Research On Technics Of High-speed Milling

1. IntroductionAs a bran-new technology, high-speed milling is known to be with the characters as high cutting speed, high feeding rate, high machining precision and excellent surface quality. high-speed milling adopts high rotating speed and high feeding rate, which is very different from the old machining methods. And it has been introduced into aerospace, auto-manufacturing industries, etc. Different factors are related to high-speed milling technology, such as high-speed milling machine tool system, high-speed milling control system, high-speed milling technics system and so on. Because of overseas restriction to china on high-speed machining equipments, the precise and over-precise machining technology of china has been dropped behind. Based on the FIDIA high-speed milling center, this paper mainly concentrates on the research of high-speed milling technics. The optimized parameters will be used to make effective guidance to actual production.2. Analysis and research on affecting factorsModern optimization techniques includes three aspects, namely, optimization control, optimization design and optimization experiments. Among which optimization experiments is an optimization method under the guidance of optimization ideology. Multi-factor orthogonal testing method, which is important in optimization experiments design, will explore the relationship among factors in the milling process. The influences on experiment result can be easily educed with this method. Therefore, Multi-factor orthogonal testing method was chosen to confirm the affecting factors of high-speed milling.This paper illustrated the factors in high-speed milling, they are tool parameters, cooling & lubricating way, rotating speed, feeding rate, cutting depth and radial feedrate. The influence size, influence way and mechanism of those factors to the surface quality are different from each other. Here Multi-factor orthogonal testing method will be employed to make analyses. According to ourneeds, the experiment was designed as L9 (3 4) orthogonal testing method with four factors.3. Experimental study on influence of parametersLayer of cutting is formed in cutting process because of the tool effect, at the same time, we have the machined surface. Two methods can be used to research on this process, Theoretical model and experiment model. However, the present high-speed cutting theory only research on several tools and materials and they are not enough for building theoretical model. So the milling experiments will be employed to analyze the influence of parameters. Actually, experimental research is much more direct than theoretical research.The chosen materials are duralumin alloy, 45# steel and stainless steel. And the research concentrated on surface roughness influenced by milling parameters (they are rotating speed, feeding rate, cutting depth and radial federate). Milling parameters were optimized in the research to guide the actual production.4. Experimental study on machining obliquityUnder normal vertical milling condition the cutting speed will be zero at the center of the cutting blade (knifepoint), which makes the accommodation space for scrap will be small. The tool will scrape over the workpiece more than cutting through. And the surface quality will not be good. What's more, wear and tear will happen in a short time under this milling condition. Therefore, a obliquity is needed to avoid the cutting from knifepoint. In order to carry out the experiment conveniently, the workpiece was designed as what fig.1 shows. The deflexion angle is 5 degrees between two nearby faces, which matches the fact that the tool will locate each 5 degrees and the total range -25°～25°.Optimized obliquity to chosen material and tool was educed according to the experiment, which helped to avoid the influence from zero cutting speed of knifepoint to surface quality and tool life. That's important especially in plane machining. Besides, this paper pointed out the program principle basing on obliquity in high-speed machining.5. ConclusionThree kinds of material, namely LC4 duralumin alloy, 45# steel and 1Cr18Ni9Ti stainless steel, were used to research on the influence of milling parameters (including tool parameters, rotating speed, feeding rate, cutting depth, radial federate and obliquity) to surface roughness, the eigenvalue. The conclusions are as following:Formation mechanism of surface roughness in high-speed milling was studied and analyzed with Multi-factor orthogonal testing method. With the result we fixed out the influence situation of tool parameters, rotating speed, feeding rate, cutting depth, radial federate to surface roughness.In order to research on parameters deeper, this paper designed experiments according to their own characteristic, and sum up the influence rules of rotating speed, feeding rate, cutting depth and radial feedrate to surface roughness. All these data is valuable to actual production and latter experiments.Test piece was designed to carry out multiple goals. So did the obliquity experiment. These efforts provided us ways on how to improve surface quality and tool life. Cutting strategy was pointed out considering the obliquity.The research outcome is of great effect and guidance when used in actual production. So we can say that it's very important to do research on technics of high-speed milling.