Study on milling method of titanium alloy flange
In the milling process of titanium alloy flange, it is necessary to overcome the problems such as easy deformation of flange, high dimensional accuracy, low machining efficiency and high tool consumption cost. In this paper, starting from the material characteristics of this kind of flange, the key points of tool selection, the design of tool path and the process of parameter selection are described. How to improve the machining efficiency of titanium alloy flange, reduce deformation and reduce the possibility of out of tolerance are analyzed The control method of cutting load in process is studied.
Structure introduction and processing requirement of flange
Table of Contents
- 1 Structure introduction and processing requirement of flange
- 2 Cutting performance of materials and selection of cutting tools
- 3 The path design and machining process of the flange milling tool are introduced
- 4 Conclusion
This paper discusses the milling process of titanium alloy flange. There are a set of locating surfaces on both sides of the typical flange. The front end is connected with the engine fairing, and the rear end is connected with the engine fan disc. The holes and lace play a role in fixing and weight reducing. The following is the milling process requirements. The structure of the flange is complex, because most of the structure has a special role, so the dimensional accuracy requirements are high, and the flange processing is difficult. Due to the large machining allowance of this type of flange, the deformation of flange before and after machining must be effectively controlled, and the flange surface quality requirements are relatively strict, so the processing process is relatively complex. This makes the flange processing method and the traditional process method has a big difference. The flange milling process not only needs to complete the strict hole diameter requirements, but also ensures the effective control of processing deformation in the process of removing large surplus. The angular relationship between the holes of the flange is complex, and the position requirement is high. There is a strict position relationship between the holes and the lace. After processing, special processes such as shot peening should be carried out. The above characteristics must be controlled internally to meet the subsequent special requirements It is difficult to process the flange because of the influence of process.
Cutting performance of materials and selection of cutting tools
Introduction of material characteristics
The flange used DMD0777 material equivalent to domestic TC4 alloy, and other metal materials, titanium alloy with a small specific gravity, high hot strength, thermal stability and corrosion resistance is good wait for a characteristic, but at the same time also has a hardness or high temperature titanium alloy material, high hardness and great work hardening, poor heat conductivity, high cutting temperature, easy and great tool of adhesive, chemical activity, the properties of titanium alloy makes it a poor cutting machining of difficult-to-machine materials.
Selection of cutting tools
The selection of cutting tools needs to pay attention to the following aspects:
- (1) From the perspective of tool geometry, the tool back angle can usually be larger to reduce the friction between the flank and the workpiece surface, and the rake angle should also be larger to make the tool sharper, enhance the strength of the cutter head, reduce the processing deformation, reduce the work hardening, and improve the quality of the machined surface.
- (2) From the point strength, heat dissipation capacity, wear resistance, surface quality and processing efficiency, the tool tip radius at the end of the milling cutter can be appropriately increased under the condition of ensuring the rigidity of the clamping and tool system, which allows to reduce the chip thickness under the condition of ensuring the surface quality, thus improving the feed, and strengthening the strength, heat dissipation capacity and wear resistance of the tool tip.
Selection criteria of cutting parameters for titanium alloy machining
The cutting parameters of titanium alloy are close to those of high temperature alloy and some stainless steel materials used in aviation. It is necessary to reduce the cutting temperature, because controlling the cutting heat is the primary means to protect the cutting tool. When cutting titanium alloy, the surface roughness has nothing to do with the cutting line speed, and the influence of cutting depth is very small. Therefore, considering the processing efficiency, the feed rate can be adjusted according to the shape and size of the tool and the arc structure of the end edge, so as to control the stress state of the cutting tool through the thickness and width of the chip, so as to achieve the purpose of machining. In the process of selecting cutting parameters, the cutting load borne by the cutting tool and flange should be considered. The first way to reduce the cutting load is to reduce the cutting force. Light and fast cutting is conducive to reducing the force in the process of flange processing, and then reducing the flange deformation. There are several ways to reduce the cutting load. First of all, small cutting depth and large feed mode can be selected. This method is more common in the process of cutting with end edge. Because this method is easy to remove chip, convenient to cool, and the overall load of the tool is low, so it can achieve the goal of machining and achieve a large material removal rate. Secondly, small cutting width and large feed mode can be selected. In order to reduce the load borne by the tool, the same purpose can be achieved. When both methods can be applied, the first choice is to use the end edge for processing, because the force direction of the tool is more inclined to the axial direction of the tool, and the rigidity is strong. In the case that the end edge wear can not be used, milling with side edge can effectively use all positions of the tool, which is conducive to reducing tool consumption. In the process of flange machining, these two methods have been applied to achieve the balance between machining efficiency and tool cost.
The path design and machining process of the flange milling tool are introduced
General principles of tool path design
The design of tool path has a great influence on flange machining. In the milling process of the titanium alloy flange, several difficult problems of tool path design are overcome. First of all, in order to obtain a larger material removal rate, it is necessary to use the tool with larger feed as much as possible. In the process of large feed application, the change of cutting load at the corner must be avoided. On the one hand, low load cutting in and cutting out are the methods to avoid this problem. On the other hand, cutting load should be adjusted by cutting parameters at small turning angle, that is, using arc cutting method and corner How to reduce the speed. In the process of tool path design, every machining action must be considered, and the cutting load at each moment should be controlled effectively. Only in this way can the tool performance be effectively exerted and the tool loss can be reduced. In the process of milling titanium alloy, the way of down milling is always used. Because of the material properties, the tool wear is large and the surface quality of flange is poor.
Key points of processing
In order to meet the demand of flange batch production and the stability of quality, attention should be paid to several aspects in the process, including:
- (1) The clamping length of cutting tool needs to be strictly regulated, because in the process of material removal with high efficiency, the vibration of flange and cutter is often involved. Although resonance can be avoided by adjusting parameters, the optimal processing conditions should be selected in order to reduce the cost.
- (2) The tool life needs to be tested and counted, because the surface problems such as work hardening often appear in the process of machining titanium alloy flange. This problem is often caused by the tool overstocking the flange surface or chip entering the cutting area, so the blunt cutter can not be used, and the number of flange processed by each tool must be specified clearly.
- (3) The new blade must be used in the finishing process, and it is not allowed to change the blade midway during the finishing process, so as to avoid the unstable influence of the blade size and sharpness on the flange quality.
- (4) For integral cemented carbide tools, it is necessary to check whether the cutting tools are sharp before machining. The tools with serious wear are not allowed to be used.
- (5) During the installation of finishing tools, the tool deflection must be checked. When the tool deflection exceeds 0.02, some characteristics will be out of tolerance.
Due to the reasonable and effective design of the titanium alloy flange processing process, the stability of the residual removal process and the proficient mastery of the operation steps, the high efficiency, high quality and low consumption of the titanium alloy flange processing process are achieved. Through the development of this part, the requirements of the design drawings and relevant documents are finally guaranteed, and the research on the milling technology of the titanium alloy flange of this type is completed successfully.
Source: China Titanium Alloy Flange Manufacurer: www.titaniuminfogroup.com