening force can not be too large, or the grinding wheel will rupture. Note that the rotation of the fastening thread should be opposite to that of the grinding wheel, that is, when the wheel rotates counterclockwise, the screw thread is used, so that the grinding wheel will rotate the nut more tightly under the action of grinding force.
2. Wheel Balance
The general diameter of the wheel larger than 125mm should be balanced, so that the center of gravity of the wheel and its rotating axis coincide.
Uneven grinding wheel In the high-speed rotation will produce vibration, color ring processing quality and machine accuracy, serious damage and grinding wheel fragmentation. The main cause of imbalance is the uneven density of the grinding wheel, asymmetrical geometric shape and eccentric installation. Therefore, before the installation of the wheel should be balanced, the balance of the wheel is static balance and dynamic balance. In one condition, only static balance is needed, but the dynamic balance must be carried out when the high speed mushroom is cut (the speed is greater than 50m S) and the high degree of structure grinding. The following diagram is a static balance device for grinding wheel. Balance the wheel on the balance of the spindle, and then put the good shaft of the wheel flat on the balance of the balancing guide, the wheel will swing back and forth until the swing stops. A balanced wheel can be stationary at any position.
If the wheel is unbalanced, the heavier part always goes below. The position of the movable balance block is then balanced. The balanced grinding wheel should be inspected before being installed to the spindle of the machine tool, and the cracked grinding wheel is absolutely forbidden. Between the grinding wheel and the flange should be 0. 5-1 the elastic pad of the book: the diameter of the two flanges must be equal, the size of which is generally half of the diameter of the grinding wheel
The method of balancing the wheel: A few balance blocks are loaded in the annular groove of the flange of the grinding wheel, and the center of gravity of the wheel is coincident with its rotating axis by adjusting the position of the balance block.
3. Dressing of Grinding wheel
During the grinding process, the abrasive grains of the grinding wheel are gradually grinding round and dull under the action of friction and extrusion, or when grinding the ductile material, the debris is often inserted in the pores of the grinding wheel surface, which causes the grinding wheel to jam, and finally makes the grinding wheel lose its cutting capacity. At this time, the grinding wheel and the workpiece will produce slippage between the phenomenon, and may cause vibration and noise, so that the grinding efficiency decreased, the surface roughness of the poor. At the same time, due to the increase of grinding force and grinding heat, the workpiece deformation and the grinding precision will be affected, and the surface of grinding can be burnt and small crack. In addition, due to uneven grinding wheel hardness and different working conditions, so that the grinding wheel work surface wear is uneven, the various parts of the abrasive particles fall off, resulting in grinding wheel loss of shape accuracy, affecting the workpiece surface shape accuracy and roughness. Where the above situation, the grinding wheel must be trimmed to cut off the surface of a layer of abrasive, so that the surface of the grinding wheel to reveal the sharp grinding particles, in order to restore the grinding wheel cutting capacity and accuracy.