Structure composition of sharp tooth milling cutter
Sharp tooth milling cutters include cylindrical milling cutters, end milling cutters, three face edge milling cutters, etc.
Cylindrical milling cutter is a common tool used to process plane on milling machine. Its geometric angle and parameters include: front angle, rear angle, helix angle, outer diameter, aperture and length, etc.
1. Rake angle: the rake angle of spiral groove milling cutter is divided into normal rake angle and end face rake angle. The normal rake angle is the included angle between the rake face and the base plane in the normal section. The rake angle of the end face is the included angle between the rake face and the base plane in the end section.
2. Back angle: the back angle of the slot milling cutter is divided into normal back angle and end face back angle. The normal rake angle is the included angle between the flank and the cutting plane in the normal section. The rake angle of the end face is the included angle between the flank and the cutting plane in the end profile.
Grinding of sharp tooth milling cutter
（1） Sharpening of rake face
The grinding of the rake face of the straight groove sharp tooth milling cutter is basically the same as that of the straight groove reamer. The rake face of spiral grooved sharp tooth milling cutter is a spiral face, and the conical surface of dished grinding wheel is used for grinding. If the surface grinding with dished wheel is used, interference will occur, which is the same as grinding spiral groove hob.
The grinding of the rake face can be carried out according to the following steps.
(1) Select a suitable dished grinding wheel and install it on the grinding head, and correct the conical surface of the grinding wheel with a diamond pen.
(2) Rotate the grinding head frame, and the rotation angle is smaller than the spiral angle of the milling cutter.
(3) Install the milling cutter on the spindle and put it between the two centers.
(4) Adjust the relative position of the grinding wheel and the milling cutter, introduce the grinding wheel into the tooth slot, and rotate the milling cutter so that its rake surface contacts the conical surface of the grinding wheel.
(5) Start the grinding wheel and start grinding. Hold the milling cutter by hand to make its rake face contact the conical surface of the grinding wheel. While the workbench is feeding longitudinally, the hand milling cutter rotates at a uniform speed.
When grinding to the end of the tooth groove, the force of the hand on the milling cutter should be gradually reduced.
There is no tooth bracket for grinding the rake face of spiral groove sharp tooth milling cutter, and the indexing of the tooth groove is carried out manually.
（2） Grinding of flank
The method of grinding the flank of a straight groove sharp tooth milling cutter with a bowl shaped grinding wheel is basically the same as that of a straight groove reamer. The flank of a straight groove sharp tooth milling cutter is ground with a flat shaped grinding wheel.
(1) Installation and dressing of grinding wheel: install the flat grinding wheel on the grinding head, make the grinding wheel shaft form an angle of 30-45 degrees with the workbench, trim the grinding wheel, trim one edge of its peripheral surface into a conical surface of 2-3mm, and then turn the grinding head frame back to 2-3 degrees. Use the center gauge to adjust the center of the grinding wheel to be the same height as the center of the center, and then raise the center of the grinding wheel according to the size of the back angle of the milling cutter.
(2) Start the grinding wheel and start sharpening: hold the milling cutter by hand, so that a spiral surface of the cutter teeth is closely close to the top of the tooth support plate. While the workbench is feeding longitudinally, hold the milling cutter by hand to make spiral motion with the front cutter surface. After grinding a tooth, pull the milling cutter out of the tooth support and turn it around a slot, and continue to grind the rear cutter surface of another slot, and then grind it slot by slot. After one week of grinding, the grinding wheel shall make transverse feed, and the feed rate shall not be too large, generally 0.02-0.05mm, so as to avoid burning the rear cutter surface.