In machining, it is a common process to grind the end face of opposite milling cutter. When grinding, first observe whether the end face of the blade is perpendicular to the axis of the milling cutter. Only in this way can we ensure that the highest point of the blade can be in the same plane. In addition, there are also some precautions in the grinding technology that people need to know from the operators of machining.
Correction of perpendicularity of blade end face
The first method is visual inspection, which can be observed with the help of a flat plate. Place the edge of the end milling cutter on the flat plate and observe the inclination angle of the left and right sides of the milling cutter. Next, rotate the milling cutter 180 degrees, and then observe the tilt angle on the left and right sides. If the tilt angle observed before and after rotation is different in the same direction, it means that the verticality is not good enough and needs sharpening. If the angle is the same, turn the milling cutter 90 degrees and repeat the above operation. Until it is confirmed that the inclination angle of each angle of the milling cutter is the same.
The second method is to use a square, which is also operated on a flat plate. After placing the milling cutter and a square on the flat plate, observe whether there is a gap or whether the gap is uniform between the milling cutter and the square, so as to judge whether the perpendicularity of the milling cutter is good.
The third method is self calibration, which is determined by the milling effect of the milling cutter on a waste grinding wheel. Clamp the end milling cutter on the chuck of the milling machine, put a waste grinding wheel under it, let the milling cutter mill the grinding wheel at an appropriate speed, and grind it according to the milling condition of the end face.
Technical points of end grinding
When grinding each cutting edge separately, it must take the tip of each edge as the benchmark and keep the tip as the principle. In case of edge collapse, the front corner must be polished. If there is no edge collapse, it can not be polished. If you want to perform the machining task of large cutting amount, you need to have high strength of the tool. At this time, you should grind the wedge angle of the blade in front of the tool to increase its angle.
The choice of the back corner should be determined according to the hardness of the workpiece. If the material hardness is larger, the back corner should be smaller, otherwise the material hardness is smaller, the back corner should be larger; When selecting the angle of edge inclination, it is necessary to ensure that all four edges are concave to the middle. The flatter the angle is, the better the roughness and accuracy during cutting. Moreover, within the allowable range of machining depth, the deeper the depth is, the better the roughness and accuracy will be, because the whole cutting edge is involved in the cutting result. Generally, the selection range of rear angle is 6 to 8 degrees, the secondary rear angle is 30 to 45 degrees, and the blade inclination is 1 to 3 degrees.
After the grinding is completed, check it with the method introduced in the correction of the perpendicularity of the blade end face. If the requirements are met, the grinding effect is ideal. If the effect is not achieved, you need to continue sharpening. When correcting with a square and observing the gap between the milling cutter and the square, there is a certain order to follow. Generally, observe two relatively high feet first. If they are not vertical, grind the higher feet first, so that the two opposite feet are the same height. At this time, there is a height difference between these two feet and other feet, and the milling cutter will swing. At this time, grind the other feet low. Finally, all feet touch the bottom at the same time and make the milling cutter vertical.
In manual grinding, it is not easy to grasp the height of the blade and the inclination angle of each angle. It is necessary to pay attention to grinding a little back angle. If the top edge is not flat, just let the tip be the highest. In addition, if it is not the case of machining the inclination of the inner cavity, you can also grind the chamfer greater than 0.2mm at the tip to increase the strength of the tip.