Cutting edgemeasurementof an insert
Whirling inserts are used to produce threads. The whirling process is complex,
that’s why there are many different angles (lead angle, angle of rake, clearanceangle) on an insert (Figure 1a). In addition, there are inserts with up to 3 teeth
on it. This makes it very difficult to measure an insert.
For previous quality assessments, one had to rely on simple optical devices
for assessing the dimensional accuracy and on stylus devices for measuring
roughness. The informative value of these measurements, however, is verylimited. In addition, the parts often had to be destroyed so that the desired
size could be measured. In order to constantly improve the quality of ourtools, there is a need for a flexible device to measure and assess both criticaldimensions and surface roughness of cutting tools.

UTILIS AG is one of the world’s
leading suppliers of precision tools
for the metalworking industry.
For more than 100 years, we havebeen developing, manufacturing
and distributing high-quality andprecise cutting tools, especiallyfor micromechanics, watch andmedical technology. Using stateof-the-art, advanced technologies
and the breadth of know-how inmanufacturing cutting tools, weposition ourselves as specialists andone of the market leaders in themetal cutting industry.
Authors: Thomas Forrer– Head of
Research & Development (right),
Paco Neuhaus – Application
Engineer (left)

The purpose of this case study is to measure the cutting-edge radius of aninsert with a 3D optical profiler and also extract the roughness parameters
along the edge of the cutting tool. A schematic drawing of the insert to bemeasured is shown in Figure 1b.
CASE STUDY CUTTING EDGE MEASUREMENT OF AN INSERT1abFigure 1. a) Some of the parameters of interest in a cutting tool. b) Drawing of the measured

insert. The red line shows the cutting edge profile that is under evaluation in this case study.

■ Measurements
The cutting-edge radius is very important for a good tool life expectancy. For
this particular application note, we used the Fixe Axis 3D Optical Profilometerin Focus Variation HDR mode (Sensofar), in conjunction with a 100X Objective
magnification, to acquire the cutting edge 3D topography of an insert (Figure2). It is worth noting that for this particular sample, a Confocal techniquewould have provided accurate and robust results as well. The insert was held
as shown in Figure 3 with an elevation angle of 63.5º.
Figure 2. On top we see the 3D topography of a rounded cutting edge measured with 100X

Ai Focus Variation HDR. The transversal profile is shown at the bottom and the top-view on theright hand side.

2CASE STUDY CUTTING EDGE MEASUREMENT OF AN INSERTFigure 3. Positioning of the insert under the S neox Five Axis 3D optical profiler.

Once the topography was acquired, the data was sent out to the SensoPROsoftware ‘Edge’ plug-in for automated data analyses. This software module
can automatically detect the cutting edge orientation and computes acertain number of profiles that are transversal to the edge. For this particular
example, we chose up to 30 profiles, from which the cutting edge radius,
among many other parameters listed in Figure 4, were computed.
Items
r
αβγ
SαSγ
KDαDγ
Kd
WrUnitsμmdeg
degdeg
μmμmμmμmμmμmμmDescription
Radius of the cutting edge
Clearance angle
Angle between rake and flank face
Rake angle
Cutting edge segment on flank face
Cutting edge segment on rake face
Relation between Sγ and Sα
Flank face distance to the tangent
Rake face distance to the tangent
Relation between Dγ and DαEdge widthrβα

Υ

SaSyK

Figure 4. List of parameters computed for each profile transversal to the cutting edge. Inaddition to these parameters, the software also computes roughness (e.g., Ra, Rq or Rz amongothers) along the cutting edge.
CASE STUDY CUTTING EDGE MEASUREMENT OF AN INSERT3

The SensoPRO software allows for visualization of each parameter andprovides some statistics on each parameter (i.e., mean value, standard
deviation, minimum and maximum). As shown in Figure 5, the averageradius of 30 profiles is 5.14 µm with a standard deviation of ±0.35 µm. It isalso worth mentioning that the software allows setting a tolerance range andexporting the results in a Pass or Fail Report, in our case, we set a minimumand a maximum cutting edge radius of 4.7 and 5.7 µm, respectively, whichcan be seen at the bottom plot in Figure 5 (i.e., orange region).
Finally, one last parameter of interest is the roughness at the edge of thecutting tool. This information is provided automatically by the software in
the form of many common and standard parameters such as Ra, Rz and Rq,
among others. In this particular case, the cutting edge had an Ra of 0.05 µm.
bdacFigure 5. Outcomes of the SensoPRO ‘Edge’ plug-in . a) List of cutting-tool parameters. b) oneout of the 15 transversal profiles with the corresponding cutting edge radius, clearance, andrake angles. c) The out-of-tolerance region (shown in orange) in a plot of cutting edge radius(y-axis) vs. each profile number from 1 to 30 (x-axis). d) Example of a cutting-edge topography
with the transversal profiles.

4

CASE STUDY CUTTING EDGE MEASUREMENT OF AN INSERT■ Conclusions
The 3D optical profilometer S neox Five Axis makes it possible to quickly andflexibly obtain the key parameters necessary for the continuous improvementof our tools, such as the cutting edge radius, clearance and rake angles, oreven the roughness at the edge.
In this particular case study we successfully measured an average cuttingedge radius of 5.14 µm and a roughness Ra value of 0.05 µm at the edgeof the cutting tool. This information was easily obtained using the Ai Focus
Variation technology, with a 100X objective magnification and with theapplication-specific software, SensoPRO (‘Edge’ plug-in).
Having three measuring methods present within the same sensorhead (i.e.,Confocal, Ai Focus Variation and Interferometry) allow for a very flexible
measurement of different measuring tasks on various parts. From very smoothand shiny to heavily textured, rough surfaces: everything is possible with theS neox Five Axis. Steep angles and very small cutting-edge measurements ofa few micrometers are no longer a problem for 3D optical profiling.

CASE STUDY CUTTING EDGE MEASUREMENT OF AN INSERT5SENSOFAR is a leading-edge technology
company that has the highest quality standards
within the field of surface metrology
Sensofar Metrology provides high-accuracy optical profilers
based on confocal, interferometry, focus variation and fringe
projection techniques, from standard setups for R&D and quality
inspection laboratories to complete non-contact metrology
solutions for in-line production processes. The Sensofar Grouphas its headquarters in Barcelona, also known as a technology
and innovation hub in Europe. The Group is represented in over
30 countries through a global network of partners and has its own
offices in Asia, Germany and the United States.
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