Analysis of the Fracture of Three-edged Milling Cutter
Introduction
A three-edged milling cutter is an widely used cutting tool for machining processes, which usually consists of three teeth and two flutes. The three teeth can provide a large cutting force and improve the stability of the machining process. Three-edged milling cutter is widely used in boring, milling and other processes in many fields like aerospace industry, automotive industry and medical industry due to its high efficiency and stable performance.
However, during its working process, the three-edged milling cutter is more susceptible to mechanical fractures due to its special structure. Mechanical fractures of milling cutters can cause significant economic losses. Therefore, understanding the fracture mechanism of the three-edged milling cutter is the key to reducing losses. A better understanding of fracture behavior in three-edged milling cutter will allow machinists to better control the cutting parameters and working environment, and provide rational advice on tool selection and cutting process design.
Mechanisms of fracture in three-edged milling cutters
Mechanical fractures are usually presented by chipping, shearing, cracking, breaking and other types of catastrophic failures in three-edged milling cutters. Generally, the following factors are responsible for the fracturing in three-edged milling cutters:
1. Tool fatigue: Tool fatigue often leads to the breakage of three-edged milling cutters. Especially in a hard material cutting process, when the cutting speed is too high or the cutting pressure is too large, the cutting edge will often be excessively exposed to vibration, resulting in a reduction in the fatigue strength of tool material and accelerated wear. When the tool fatigue is serious enough, it may lead to the fracture of the three-edged milling cutters.
2. Thermal cracking: Thermal cracking is another common reason for fracturing in three-edged milling cutters. In the process of machining, large temperature gradients will be formed in the tool material. The temperature of the cutting edge can reach up to 1000 degrees Celsius or more due to increasing cutting speed and feed rate. These high temperatures increase the thermal stress in the tool and may cause micro-cracks, resulting in fracture of the three-edged milling cutter.
3. Residual stress: Residual stress is an internal stress that exists in the metallic material. During the tool manufacturing process, residual stress is introduced into the tool. In the process of working, the residual stress will be further amplified, resulting in the fracture of the three-edged milling cutter.
4. Unbalanced force: Unbalanced force is another factor which can cause the rupture of three-sided milling cutter. The three-edged milling cutter is exposed to large forces while cutting materials. Due to the bevels of the three teeth, the three blades must bear the cutting force in an unbalanced manner. If the force has exceeded the yield strength of the material, the milling cutter may fracture due to the unbalanced force.
Conclusion
In conclusion, the three-edged milling cutter is susceptible to fracture due to its special structure and working conditions. In order to reduce the occurrence of fracture, attention should be paid to the optimization of tool materials, the control of cutting speed and parameters, and the selection of optimal cutting environment. Furthermore, a better understanding of fracture mechanisms and failure modes of three-edged milling cutters will allow machinists to improve cutting performance and reduce the cost of tool replacement and maintenance.
