Multi-perspective
characterization of an end mill
In the tooling industry, optical metrology is crucial
in achieving success from both design and tool
use perspectives. Optical profilometers provide
valuable information to help manufacturers
optimize their tools and processes.”
One of the critical applications of optical metrology in tooling is the dimensional
characterization of cutting tools to ensure that tools perform optimally andhave a long service life. In addition to dimensional characterization, roughness
measurements can be interesting for predicting how well the removed material
will exit the tool. This information is critical in preventing clot formation or
overheating of the tool during use.
Optical metrology systems can also provide local measurements to help
identify potential cutting tool issues. For example, these systems can detectchipping or coating peeling, indicating that a tool needs to be replaced orrepaired.

CASE STUDY MULTI-PERSPECTIVE CHARACTERIZATION OF AN END MILLThis work was carried out by Digital
Surf and Natalia Bermejo fromSensofar.
Digital Surf is a software company
that specializes in surface imagingand metrology. The company offersa range of solutions for analyzing
and characterizing surfaces at themicro- and nano-scale. Digital Surf’s
software platforms enable users toprocess and visualize surface datafrom various sources. With a global
network of partners and distributors,
Digital Surf serves customers in
automotive, electronics, and moreindustries.

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It is important to note that these characterizations can come in very different
orders of magnitude. Dimensional measurements of common end mills,
for example, are typically within the millimeter range, while chipping orroughness assessments generally are on the micron scale. Yet, it is nowadays
possible only with one set-up: a Sensofar system, the S neox Five Axis, withDigital Surf software, SensoMAP.

Figure 1 shows the total 3D

measurement of an endmill
taken with the S neox Five Axis.
This measurement provides acomplete view of the endmill’ssurface, allowing for accurate
analysis and assessment.

This case study aims to share a multi-perspective characterization of a hardsteel cobalt squared end mill 4 flute square (Figure 1).

3D SHAPE ACQUISITION
Optical metrology systems like Sensofar’s S neox Five Axis are critical incharacterizing various parts and optimizing manufacturing processes in thetooling industry. The S neox Five Axis system can acquire the entire 3D shapeof objects, including end mills, and offers high precision and accuracy.
One of the key features of the S neox Five Axis system is its rotational module,
which allows for the complete measurement of a sample’s shape. This feature
is particularly useful in the tooling industry, where precise measurements ofcutting tool geometries are critical to achieving optimal performance.
The S neox Five Axis system offers three technologies: Confocal, Interferometry,and Active Illumination Focus Variation (Ai FV). That set of measuring
technologies has made us capable of measuring multiple things in tooling likeroughness, cutting edge, the entire shape of tools, and micro-tools. Although
in this case, Ai FV is the preferred choice y due to its fast measurement speeds
and superior ability to measure slopes.

CASE STUDY MULTI-PERSPECTIVE CHARACTERIZATION OF AN END MILL2■ Measurements
After acquiring the necessary data, we analyzed the mesh datacomprehensively. This is where the Mountains software proves extremelyuseful, particularly its Shell Module, which allows for extracting informationfrom mesh data at various levels.
The Shell Module of SensoMAP software is a powerful tool that enables users
to extract dimensional and roughness information by navigating from mesh to
topographical data and then to profile data. This module provides an effectivemeans of obtaining valuable insights from the acquired data.

DIMENSIONAL ANALYSIS
In our analysis, we performed several measurements using parametricprofiles generated from shell data to understand the endmill’s geometrycomprehensively.
The first measurement involved extracting cross-section measurements
perpendicular to the cutting axis of the endmill at multiple locations along theflute length (as shown in Figure 2). By doing so, we could determine whether
the tool maintained a consistent external diameter across its entire length.
Additionally, we calculated the concentricity between the inner and outercircles to check for any tool run-out.

Figure 2 , cross-sections

perpendicular to the tool axis
are taken with a separationof 1 mm to check the flute’s
diameter uniformity.

CASE STUDY MULTI-PERSPECTIVE CHARACTERIZATION OF AN END MILL

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The second measurement aimed to examine the pitch of the helix. To achievethis, we fitted the tool into a cylinder and unrolled it. Next, we extracted a
profile perpendicular to the helix angle and measured the pitch distance(Figure 3). This measurement provided valuable insights into the endmill’s
geometry and was crucial in ensuring it functions optimally.
Figure 3 displays an unrolled

tool image on the right and apitch distance measurement onthe left.

ROUGHNESS ANALYSISThe surface finish of the edges plays a crucial role in determining the outcome.
Therefore, we utilized the previously unrolled data to take a profile on top of
the flute and calculated the roughness parameters according to ISO 4278.
By doing so, we ensured that the end part would have clean edges rather thanrough ones, which can negatively impact the quality and performance of the
final product.

Figure 4 displays the roughness

measurement from oneof the tool’s cutting edges.
This measurement provides
information on the surface
texture and can help determine
the tool’s wear and tear.

In conclusion, measuring the surface roughness of the edges using advanced
techniques and software, such as those employed in this analysis, is crucial inachieving optimal surface finish and ensuring that the end product meets thedesired specifications.

CASE STUDY MULTI-PERSPECTIVE CHARACTERIZATION OF AN END MILL

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PEELING ASSESSMENT ON A CUTTING TOOL
One of the most promising features of cutting tools is their coating, whichsignificantly impacts their durability and ability to withstand high-stressprocesses. Coated cutting tools have been shown to last longer andperform better than their uncoated counterparts. However, coating peelingis a significant concern and can significantly impact the performance anddurability of the tool.
Fortunately, the Shell Module from SensoMAP offers an excellent solution to thisissue by enabling the extraction of topographies from the mesh (Figure 4).

Figure 5 , the topographical data

is extracted from a complete
3D measurement to further
study the peeling for a detailed
examination.

By utilizing particle analysis, we can focus solely on the areas where peelinghas occurred and determine the extent of the damage. This allows us tounderstand the peeling area’s dimensions and decide whether it is limited tothe coating or if some material is missing due to chipping.

Figure 6 , showcases the useof automatic detection from
SensoMAP’s Particle Detection
module for peeling assessment.
This technology allows forquick and accurate detectionof any particles or debris on theendmill’s surface, which canaffect its performance.

By identifying the extent of coating peeling and chipping, we can takeappropriate action to ensure that the tool remains in optimal condition andperforms to its fullest potential.

CASE STUDY MULTI-PERSPECTIVE CHARACTERIZATION OF AN END MILL5

■ Conclusions
Integrating the S neox Five Axis and SensoMAP has proven to be an exceptional
solution for tooling applications. The S neox Five Axis’s innovative combinationof three different measuring technologies and a rotational module has madeit an indispensable tool in the tooling characterization process. Additionally,SensoMAP provides a comprehensive suite of analysis tools for shells.
This combination of SensoMAP and S neox Five Axis made it possible tocharacterize an end mill’s dimensions, roughness, and peeling defects. With
this innovative technology, manufacturers can achieve unprecedented levelsof precision and accuracy, making it possible to produce high-quality productsthat meet the demands of today’s market.

CASE STUDY MULTI-PERSPECTIVE CHARACTERIZATION OF AN END MILL

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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 andquality inspection laboratories to complete non-contact
metrology solutions for in-line production processes. TheSensofar Group has its headquarters in Barcelona, also known
as a technology and innovation hub in Europe. The Group isrepresented in over 30 countries through a global networkof partners and has its own offices in Asia, Germany and theUnited States.
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