(1) Structural features of parts
A part of the data is hard aluminum LY12, its good cutting performance, attributed to the typical thin-walled disk structure, the size of the larger, the thickness of the surrounding and internal ribs is only 2mm, the depth of the cavity is 27mm. If the technical plan or processing parameters are not properly set during the processing of the part, it is very simple to deform and form an oversize tolerance. The
(2) Skill Analysis
The blank of this part is made of bar stock, and the skill plan of roughing and finishing is selected. The detailed skill flow is as follows: rough→rough car→rough milling→aging→finishing car→finishing. Roughing car: Set aside a 1.5mm finishing allowance in the outer circle and the end face, and pre-drill the hole in the base. Roughing: Leave a margin of 1.5mm at the side and bottom of the cavity, and pre-drill the skill hole at the φ12mm hole. Aging: Remove data and processing stress. Finishing car: Finishing the surface of the fine car, and boring the skill hole φ6mm, the demand is clamped once, in order to ensure the coaxiality, and lay the foundation for the subsequent processing. Finishing: The final requirements of the parts are the main points discussed in this article. The
1 Roughing rough cavities is mainly to remove large margins and lay a good foundation for subsequent finishing. Therefore, when processing cavities, choose low-cost general digital control CNC machining and milling machines. The process needs to be processed according to the part structure shown in the internal shape summary, arc corner is R5mm, the remaining fine finishing allowance is 1.5mm. And this process also needs to pre-finish the positioning holes required for finishing in the φ12mm hole position. The
2 High-speed machining of high-precision cavities is a production skill that has been used in recent years. In high-speed cutting, because the cutting force is small, the processing distortion of the part can be reduced, and it is more suitable for thin-walled parts, and the chips are removed in a short time. Most of the cutting heat is taken away by the chips and the workpiece is thermally deformed. Small, help to ensure the accuracy of the scale, shape; high-speed processing can obtain a higher surface quality, the processing cycle is also greatly shortened, so contact the characteristics of thin-walled disc type, high-speed machining when used in the finishing cavity. The
3 Positioning hole processing The part finish machining uses the base hole φ6mm and φ12mm hole as the positioning hole, so it must be processed in place before finishing the cavity. The base hole φ6mm is cut into φ6H8 when it is φ301.5mm. The φ12mm hole is drilled and hinged to φ12H8 by digitally controlled CNC machining. The
(3) Positioning and clamping of parts during finishing cavity To enable workpieces to be installed on the machine quickly and accurately, and not to correct them one by one when processing a batch of workpieces, this process uses a two-pin positioning method. . The φ6mm and φ12mm holes already existing on the parts are used as the positioning holes to make a simple tooling. The tooling uses a cylindrical pin and a flat pin as positioning elements. Because the part is attributed to the thin-walled part, it is easily deformed. When clamping the workpiece, the pressure plate should be pressed on the part where the workpiece rigidity is good, distribution is as uniform as possible to ensure the reliability of the clamping, and the size of the clamping force should be appropriate. In order to prevent damage to the positioning of the workpiece or the workpiece does not allow deformation. Its detailed positioning and mounting. This clamping method fully conforms to the characteristics of the processing base, and one clamping can complete the processing of the cavity and all the holes.