Relieving milling cutters are mostly formed milling cutters. The relieving milling cutter with high precision can shovel the tooth back before quenching and grind the tooth back after quenching. The general precision relieving milling cutter does not shovel and grind the tooth back after quenching. The wear of relieving milling cutter is generally on the back face, but only the front face is sharpened, and the back face is not sharpened, which is the same as that of gear hob.
1、 Constitution of relieving milling cutter
Relief milling cutters include gear milling cutters, thread milling cutters, convex (concave) semicircular milling cutters, etc.
The back of the relieving milling cutter is Archimedes spiral, and its blade shape and back corner are formed by relieving or grinding on the relieving lathe.
After the teeth of the relieving milling cutter are worn, only the rake face is sharpened. After grinding, the axial profile of the cutter teeth remains unchanged, and the change of the back angle is very small.
2、 Grinding of relieving milling cutter
1. Sharpen on the hob sharpening machine
Install one or more relieving milling cutters (mostly new blade grinding) of the same specification on the spindle, and align the rake face of each milling cutter before locking; After locking, install the spindle and milling cutter between the two centers on the hob grinding machine tool. The grinding method is the same as that of gear hob. The hob grinding machine has high efficiency, high indexing accuracy and good grinding quality.
2. Sharpening on universal tool grinder
When grinding the shovel tooth milling cutter on the universal tool grinder, if the conical surface of the grinding wheel is used for grinding, the grinding head needs to be deflected by an angle when trimming the grinding wheel, and then move the workbench, trim the grinding wheel out of the conical surface with the grinding wheel dresser, and then restore the grinding head to its original position. If the plane of the grinding wheel is used for grinding, the working surface of the grinding wheel should be trimmed into an inward inclined shape to reduce the contact area between the grinding wheel and the rake face of the milled cutter. When grinding milling cutter, the indexing is completed by the indexing plate installed on the same spindle as the milled cutter.
3、 Measurement of milling cutter grinding
Multi edge angle ruler can be used to measure the front angle and back angle of straight groove sharp tooth milling cutter, and the measurement method is the same as that of reamer. Spiral sharp tooth milling cutter generally gives the normal rake angle and end face back angle in the drawing, so the normal rake angle should be converted into end face first. Measuring method of rake angle and radial runout of relieving milling cutter: measure the rake angle according to straight teeth.
The measuring method of the rake angle of the relief milling cutter is the same as that of the straight groove sharp tooth milling cutter. The milling cutter can also be installed on the measuring mandrel and pushed between the two centers of the deflection tester. If the rake angle of the milling cutter is equal to zero degrees, the rake face of the milling cutter should pass through the center of the milling cutter, that is, through the center line of the two centers of the deflection tester.