The power control equipment of AC motor is controlled by the frequency mode of motor power supply. In CNC machine tools, the frequency converter is mainly used to control the action of the spindle.
The blade of end mounted structure milling cutter (as shown in FIG. 10) is fixed on the cutter groove with only one screw, which is simple in structure and convenient in rotation. Although there are few tool parts in mechanical parts processing plant, it is difficult to process the cutter body. Generally, it needs five coordinate machining center for machining. Since the blade is clamped by cutting force, the clamping force increases with the increase of cutting force, so the clamping element can be omitted and the chip holding space is increased. Because the blade is installed in tangential direction, the section of cemented carbide in the direction of cutting force is large, so it can be used for large cutting depth and large cutting distance. This kind of milling cutter is suitable for heavy and medium milling.
The angle of milling cutter includes front angle, back angle, main deflection angle, auxiliary deflection angle, edge inclination angle, etc. In order to meet the different processing needs, there are a variety of angle combination types. Among the various angles, the main deflection angle and rake angle are the main ones (the main deflection angle and rake angle of the cutter are generally clearly stated in the product samples of the manufacturer).
Main deflection angle KR
The main deflection angle is the angle between the cutting edge and the cutting plane, as shown in FIG. 11. The main deflection angles of milling cutter are 90 °, 88 °, 75 °, 70 °, 60 ° and 45 ° etc.
Principal deflection angle
The main deflection angle has a great influence on the radial cutting force and cutting depth. The size of radial cutting force directly affects the cutting power and anti vibration performance of cutting tools. The smaller the main deflection angle of the milling cutter is, the smaller the radial cutting force is, the better the vibration resistance is, but the cutting depth is also reduced.
The main deflection angle of 90 ° is selected when milling the plane with shoulder, and CNC machining is not generally used for pure plane machining. This kind of tool has good versatility (not only can process step surface, but also can process plane), so it can be selected in single piece and small batch processing. Because the radial cutting force of this kind of cutting tool is equal to the cutting force, the feed resistance is large, and it is easy to vibrate. When machining the plane with shoulder, the milling cutter with 88 ° main deflection angle can also be selected. Compared with the milling cutter with 90 ° main deflection angle, its cutting performance is improved to some extent.
The main deflection angle of 60 ° to 75 ° is suitable for rough machining of plane milling. Due to the obvious reduction of radial cutting force (especially at 60 degrees), its vibration resistance is greatly improved, and the cutting is smooth and light. Therefore, it should be preferred in plane machining. 75 ° main deflection angle milling cutter is a general-purpose tool with wide application range; 60 ° main deflection angle milling cutter is mainly used for rough milling and semi finishing milling on boring and milling machines and machining centers.
The radial cutting force of this kind of milling cutter with 45 ° main deflection angle is greatly reduced, which is approximately equal to the axial cutting force. The cutting load is distributed on the longer cutting edge, and has good vibration resistance. It is suitable for the machining occasions with longer spindle overhang of boring and milling machine. When machining plane with this kind of cutting tool, the damage rate of blade is low and the durability is high; when machining iron castings, the edge of the workpiece is not easy to break.
Anterior angle γ
The rake angle of milling cutter can be divided into radial rake angle γ F and axial rake angle γ P. the radial rake angle γ f mainly affects the cutting power; the axial rake angle γ P affects the chip formation and the direction of axial force. When γ P is positive, the chip will fly away from the machining surface.
Anterior horn
The common combination forms of front angle are as follows:
The milling cutter with double negative rake angle and double negative rake angle usually adopts square (or rectangular) blade without back angle. The cutter has many cutting edges (generally 8), high strength and good impact resistance, which is suitable for rough machining of cast steel and cast iron. Because the chip shrinkage ratio is large, it needs a large cutting force, so the machine tool has higher power and higher rigidity. Because the forward angle of the shaft is negative, the chip can not flow out automatically. When cutting ductile materials, chip accretion and tool vibration are easy to occur.
It is suggested to use double cutting tool with negative rake angle when machining. When double positive rake angle milling cutter is used to produce chipping edge (i.e. large impact load), the double negative rake angle milling cutter should also be preferred when the machine tool allows.
The milling cutter with double positive rake angle and double positive rake angle adopts the blade with back angle, which has small wedge angle and sharp cutting edge. Because of the small shrinkage ratio of the chip, the cutting power consumed is small, and the chip is discharged in a spiral shape, which is not easy to form a chip accumulation lump. This kind of milling cutter is most suitable for cutting soft materials, stainless steel, heat-resistant steel and other materials. For the machine tools with poor rigidity (such as boring and milling machines with long spindle overhanging), low power and machining welded structural parts, double positive rake angle milling cutters should also be preferred.
Positive and negative rake angle (axial positive rake angle, radial negative rake angle) this kind of milling cutter combines the advantages of double positive rake angle and double negative rake angle milling cutter. The axial positive rake angle is conducive to the formation and discharge of chips; the radial negative rake angle can improve the edge strength and impact resistance. This kind of milling cutter has the advantages of smooth cutting, smooth chip removal and high metal removal rate, which is suitable for large allowance milling. Computer gong processing, Dongguan computer gong processing, high speed computer gong processing, mechanical parts processing, computer gong processing, Walter’s tangential tooth distribution heavy cutting milling cutter f2265 is a milling cutter with axial positive rake angle and radial negative rake angle structure.
The number of milling cutter teeth is large, which can improve the production efficiency. However, due to the limitation of chip holding space, cutter tooth strength, machine tool power and rigidity, the number of teeth of milling cutter with different diameters has corresponding regulations. In order to meet the needs of different users, there are three types of milling cutters with the same diameter: coarse teeth, medium teeth and dense teeth.
Rough tooth milling cutter is suitable for large allowance rough machining of ordinary machine tools and milling of soft materials or large cutting width; when the power of machine tool is small, in order to make cutting stable, coarse tooth milling cutter is often used.
The middle gear milling cutter is a universal series, which makes
About the author