High Speed Milling Application in Mould Machining
Abstract
High speed milling is a machining process in which a cutting tool performs a batch of machining operations at a high speed, mostly in milling of complex mould shapes such as automotive, aircraft and microelectronic parts. Compared with traditional milling, the cutting speed and force of high speed milling are greater, the cutting tool vibration is larger, and the cutting temperature is slightly higher. This paper introduces the application of high speed milling in mould milling and the basic requirements for the selection of high speed cutting tools and machining parameters.
1 Introduction
High speed milling (HSM) is a machining process in which the cutting tool has higher cutting speeds and greater cutting forces than traditional milling processes, making it suitable for machining some complex mould shapes. High speed milling includes both heavy-duty and standard high speed milling. Heavy-duty high speed milling is carried out on powerful, special purpose machines with spindle power greater than 30 kW. This paper focuses on standard high-speed milling, carried out on CNC machining centers with spindle powers between 7-25 kW. This form of high-speed machining is ideal for mold making, as it is applied with no additional technology and the existing machine resources can be adapted for operation for high-speed machining.
2 Tool Selection and Parameter Setting
The selection of cutting tool materials, coating and geometry is a significant factor that can improve the surface finish and tool life in mould machining. In mould machining, the cutting tools usually used include tungsten carbide end mills, indexable end mills, tungsten carbide drills and tungsten carbide reamers. The barrel type tungsten carbide end mills are best used for roughing and finishing of mould surfaces, while the flat or indexable end mills are suitable for finishing of fine surfaces and threading operations.
For high speed milling of moulds, it is important to pay attention to the parameters such as cutting speed, feed, depth of cut, etc. At the same cutting speed, the feed used should be as large as possible to reduce the number of passes and provide good surface finish. When setting the depth of cut, it should not be too large. Otherwise, the force exerted on the cutting tool will increase, and the cutting resistance will reduce the number of passes and lead to poor surface finish. The spindle speed should be as high as possible considering the power of the CNC machine tool.
3 Conclusion
High speed milling is a machining process which produces less noise, less vibration, and higher cutting speeds, making it ideal for mould machining. The selection of the appropriate cutting tool materials and coating is important for the performance of the high speed milling process. In addition, setting the appropriate machining parameters such as cutting speed, feed, and depth of cut is also important in ensuring good surface finish and tool life.
