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Rectangular grooves are produced in most cases immediately after plane surfaces and end faces have been machined.
Figure 17. Rectangular groove
Therefore, the position of the groove is determined by the positional accuracy of the base surface.
- Use the machine vice.
- When clamping the workpiece, pay attention that parallelism and angularity to the primary motion are ensured.
- Supporting and locating surfaces must be clean.
- Set the tool slide exactly to 0.
Figure 18. Tool slide in exactly
vertical position
1 ram head
2 tool slide
3 clapper box
4 ram
clapper
5 tool post
6 locking bolt
7 ram clapper pin
8 grooving
tool
9 workpiece
10 parallels
11 machine vice
12 feeding movement of
tool slide
13 angle of 90°
- The tool block stands vertically.
- If the groove depth is small and the overrun path sufficiently long, the tool can be lifted out of the groove during the return stroke. In this way the vertical side surfaces of the groove are not damaged by biting. If this is not possible, the tool block must be fixed.
- Align the straight primary cutting edge exactly parallel to the workpiece or table surface (fig. 18).
- Reduce the cutting speed by approximately 40 to 50% as compared with the table data, as flowing off of the chip is hindered by the side surfaces of the groove.
- After having scratched, work with a feed of 0.05 to 0.2 mm per double stroke according to the scale value.
- Machine grooves of low accuracy in one operation. The cutting edge of the tool has the width of the groove to be manufactured.
- During machining the tool is to perform cutting work, if possible, to prevent scraping of the primary cutting edge.
- Machine grooves of higher accuracy with a tool the cutting edge of which is 0.5 mm narrower than the groove.
- Position in such a way that on both sides an equally great machining allowance remains for finishing.
| At a machining depth of approximately 1 mm check positional and dimensional accuracy and correct, if necessary.
- Finish-machine the depth of the groove.
- Finish with a tool the width of which is ground accurately to size.
|| When working, never stand in front of the machine, but always beside the machine on the side of the control elements (splashing chips, danger of getting injured).
|| Check the workpiece or tool, on principle, only when the machine is at rest.
What has to be done, if by mistake the infeed of the tool in
relation to the final size has been set too
high?
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What criteria does the choice of the feed depend
on?
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Why is the cutting speed reduced by approx. 50% as compared with
the table data when grooves are to be
shaped?
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Why must the workpieces always be deburred after
machining?
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