Previous entry in the series: Technological process of sleeve, part 2
Figure 1 shows a technological sketch for this technological operation. According to the principles of technical drawing, very thick lines mean surfaces machined in a technological operation.
|Cut No.:||Description of the technological cut:|
|3||Chamfer 2×2-45º na Ø110,5-1|
|4||Turn groove Ø44 o szerokości 2|
|6||Chamfer 2-45º na Ø39,5+0,2|
In operation 20 relative to operation 10, the workpiece setting and fixation has changed. The sleeve blank after the first operation was turned 180º. This operation involves machining the hole and finishing the outer surface from the other side of the workpiece. In this approach, however, the term ‘finishing’ means finishing from the point of view of the desired geometric dimensions and surface layer properties defined in the construction drawing.
In the first technological operation (10), a part of the axial hole of the sleeve was finished, so the final dimension (Ø30H8) was obtained. In this case, using this part of the hole as the base surface is not recommended due to the possibility of damage. It is necessary to use a different surface as the base, as was done in this operation (fig. 1). The issue of maintaining coaxiality of the machined hole surfaces is not a major problem. This is due to the fact that the surface of the Ø30H8 hole and the outer surface of Ø60.5-0.5 they were made from one fixation and therefore can be used interchangeably to base the object in the next operation. The use of a three-jaw chuck is easier than a small diameter hole. In the case of a three-jaw chuck, the jaw retaining surfaces must be grinded if the workpiece surfaces they are in contact with have already been machined.
In accordance with the principles set out in the general technological processes for part of the sleeve and disc class finishing of external surfaces should be performed based on the hole at the end of the technological process. However, each technological process should be considered individually in the context of the general process recommendations. Machining of sleeves and discs with the use of external surfaces as bases for shaping and finishing the hole is allowed.
Modern machine tools, tools and technological equipent (System Machine tool Workpiece Tool) allow obtaining increasingly narrow tolerances (better machining accuracy). Technological progress in the field of machine tools as well as a change in the nature of production to small series and the progressing customization of products mean that rigid rules become recommendations until now. The modern trend in machining is the pursuit of almost one-operation machining as far as possible.
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- Zgrubna obróbka otworów