1. Reduce the quality of non-standard blades, reduce th […]
1. Reduce the quality of non-standard blades, reduce the number of blade components, and simplify blade structure
The relationship between the fracture limit of different blades of the same diameter determined by the test and the mass of the cutter body, the number of cutter members and the number of contact faces of the components. It is found that the lighter the blade quality, the smaller the number of components and the contact surface of the member, the blade The higher the limit speed of the rupture. It has been found that the use of titanium alloy as the tool body material reduces the quality of the component and increases the fracture limit and the limit speed of the blade. .
In the non-standard blade body structure, care should be taken to avoid and reduce stress concentration. The grooves on the tool body (including the knife seat groove, the chip pocket, and the keyway) may cause stress concentration and reduce the strength of the cutter body. Therefore, it should be avoided as much as possible. The groove and the bottom of the groove have sharp corners. At the same time, the structure of the cutter body should be symmetrical to the rotary shaft so that the center of gravity passes through the axis of the milling cutter. The clamping and adjustment structure of the blade and the tool holder should eliminate the play as much as possible, and the repeatability is required. High-speed milling cutters have widely used HSK tool holders to connect with the machine tool spindles, which greatly improves the rigidity and repeat positioning accuracy of the tool system, which is beneficial to the increase of the tool breaking limit speed. In addition, the diameter of the machine-clamped high-speed milling cutter reveals a trend that the diameter becomes smaller and the number of teeth is reduced, which also contributes to the improvement of the strength and rigidity of the tool.
2. Improve the clamping method of non-standard blades
Simulation calculations and fracture test studies have shown that non-standard blade clamping methods do not allow for the usual frictional clamping, using a blade with a central hole, screw clamping, or a specially designed tool structure to prevent the blade from flying. . The clamping force of the blade seat and the blade is preferably in the same direction as the centrifugal force. At the same time, the pre-tightening force of the screw should be controlled to prevent the screw from being damaged in advance due to overload.
3. Improve the dynamic balance of non-standard blades
Improving the dynamic balance of the blade can greatly improve the safety of non-standard blades. Because the amount of unbalance of the blade creates an additional radial load on the spindle system, its magnitude is proportional to the square of the speed.