Operation 30 is the penultimate operation of shaping the workpiece. The general technological process of the rollers indicates that the shafts technology provides for the machining of splineways before finishing. Looking at the basic general technological process of a stepped shaft without heat treatment, the splineways (on the external surface) are made after shaping. If, as in the present case, there are no external threads, or cross holes, the machining of the splineways precedes the finishing.
In the case of the discussed operation 30 (fig. 1) we deal with the machin of a 15H10 groove. Fit H10 is a clearance fit. The arrangement of this groove and the clearly fit indicate that the groove in the design of the discussed shaft is not a splineway. This is a good example of the fact that the use of general (typical) technological processes requires a flexible approach. In this case, it is important to process the planes on the external surface. Whether these are actually splineways or similar surfaces is not so important.
Technological operation 30
Table 1 shows the technological cuts of operations 30.
|Cut No.:||Technological cut:|
Shaft technology means not only the machining of cylindrical surfaces. Grooves on external surfaces are made by milling. In the accepted convention of the technological process with the use of conventional machine tools, the groove is machined in technological operation 30 in a vertical milling machine (fig. 2).
In order to make a groove (figure 1) it is necessary to design a fixture using a prism and clamp. The fixture is set using the so-called slide block on the table with T-slots. Fixing to the table is carried out by any available method.
Milling set block
Determining the tool requires the design and use of the block set. Figures 3 and 4 show examples of milling fixtures. It has been developed for the machining of parts of the sleeve class and the implementation of the groove in the flange. This example, however, shows the idea of using a block set for a milling cutter. The PLGc type of block set is a top angular milling block set. Nowadays, these types of block sets are no longer used.
The examples of fixtures in figures 3 and 4 do not show exactly the machining as in the case of the technological process under consideration. The above machining fixtures (figures 3 and 4) use the upper angular milling block set.
The design of this type of machining fixtures is economically justified in series production. The cost of designing and making special technological equipment is distributed over the number of processed items.
In the case of using more modern lathes, especially CNC lathes with the possibility of milling, operation 30 can be made as a technological cut in operation 10. Shaft technology today uses CNC machining centers, often two-spindle with the possibility of milling (transferring the power to the tool head) – fig. 5.
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The technological process of this shaft with the use of CNC machine tools will be discussed in a separate article.
- Feld M., Podstawy projektowania procesów technologicznych typowych części maszyn, WNT 2000
- Puff T., technologia budowy maszyn, PWN 1985
- Maciej Horczyczak Ph.D. – knowledge and consultations
- External turning – SANDVIK