After the improvement, a large pad is added under the original fixture, and the large pad is integrated with the pad, the cylindrical positioning pin and the chamfered positioning pin in the original fixture. In order to ensure the accuracy, the machining center is used for careful processing. The key guarantees two points: 1 large pad edge and parallel to the center line of the two cylinders, the parallelism error is not more than 0.015mm. In this way, when the fixture is being corrected, it is only necessary to use the dial gauge to find the straight edge, and it is convenient and easy. 2 The perpendicularity between the two cylinders and the bottom surface of the large pad is not more than 0.015 mm. The effect diagram in actual processing is shown in Figure 5.
Figure 5
The steps of the improved method are as follows:
(1) Find the straight edge of the fixture.
(2) The CNC machine tool executes the NC program that has been programmed, first machining the outer arc and then chamfering.
(3) Remove the workpiece, turn it over and re-clamp, and machine the reverse chamfer.
After several batches of parts processing practice, the effect is very good, the knife is convenient to find, the overall rigidity of the clamp is good, and the chamfer is symmetric and uniform. The appearance quality of the parts has been well received by customers.
4. Summary of results
In the actual production application, the fixture greatly improves the clamping speed, improves the production efficiency, and ensures the machining accuracy. We will compare the improved fixture with the improved fixture (50 batches of parts):
Use the fixture before the improvement:
(1) At least three to four times should be re-aligned during the processing of a batch of parts.
(2) Since the rigidity of the jig is not good, the cutting force cannot be too large, so sometimes it has to be layered.
(3) The phenomenon of uneven chamfer often occurs, which directly affects the appearance of the parts.
(4) It takes about 3 days to process a batch of 50 parts.
Use the improved fixture:
(1) There is no need to re-align during the processing of a batch of parts.
(2) The rigidity is improved without layering processing.
(3) The chamfer is even and the appearance is beautiful.
(4) Processing a batch of 50 parts a day and a half, the efficiency is doubled.
This fixture can also be used for other similar workpiece machining, convenient, efficient and reliable.
For more exciting articles, please refer to Metalworking, Cold Processing, 2008, Issue 2
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