TAKAMAZRYU-GIWe have verified a method for effectively dealing
with the stagnation of chips that impedes efficient
inner diameter finishing.

vol.20Measures against chips in inner diameter finishing
Current inner diameter finishing
Chip disposal is greatly affected by the properties of thematerial, and it is very difficult to break up chips of copper,aluminum, and press worked materials such as mild steels, inparticular.
There is little freedom to adjust the feed rate and depth of cut
in the turning process, and the chips interfere with the workpieceand do not curl enough, which makes them difficult to expel during
inner diameter finishing, and also greatly affects the utilization
rate and stability of quality in mass production.

to provide a location where the depth of cut fluctuates. Then, byfinishing with a depth of cut of 0.5 mm as shown in Figure 2, wewere able to make chip breaks whose point of initiation was theposition where the depth of cut changed (Figure 3).
Since the lengthwise groove depth is shallower than the finishing
depth of cut, there is no groove mark left on the finishedsurface.

Toward reliable chip removal
In the situations where chips are difficult to expel, proper chip
removal is considered to improve the utilization rate and quality
on production lines. We verified the possible solution to reliablechip removal during inner diameter finishing.

Intentional creation of variations
in depth of cut
Due to the evolution of chip breaker design, the chips are tightly
curled, but in situations where the depth of cut and cutting
conditions are restricted, as is the case with finishing, theprobability of chip breaking is rather low without making somechange, such as changing the depth of cut during turning.
Therefore, we decided to provide variations on the surface of theworkpiece and deliberately create conditions where chip breaking
would be initiated at those variations.
The specific strategy was to make a lengthwise groove on the innersurface before starting the inner diameter finishing, providing alocation where the depth of cut could be changed once every
revolution as the point of initiation of chip breaking.

Validation results
A lengthwise groove was created on the aluminum (A5052) workpiece
to a depth of 0.3 mm using a slotter tool (special tool of
Sumitomo Electric Industries, Ltd.) as shown in Figure 1,

Finishing with adepth of cut of
0.5 mmFigure 2

Reliable chipbreaking
accomplished

Figure 3

Supplementary note
Because changing the depth of cut causes the cutting load tofluctuate, if the tool or the workpiece itself has poor rigidity,
the amount of deflection may change momentarily and affect theroundness.
An essential condition for this solution is to use a rigid tool,
which will enable stable cutting while breaking the chips.

Lengthwise groove
cutting to adepth of 0.3 mm

Click here for a video of the actual cutting!!

Figure 1

In order to continue to provide machines that earn money and to propose high-efficiency
cutting methods that make even better use of these machines, we will help to improve ourcustomers’ productivity by taking on difficult challenges and finding ways to resolve them.
Contact: 076-274-1402
Technical Sales & Cutting Division, Sales Affairs Department

Click here for TAKAMAZ RYU-GI Vol.1-19!!