There are many kinds of metal cutting processes, among which planing and slotting processes are very common in production. In planing and slotting, the quality of cutting tools directly affects the accuracy, surface roughness and production efficiency of the workpiece. Therefore, the correct selection of geometric angle and reasonable grinding of planer and slotter is one of the important contents of planer and slotter technology.
1、 Types of planing and inserting knives
（1） Types and uses of planers
1. According to different processing shapes and uses: generally there are plane planer, partial cutter, cutter, bending cutter, angle planer and forming planer, etc.
(1) Plane planer: used for planing horizontal planes.
(2) Offset cutter: used for planing vertical plane, step surface and outer inclined plane.
(3) Cutter: used for planing rectangular grooves and cutting workpieces.
(4) Bending cutter: used for planing T-shaped grooves, etc.
(5) Angle planer: used for planing angular workpiece, such as dovetail groove and inner inclined plane.
(6) Forming planer: used for planing 1-shaped grooves and special shaped surfaces.
2. By shape and structure: there are left planer and right planer, straight planer and elbow planer, integral planer and combined planer, etc.
(1) Left planer and right planer: they are distinguished according to the left and right positions of the main cutting edge when working. The left and right planers can also be distinguished according to the different directions of the main cutting edges indicated by the thumbs of the left and right hands.
(2) Straight head planer and elbow planer: the planer handle is straight longitudinally, which is called straight head planer; The planer whose head bends backward is called an elbow planer. When the elbow planer is subjected to large cutting resistance, the bending deformation produced by the tool handle bounces back and up, so the tool tip will not bite into the workpiece, which can avoid damaging the planer or biting the machining surface. Therefore, this planer is widely used.
(3) Integral planer and combined planer: the integral planer is made of a cutting tool material; The combined planer is welded or mechanically clamped by the handle and head of different materials.
(4) Indexable cutter: This is a new type of cutter. The multi blade blade is mechanically clamped on the head of the knife body. When in use, grinding is not required. When one cutting edge is blunt, just turn the blade to a certain angle and cut with another cutting edge until all cutting edges are blunt before replacing the blade.
（2） Types and uses of knife inserts
1. According to different processing purposes: there are generally two kinds of sharp knives and cutting knives.
(1) Sharp knife: used for rough inserting or cutting polygon holes.
(2) Cutter: used for fine inserting or cutting rectangular grooves.
2. According to the structural form, it can be divided into integral knife and combined knife.
(1) Integral slotting cutter: its cutter head and handle are integrated, and the cross-sectional area of the cutter bar is small, so the rigidity is poor. It is easy to deform and damage during slotting, and the processing quality is not high.
(2) Combined knife inserting: the knife handle is separated from the knife head, and the knife head is installed on the knife bar. One is that the cutter head is horizontally installed in the handle; The other is installed vertically in the handle. The former has a thick handle and good rigidity, which is suitable for rough insertion; The latter is suitable for slotting inner keyways and square holes with small aperture. The combined knife is easy to use and widely used.
