There are many types of milling cutters, but from the perspective of milling principle, they can be divided into two categories: end milling and circumferential milling, and their typical tools are face milling cutters and cylindrical surface milling cutters. The milling amount includes the following four elements, as shown in Figure 5-4.
(1) Milling speed" (m/min) Milling speed refers to the linear speed when the milling cutter rotates, and the calculation formula is shown in equation (2-1).
(2) Feed There are three ways to express the feed during milling.
1) Feed per revolution f(mm/r) It refers to the distance of the workpiece relative to the milling cutter along the feed direction when the milling cutter moves in each revolution.
2) Feed per tooth f (mm) It refers to the distance of the workpiece relative to the milling cutter along the feed direction when the milling cutter turns the angle of one tooth each time.
3) Feed speed (mm/min) It refers to the distance per minute that the workpiece moves relative to the milling cutter along the feed direction. That is, the feed rate of the milling table.
The relationship between the three feeds: "v=∫n= ∫zm
formula: n -- milling cutter speed, unit r/min or r/s; z-- Number of cutter teeth.
The feed of each tooth is selected according to the strength of the cutting teeth, the thickness of the cutting layer, and the chip capacity. The feed per revolution is closely related to the roughness of the machined surface, and the feed per revolution is selected for fine milling and semi-fine milling. Since the main motion and feed movement of the CNC milling machine are driven separately by two motors in the same service, there is no internal connection between them. Regardless of whether the feed per tooth or the feed per revolution ∫x is selected, the feed rate v must be calculated at the end .
(3) Back supply knife a. (mm) As shown in Figure 5-4, it is the size of the cut layer measured parallel to the direction of the milling cutter axis. In the case of end milling, ", is the depth of the cutting layer; In the case of circumferential milling, ", is the width of the surface to be machined.
(4) Side supply knife a. (mm) It is the size of the cutting layer measured perpendicular to the direction of the cutter axis and the direction of feed. End milling,". is the width of the surface to be processed; And when milling circumferentially, ". is the depth of the cutting layer.
Figure 5-4 The four elements of milling dosage
Circumferential milling b) end milling
