Combined with high-speed cutter safety standards, by analyzing the finite element model, to meet the security requirements, you can take the following measures:
(1) to reduce the cutter quality and reduce the number of tool components, simplifying the rupture limit of the same diameter cutter body mass test determined the relationship between the different tools and tool component count the number of member contact surface between the tool structure, by comparison, Tool quality more light, the fewer the number of members and member contact surface, the higher the speed limit tool rupture. The study found a knife with a titanium material to reduce the quality of components, can improve tool rupture limit and speed limit. However, due to the sensitivity of titanium to cut and suitable manufacturing cutter body, so some high-speed cutter has been used to manufacture high-strength aluminum cutter body.
In the cutter body structure, should be taken to avoid and reduce stress concentration groove cutter body (including the knife slot, the chip groove, keyway) will cause stress concentration, reducing the strength of the cutter body, and therefore should be avoided through the slot and bottom with sharp corners. At the same time, the structure of the tool body, said in response to the rotary axis, the axis of the center of gravity through the cutter. Blade and knife holder clamping, structural adjustment should be possible to eliminate backlash and require repeated positioning is good. Currently, high-speed cutter has been widely used machine tool spindle connection with the HSK large extent improved the rigidity and repeatability of positioning accuracy tool system, help improve the tool break the speed limit. In addition, high-speed milling machine folder diameter revealed a smaller diameter, knife teeth reduction trends, but also conducive to increase tool strength and stiffness.
(2) Improve tool clamping
Calculation and Experimental Research fracture simulations show that high-speed cutter blade clamping method does not allow the use of a conventional friction clamping blade to use with a central hole, screw clamping, or tool structure specially designed to prevent the blade rejection fly. Knife holder, the clamping force is consistent with the direction of the blade centrifugal best direction, while controlling preload the screws to prevent the screws ahead damaged due to overload. Shank cutter for small diameter, can be used hydraulic collet chuck or thermal expansion and contraction to achieve high precision and high rigidity clamping.
(3) improve the balance of the tool
Improve balancing of the tool to improve the safety of high-speed cutter of great help. Because the tool spindle system unbalance will generate an additional radial load, proportional to the square of its size and speed. Let rotating body mass is m, the amount of eccentricity and centroid rotator center is e, unbalance caused by the centrifugal force of inertia F as follows:
F = emω2 = U (n / 9549) 2
Where: U is the tool system unbalance (g · mm), e for the tool system centroid amount of eccentricity (mm), m is the tool system mass (kg), n is the tool system speed (r / min), ω is the tool system angular velocity (rad / s).
Seen from the above equation, improve tool balancing can significantly reduce the centrifugal force, improve the safety of high-speed tool. Therefore, in accordance with the requirements of the draft standard, high-speed cutting cutter must pass balancing test, and should reach ISO1940-1 specified balance quality grade G4.0.