Guo Wei Industrial Aerospace Lifesaving Equipment Co., Ltd.
Our company is a special tooling design and production department serving the military product system. It mainly designs and manufactures four categories of 66 special tools including molds, fixtures, special measuring tools and auxiliary tools. Due to the wide variety of military parts, our branch not only develops tooling for forming metal materials, but also develops tooling for molding various special materials including plastics, rubber, fiberglass, carbon fiber and plexiglass. At the same time, on the basis of higher processing capacity, it has undertaken a number of high-precision parts processing in aviation, aerospace and medical equipment for many years, and has considerable technical resources and production capacity in the manufacture of aviation parts.
The company's aerospace manufacturing technology and machine tool applications:
At present, the branch has 36 CNC machining equipment, including 9 domestic CNC machining equipment. Including: machining centers, CNC lathes, slow wire cutting machines and electric pulse machine tools. Among them, the proportion of domestically produced machine tools for machining center equipment is the highest. After years of research and practical experience, the functions of these devices have been fully utilized, and at the same time, certain achievements have been made in aerospace manufacturing technology (see Figure 1 and Figure 2).
figure 1
figure 2
(1) Application of machining center equipment:
The machining center equipment is a general-purpose equipment for processing parts of the current branch. It is used to process cylinder parts of automobile engines, gas generator parts for aerospace, various precision parts of aviation and special parts of medical equipment, not only quality is guaranteed, but also production efficiency. Also very high.
(2) The application of CNC turning instead of grinding technology: processing thin-walled precision parts, the material is 30CrMnSiA or titanium alloy, the surface roughness value can reach Ra=0.8 μm; the surface roughness of processed aluminum alloy parts can be better. The hole runout is guaranteed to be 0.01 mm, the bottom end face runout is 0.02 mm, and the outer circle is coaxial with the hole by 0.01 mm. CNC turning instead of grinding greatly increases machining efficiency (see Figure 3).
image 3
(3) The use of slow wire-cutting machine tools: It is mostly used for the processing of precision multi-station progressive die and the processing of special measuring tools. The machining accuracy is ±0.008 mm and the surface roughness can reach Ra=0.8 μm.
(4) Application of electric pulse equipment: The branch company successfully developed a series of precision valve body parts for aviation using electric pulse equipment technology, which solved the processing of precision narrow slot and effectively controlled the profile generated by secondary discharge. For burns, the surface roughness value can reach Ra=0.8 μm.
The angle of the roots can reach R0.04 mm, and the coplanarity of the four holes can be up to 0.005 mm on the same circumferential surface.
The difficulties that branch offices have in aerospace manufacturing and the need for machine tools:
(1) At present, many high-precision aerospace parts tend to be complicated and thin-walled, and many materials such as aluminum alloy and titanium alloy are used. The material removal amount is large during processing, and the control of part deformation is strict, and different types of aviation are required. The structure, size and material of the part are difficult to grasp the accurate deformation law, which is one of the biggest variables in CNC machining. Therefore, we hope that the domestically produced CNC equipment can be equipped with a common fixture that uses hydraulic or vacuum chuck positioning and clamping. The main advantage of this type of fixture is that the clamping force is adjustable, and the clamping force and the overall force of the parts are achieved. The quality of thin-walled parts is well guaranteed; another significant advantage is that the clamping force remains constant during positioning and clamping, ensuring consistent processing quality in the same process.
(2) High-precision aerospace parts have strict requirements on flash burrs. All edges of the whole part are blunt as required (except for special requirements). CNC machining cannot fully meet the blunt requirements in production, for example: complex convex The small rounded corners of the table, the inner hole opening and the stepped hole chamfering, etc., the chamfering processing of these small parts is currently manually repaired by the fitter, the workload is quite large, and the work efficiency is low, which is one of the bottlenecks of the processed parts. It is hoped that the CNC equipment manufactured in China can be developed from small places, and solve the practical problems of users from the aspects of processing, tooling and program development.
The gap between machine tools at home and abroad:
The most obvious disadvantage of domestic machine tools in use is the poor rigidity. The same amount of feed and speed, the vibration of the parts processed by domestic machine tools is obvious. In order to ensure the quality, the feed rate during processing cannot be large, so the processing efficiency is lower than that of foreign equipment. In addition, there are many small problems, such as oil leakage and small electrical component failures. These small problems often restrict the development of state-owned machine tools.
In terms of tools, the obvious difference between domestically produced tools and foreign countries is that domestic tools have a short service life. Similarly, the hole in the valve body part can be machined with 10 to 15 holes, and the imported tool can process more than 30 holes. Especially when machining small holes, the breaking rate of domestic tools will be higher. Through analysis, we believe that domestically produced tools are not only required for processing and coating technology, but also for material problems.
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