The cutting edge on the surface of the round shank of the tungsten steel milling cutter is the primary cutting edge, and the cutting edge on the end surface does not pass through the center and is the secondary cutting edge. The workpiece is not suitable for axial feed movement. Before sharpening, the grinding wheel should be inspected. In case of run-out, irregular cylindrical surface, excessive fillet, etc., it must be trimmed. Generally, the cylindrical surface of the grinding wheel can be dressed with a wheel dresser (diamond dresser, gear dresser, etc.), or a used grinding wheel with relatively large abrasive grain hardness can be used for dressing. If the side surface of the grinding wheel is uneven, the grinding wheel can be replaced.
Tungsten Steel Milling Cutter End Face Grinding Technology
Regardless of the number of blades in a tungsten steel milling cutter, the end face of the blade must first be ground flat perpendicular to the axis. This is key to ensuring that the highest point of the blade is on the same plane. The methods for grinding the blade end and checking the verticality of the cutter axis are as follows:
(1) Visual inspection. Using a flat plate, place the tungsten steel cutter blade down on the flat plate and observe the left and right tilt angles. Then rotate the cutter 180° and observe its left and right tilt angle. In the same direction, if the inclination angles observed twice are different, grinding is necessary until the inclination angles observed twice in the same direction are the same. Then rotate the cutter 90°, repeat the above action and check the other direction.
(2) Use a square ruler to correct. Calibrate with a 90° square ruler on a flat plate. Place the cutter and square ruler flat and observe whether there is a gap between the cutter and the square ruler or whether the gap is uniform. Then judge the verticality of the milling. cutter according to the gap and correct the cutter. The knife is sharp.
(3) Self-correction. Fix the tungsten steel cutter on the chuck of the drill or milling machine, place a scrap grinding wheel underneath, select the appropriate rotation speed, turn on the machine tool, then move the cutter down, grind on the grinding wheel, and grind according to the grinding situation of the end face.
(4) Place the heavily chipped tungsten steel cutter on the cutting machine. After adjustment, cut the cutter section in one go.
(5) Grind the tool on the cutter and clamp it with a three-jaw or tapered sleeve. After adjustment, use a grinding wheel to grind the end face of the cutter until it meets the requirements.
Cross-flute technology for tungsten steel cutters
If there is no circular groove on the front of the end face of the four-blade tungsten steel cutter, you need to use the grinding wheel thread or use a grinding wheel cutting machine to reopen the transverse groove in the direction of the transverse spiral groove of the cutter, with a depth of about 1-2mm (too deep is easy to crack, too shallow is easy to grind the secondary back corner). When grooving, make sure that the side of the grinding wheel does not touch the other cutting edge below (Note: This cross groove has a chip evacuation function. If it is not open, the angle of inclination of the recessed edge in the middle should be increased).
Tungsten Steel Milling Cutter End Face Point Sharpening Technology
(1) When sharpening each blade surface separately, use the tip of each blade as a reference and keep the tip of the blade as a principle, then grind the cutting angle (no need to grind if it is not is no chipping), clearance angle and secondary clearance angle (if a large cutting volume requires better strength, it is recommended to increase the edge corner angle) and tilt angle of the edge in front of the tool sharpening.
(2) Relevant angle selections are draft angle 6° to 8° (secondary draft angle 30° to 45°) and edge tilt angle 1° to 3°. The choice of draft angle depends on the hardness of the part. The greater the hardness of the material, the smaller the angle. The principle of selecting the blade tilt angle is that the four blades should be concave towards the middle and. the middle of the blade should not be convex, otherwise the milled plane will definitely be uneven, and the more concave the middle of the blade, the better. In fact, the four blades are concave towards the middle. the better the roughness accuracy. At this point, the deeper the processing depth (e.g. greater than 2mm but within the allowable range), the better the roughness accuracy, as the entire cutting edge will participate in the cutting and the resulting surface quality will be best.
(3) After sharpening, place the tungsten steel cutter on a platform. If the axis is vertical, all the tips of the blade can be aligned and the angle of deviation of the blade can be evenly centered, so that it can meet. the requirements. At this time, you can also use a 90° square ruler on a flat plate to correct it. After laying it flat, observe whether there is a gap or whether the gap is uniform between the cutter and the square ruler. Generally, look at the two relatively high feet first (the two feet that touch the bottom first). If they are not vertical, grind the taller legs until the two opposite legs are the same height (i.e. vertical at that point). feet If there is a difference in height between the two opposite feet, the cutter will oscillate. At this time, lower both upper feet at the same time. Likewise, rotate the cutter 90° to observe the verticality of the other two opposite legs, and finally make all four legs touch the bottom at the same time and make the cutter vertical. Milling cutter after sharpening.
In manual sharpening, it is not easy to grasp the height and angle of the blade. This varies from person to person when training. Just be careful to sharpen the back angle a little, but it should be concave in the middle. , even if the cutting edge is uneven, as long as the cutting edge simply holds the tip at the highest point, which can also ensure that the sharpened tool can be milled normally. In addition, if it is not necessary to clean the internal cavity, you can also grind the chamfer more than 0.2mm at the tool tip to increase the strength of the tool tip .
Sharpening technology of the main edge of the tungsten steel cutter (i.e. the side edge)
If the main edge of the tungsten steel cutter is worn, it should be ground along the spiral line on the grinding wheel (smaller grinding wheel diameter is better) (it is difficult for beginners to grind it well) . However, there is usually a taper after grinding. The smaller the taper, the higher the operating level.
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