Before grinding, it is necessary to inspect the grinding wheel. If the grinding wheel is found to run out, the cylindrical surface is irregular, and the fillet is too large, it is necessary to repair it. Generally, the cylindrical surface of grinding wheel can be trimmed by wheel corrector (diamond dresser, gear wheel dresser, etc.), and the worn-out grinding wheel with relatively high hardness can also be used for dressing. If the side plane of the grinding wheel is still uneven, the grinding wheel can be replaced.
End face grinding technology of end mill:
Technology of grinding end face of end mill
No matter how many edge end mills, first of all, the end face of the cutting edge should be vertical to the axis, which is to ensure that the cutting edge can be in the same plane with respect to the high point. To correct the perpendicularity of the end face of the cutter with respect to the axis of the milling cutter is as follows.
① Visual inspection. With the help of a flat plate, the edge of the end mill can be lowered on the flat plate to watch the skew angle controlled. Then turn the milling cutter 180 ° and watch its control skew angle. If the skew angle difference is observed twice on the same target, it needs to be polished until the same skew angle is observed twice on the same target. Then turn the milling cutter 90 ° and repeat the above actions.
② Correct with a square. Correct with a 90 ° right angle square on a flat plate. After leveling the milling cutter and square, check whether there is a gap between the milling cutter and the square or whether the clearance is average. Thus, it is possible to infer the perpendicularity of the milling cutter, as shown in Fig. 1.
③ Self correction. Clamp the end mill on the chuck of drilling machine or milling machine, place a waste grinding wheel under it, select appropriate speed to start the machine tool, and then move down the milling cutter to grind on the grinding wheel, and grind according to the end face grinding condition.
Technology of cutting cross chip removal groove for end mill
If there is no circular groove in the front of the end eye of the four blade end mill, it is necessary to use the fillet of the grinding wheel to re open the cross groove along the spiral groove target of the milling cutter, and control the depth of 1-2mm (if it is too deep, it is easy to crack, if it is too shallow, it is not easy to grind out the rear corner of the pair). When slotting, pay attention to the side of the grinding wheel to avoid suffering from another blade under it (Note: this cross groove has the function of chip removal. If it does not open, the inclination angle of the edge concave into the middle should be increased).
Edge grinding technology of end milling cutter cutting edge
① When grinding each edge, take the tip of each blade as the benchmark and keep the edge tip as the principle. Grind the front angle (if there is no chipping edge, it is better not to grind), the back angle, the auxiliary back angle (if the cutting amount is large, it is suggested to increase the wedge angle in front of the grinding tool) and the edge inclination angle.
② The selection of the relative angle is 6 ° to 8 ° for the back angle and 1 ° to 3 ° for the edge angle. ? the selection of the back angle depends on the hardness of the workpiece. If the hardness of the raw material is large, the angle will be smaller. The selection principle of the angle of the edge angle is that all four edges must be concave into the middle. The smoother the angle, the better the roughness accuracy. At this time, the deeper the machining depth is (if it is greater than 2 mm, but it should be within the allowable limit), the roughness accuracy will be better, because the whole cutting edge is added with the cutting effect.
③ After grinding, the milling cutter is erected on a platform. If the axis is vertical, all the edge points can be even, and the deviation angle of the cutting edge can be even, so it can meet the requirements.
At this time, it is also advisable to use a 90 ° square on a flat plate for correction. After leveling, check whether there is a gap between the milling cutter and the square or whether the clearance is average. Usually watch two relatively high feet first (the two feet touching the bottom first). If they are not vertical, grind the higher feet so that the two opposite feet are the same height (i.e. vertical). At this time, there is a height difference between these two feet and the other two opposite feet, and the milling cutter will swing. At this point, grind the two higher feet down at the same time. Similarly, turn the milling cutter 90 ° to observe the perpendicularity of the other two opposite feet, and finally make the four feet touch the bottom at the same time and make the milling cutter vertical. Milling cutter after grinding.
In manual sharpening, it is not easy to master the height and angle of the blade. In practice, it is necessary to vary from person to person. As long as you pay attention to grinding out a little back angle, you may as well. In addition, if it is not the condition of machining inner cavity angle cleaning, you may as well grind the chamfering greater than 0.2mm at the tool tip to increase the strength of the tool tip.
Grinding technology of main edge (side edge) of end mill
If the main edge of the end mill is worn, it is necessary to grind it along the spiral line on the grinding wheel (the diameter of the grinding wheel is smaller, better). However, there is usually taper after grinding. The smaller the taper, the higher the control level.
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