T a k a m a z RY U - G I
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The 12th SMART GROOVE CUTTING

In groove cutting, there arecases where good surface
finish and roundness are
required depending on
the dimensions a groovemust provide. Although
the walls on both sides ofa groove can be accurately
finished by cutting, it is
not always easy to finish
the bottom face to the specified surface roughness,dimensional tolerance and roundness for some kindsof workpiece material. This is due to the natureof groove cutting in which the entire width of acutting edge engages in cutting. We studied a newcutting technique and conducted tests to findthe limits of the achievable surface finish androundness at the bottom face of a groove forthe purpose of further study and improvement.
* This new cutting technique which uses a special
tool is now under feasibility tests and therefore
will not be discussed in this article.

Test Environments
General Cutting

Smart Groove CuttingWorkpiece material
Cutting speed
Coolant
Cutting oilTool

S45C drawn bar
110m/min0.1mm/rev
Water-soluble
GBA43R300/PR930

S45C drawn bar
250m/min
0.05mm/rev
Water-soluble
TIALN coating

Machine model

TAKAMAZ X series

TAKAMAZ X series

Test Results
General cutting: Surface roughness
12.0Ry(2.5Ra)

Smart groove cutting: Surface roughness
2.10Ry(0.25Ra)

Other Features
1. Cutting of groove bottom surface with gentle
rounding or taper profile is possible.
2. High-speed groove finish cutting exceeding
200 m/min cutting speed is possible.
3. Can be applied to various kinds of workpiecematerials including aluminum, casting aswell as hard turning.
The figure below shows the results of test
cutting by programming the groove bottom shapewith 50 μm concaved into a tapered profile
with corner rounding. We found that the contouring
by the programmed values is possible.
Taper 50μm

R50μm

Purpose of Use
This cutting technique is used for improving
the surface finish of the bottom face of O-ringgrooves. In addition for OD turning operation
where a grooving tool has to be used to avoid
interference, surface finish improvement isexpectable. In the future, this technique will
be able to eliminate grinding operation after
OD turning and extend tool life in cutting
hard-to-cut materials.

Applications
The graphs below show the surface quality
achieved in end face and OD turning on Super
Alloy 718 (heat resistant steel). Cutting waspossible up to 2.5 km cutting distance in 60 min.

Ry3.3(Ra0.55)【初期 Ry3.3(Ra0.42)】

Conclusion

For the test, a drawn bar made of S45C which isprone to get a rough surface was used. Using astandard tool with the general groove cutting
method, the surface finish deteriorated gradually,
but using a special tool with smart groove cutting
realized good surface finish. Although the material
we used in the test is difficult to obtain goodsurface finish with, we believe good surface
roughness can be maintained with other workpiecematerials as well.

The cutting technique discussed in this article
is still under testing and we will continue
further testing with various tool shapes anddifferent materials. ID grooving will also
be tested.