a)Three-dimensional data model
b)Two-dimensional data model
Figure 1: Drum-shaped thin-walled aluminum alloy shell
The specific processing plan [3] formulated is as follows.
1) Processing is divided into three stages: roughing, semi-finishing and finishing. In the rough machining stage, most of the margin is removed while ensuring that the shell has sufficient strength; in the semi-finishing stage, the flanges at both ends and the inner shape are basically formed with a small margin, and the end holes are processed; the finishing process is divided into The key parts are processed in two steps, the first step is to process the flanges at both ends and the inner shape to the process size, and the second step is to process the entire outer shape to the process size.
2) Arrange stress relief and aging treatment after rough machining, semi-finishing and before finishing to remove the internal stress generated during part processing and reduce stress deformation to ensure dimensional and geometric accuracy.
3.2 Fixture design
The design of the fixture is the focus of the processing of this part. In order to ensure the dimensional and geometric requirements of the part and enhance the rigidity of the part, the fixture must have the functions of clamping, positioning and supporting at the same time. The designed fixture is shown in Figure 2. The fixture includes a cylinder ( The inner diameter is 210mm), A support plate, B support plate, adjustable support column, rubber protective cap, open wedge ring, compression nut and other components [4,5]. One end of the cylinder is provided with a clamping end, the middle cylindrical array has cross-set threaded holes, and the other end is provided with sliding parts and threads; the inner stop of the A support plate matches the clamping end of the cylinder with a small gap and is fixed with screws; Install the locking nut on the adjustable support column and place it together in the threaded hole on the middle cylinder of the cylinder. Put the rubber protective cap into the other end of the adjustable support column; the inner tapered hole of the B support plate and the outer end of the open wedge ring The cone surface fits and is inserted into the sliding part of the cylinder at the same time; a station for clamping parts is formed between the A support plate and the B support plate; the compression nut is placed on the thread of the cylinder and the open wedge ring is pressed to wedge it It is inserted between the B support plate and the sliding part of the cylinder, so that the B support plate and the sliding part of the cylinder are closely connected; the rubber protective cap can not only play a supporting role, but also play a role in reducing vibration and protecting the surface of the workpiece.
Figure 2 Fixture
1. 3—M12 screws 2—A support plate 4—cylinder body 5—rubber protective cap 6—adjustable support column
7—B support plate 8—M6 screw 9—Split wedge ring 10—Compression nut
2) Perform an aging heat treatment to fully release the internal stress of the workpiece.
3) Semi-finishing, the flanges at both ends and the inner shape are basically formed with a 1mm margin, and the end holes are processed.
4) Perform another aging heat treatment to fully release the internal stress of the workpiece.
5) Finish the inner shape and both ends of the workpiece to the process size requirements. The wall thickness of the workpiece is 5mm when the processing is completed.
Figure 3: Parts mounted on fixture
1—Cylinder 2—A support plate 3. 10—M6 screws 4—M12 screws 5—Workpiece 6—Rubber protective cap
7—Adjustable support column 8—Locking nut 9—B support plate 11—Open wedge ring 12—Compression nut
Figure 4: Connection between the pressure plate at the left end of the fixture and the workpiece
Figure 5: Connection between the pressure plate at the right end of the fixture and the workpiece