| The integral impeller is the core component of the centrifugal compressor and the mold is widely used in the processing of industrial products,both of which have typical cavity structures in structure.When processing the cavity,large amount of material is removed with the low processing efficiency.The plunge milling process can significantly improve the cavity processing efficiency,but when performing high-efficiency plunge milling,especially the half width and high-efficiency plunge milling,there is a significant impact at the cut-in position of down milling and cut-out position of up milling which can lead to a significant reduction in the service life of milling tools.Aiming at this problem,this paper studies the factors and laws that affect the cutting impact force and analyzes the failure process of plunge milling tools and designs plunge milling tools based on the principle of wave chip separation.The main research contents are as follows:Firstly,the cutting characteristics of plunge milling and the main factors affecting the cutting impact are analyzed,and then the plunge milling experiment is designed and carried out accordingly.A single variable method is used to cut 40 Cr material with a single-edge plunge milling tool,and then the plunge cutting force is measured to analyze the influence of cutting parameters and tool geometry parameters on cutting impact.The study found that the plunge milling impact is the largest when the radial depth of cutting is equal to half width of the radius of the tool,and plunge milling impact is the smallest when the radial depth of cutting is equal to full width of the radius of the tool.The cutting force increases with the increase of cutting speed,feed rate and plunge step,but the influence degree is different that he feed rate has the greatest influence,the slotting step is the second,and the cutting speed has the smallest influence.The cutting impact is the smallest when the tool’s main declination angle is 93° to 96° and the blade inclination angle is about 5°.Secondly,the tool’s failure process and tool life when cutting 40 Cr alloy steel and FV520 B stainless steel wire by different plunge milling techniques are studied.Through experiments,it is found that the failure of plunge milling tool is the result of the combined action of wear and damage.The failure process can be divided into three stages: early stage,middle stage and late stage,in which the early and middle stages are mainly worn,and the late stage is mainly damaged.When plunge milling 40 Cr alloy steel,the cutting temperature is the main factor that affects the tool life and he tool life is the shortest when the full width plunge milling is used,so that the up milling method should be preferred when half width plunge milling.When plunge milling FV520 B stainless steel,the problem of impact is the main factor that affects the tool life and the tool life of the half width plunge milling is shorter than that of the full width plunge milling.At the same time,the up milling method should be avoided when the half width plunge milling FV520 B.Finally,the cutting characteristics of the wave edge plunge milling tool are analyzed and it is found that the wave edge can increase the cutting thickness and the cutting width in the plunge milling,which are beneficial to reduce cutting deformation,cutting force and cutting temperature.Wave edge plunge milling tool was designed using the three-blade chip splitting scheme and the cutting experiments were carried out to compare the cutting performance of wave edge plunge milling tool,chip slot plunge milling tool and straight edge plunge milling tool.During the cutting process,the cutting force of wave edge milling tool is significantly lower than the cutting force of chip slot plunge milling tool and straight edge plunge milling tool,which shows that the wave cutting edge can effectively reduce plunge milling cutting force. |
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