1、1 附录 Fork Shaft Lugs fixture design Shell group processing according to the results of the machine and the group chosen type design group clamps, group clamps Realize that the group process, favorable to reasonable design, if no group clamps or design group clamps, convenient adjustment group proces
2、sing can realize smoothly. The machine tools fixture priority is to ensure machining accuracy, especially that of the machining process and positioning surface and processed surface between the position precision. After using this fixture mainly rely on precision tools and fixtures to ensure no long
3、er rely on workers, the technical level. Second is to improve labor productivity, reduce cost, use fixture after is crossed, can reduce the auxiliary time, and easy to implement and multistage process. In modern times, is widely used in the machine tools fixture etc mobile pneumatic, hydraulic clamp
4、ing device, can make the assistant time do step. In the group technology group clamps are under the guidance of the principle, process and design for the implementation of the group, and special fixture Compared with the design group clamps, not for a certain parts of a process, but a group of some
5、parts, Which group clamps to adapt to all parts of the group parts in a process of processing. Design of the key and difficult. When the workpiece in machine processing, the first to make workpiece in machine or a fixture in the correct position, it is the location, to prevent the process of cutting
6、 force or other forces destroyed the correct position, still must be fastened clamping workpiece, this is the clamping workpiece position and clamping workpiece installation process is called. Due to the workpiece position and orientation error, error called for clamping deformation and the error is
7、 called clamping error. Positioning error and clamping workpiece installation error named error. Because of this all parts for 21 kinds of workpieces, so the scheme is key to determine the fixture clamping deformation control at will The smallest. While clamping deformation control cannot rely on op
8、erators to realize in the past shell parts and machining by small and reliable clamping force to reduce clamping deformation, this will inevitably produce adverse product. In the introduction of domestic product technology at the same time, dont 2 notice the processing technology, especially the she
9、ll parts, production batch processing, different, use equipment that needs are different, clamping orientated in the introduction, digestion and absorption and must therefore in the design process, according to the actual needs of clamping positioning in blank, add uniform positioning and clamping p
10、oint. The selection principle of orientated may not deviate from the principle of localization, but at the time must note in the selection, I truly, Planar 3 point must form a stable support, namely the gravity of the triangle, near the workpiece center turn against restrictions freedom 2 some farth
11、er, the more accurate positioning. In parts of the shell, the key process is first step - graphic processing. According to the production batch and parts The structure and the precision, some parts processing, some parts of planar alone on a plane and hole machining process. Graphic processing quali
12、ty directly cause the whole process, the success or failure. Surface processing, mainly is bad, the flatness of the flatness of the next procedure of processing produce larger clamping deformation, clamping, precision parts in tolerance, loosen, clamping displacementrestoring, precision parts will c
13、hange, and with regularity. Surface processing by fixture causes adverse has two main: 1, the location selection is not reasonable, 2, clamping point is not reasonable. Therefore, the shell parts processing, surface of fixture design becomes important. In the traditional processing, for milling mach
14、ining processes, plane commonly, add a few auxiliary support to prevent due to the distortion caused by cutting force influence, because high-speed cutting machining precision cutting force, so, no need additional support commonly. In the face of processing, must consider the process of flexibility,
15、 can use the car is not to milling machining. In clamping point, on the choice of pay attention to the following problems: 1. By 3 strong point to form a support to support workpiece surface, can avoid blank piece of planar degree due to the deviation caused the machined surface flatness, and suppor
16、ting and clamping point should avoid a moment, and led up distortion. Because of clamping workpiece elastic deformation, loosen the clamping after springback, can cause planar degree, it is super flatness of the main reason. 2. The best point and clamping point is the sphere, ensure all, otherwise,
17、it will point is because the plane deformation caused by torsion blank clamping deformation. The 3 deformation will also cause planar degree. 3. When the workpiece surface cannot clamping, can use flank clamping, if clamping parts is deduced.and, must increase in the block, to avoid clamping deforma
18、tion. The clamping way, had better not use or using other techniques, or request processing plane designers in clamping point increase in design. 4. Because of the high-speed machining cutting force and deformation of more than 30% reduction processing, generally recommend that dont add additional s
19、upport can guarantee machining accuracy. 5. 2 limit rotational degree of freedom, the distance as far as possible, orientated if blank has note hole, 2 (note hole taper pin location using elastic is the most simple positioning scheme. In the design of the group clamps, considering the problems at th
20、e same time, we also need to consider many parts adopt a fixture, and replacing time processing varieties in a short time to finish. So the fixture design must consider quick change. This fixture is typical of six principles of fixture, positioning clamping adopt pneumatic clamping screw. This fixtu
21、re locating adopts point positioning forms, interface, nearly may also used clamping point, ensure orientated and clamping point in the same line, this fixture milling face results in the plane degrees below, the precision of 0.02 from the Angle of subsequent processing position from the Angle of us
22、e or can be very well meet the requirements. In addition, in parts processing process, for a process, whether to use fixture, use what type of clip What class, and the use of fixture in jig design must be carefully considered before. Besides the machining quality assurance from view, should also do economic analysis to ensure that the design of fixture in the economy.
