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Figure 1: Angle measurement to verify clearance angle, wedge angle and rake angle in respect to the tool axis.
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Figure 2: InfiniteFocus for tool measurement. Alicona offers a range of metrology solutions to be used in the lab and in production.
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Figure 3: Chipping measurement. Users automatically measure edge quality parameters such as total depth, length and volume.
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Figure 4: Arndt Hauger, Product Manager Hybrid Processing in Germany about Alicona: “We are now able to machine PCD tools 30% faster.”
Vollmer is a manufacturer of sharpening and eroding machines for use in tool production and maintenance. To be able to machine state-of-the-art PCD tools, Vollmer developed the new Vpulse eroding generator. Before implementing this new machine, it was necessary to work out the ideal erosion parameters to ensure quality, precision, and efficiency. Vollmer accomplishes this by measuring finished tools with Alicona measurement systems. The world market leader particularly profits from Alicona's solutions for high-resolution 3D surface measurements and precise, repeatable edge-preparation measurements with close tolerances.
PCD is an extremely hard matrix of synthetically created diamond particles that is becoming increasingly relevant in the manufacturing of cutting tools. "In the machining of highly abrasive light-weight materials, cutting edges made from polycrystalline diamond provide customers with significantly longer tool lives compared to carbide cutting tools and ensure more precise machining of plastic, aluminum, magnesium, and wood," says Arndt Hauger, giving an insight into the world of PCD manufacturing.
Electrical discharge machining has the advantage of permitting highly precise sharpening of cutting edges. This method works by using electrical currents to generate discharges, which then remove microscopic amounts of material from a workpiece. The edge rounding of PCD tools, the proper edge preparation of the cutting edge is critical. It is this quality that determines the quality and service life of a tool.
Faced with the challenge of erode PCD tools in an optimal quality, Vollmer was in need of a flexible measurement system capable of solid and repeatable high-resolution measurement of cutting edges, roughness of the clearance surface and cutting-edge chipping. With Alicona, Vollmer now has a way of accurately inspecting the before mentioned quality characteristics and, consequently, identifying the ideal machining parameters for the Vpulse eroding generator. Vollmer's customers in turn profit from highest precision and reliability in the eroding of PCD tools. "Thanks to the repeatable measurements made possible by Alicona's systems, we have managed to strike the perfect balance between efficiency and quality in the machining of PCD cutting edges," product manager Arndt Hager reports.
Vollmer carries out measurements on finished PCD tools in order to identify optimum machine parameters. The InfiniteFocus system is used to achieve repeatable high-resolution measurements of the topography and geometry of a tool's clearance surface.
Examining clearance surfaces by measuring roughness
Secondarily a tools clearance surface determines a workpieces roughness, as it influences the chipping of the cutting edge. Alicona's 3D areal surface-texture measurement allows Vollmer to verify the roughness of the entire clearance surface, even of its curved parts. Measured values include profile-roughness parameters (Ra, Rz), areal parameters (Sa, Sz), volume parameters, and bearing area curve. True-color 3D surface visualization makes it easy to identify burns or impurities. Focus-Variation provides true-color information for any point of measurement. "The true-color pictures make it possible to quickly assess the results," Arndt Hauger confirms.
Assessment of cutting edge quality
Aside from inspecting the surface texture of the clearance surface, Vollmer also measures the geometry of the cutting edge with Alicona systems to check for cracks. "The main measurement parameters are radius, wedge angle, and chipping," Arndt Hauger explains. Vollmer uses Alicona's Chipping Module to identify chipping on the cutting edge. Other form deviations can be assessed using 3D difference measurement. This consists of comparing the edge's geometry to an imported CAD dataset or reference geometry in a fully automatic process. Form deviations are detected automatically and visualized using a special colour coding.
The following parameters of PCD-cutting edges are measured with Alicona in high resolution:
- areal surface roughness measurement of the clearing surface
- 3D visualisation of the surface
- radius- and form measurement of the cutting edge
- identification of chipping with the Alicona Chipping-Module
- 3D difference measurement to identify form deviations
"Our customers profit immensely from our ability to measure the geometry, edge radius, angles, and surface of PCD cutting tools after machining. It enables us to provide our clients with a more reliable and consistent service. Thanks to the optimum machine parameters for the new Vpulse eroding generator, we are now able to machine PCD tools 30 % faster and possible surface quality has improved by a factor of two and above." Arndt Hauger, product manager of hybrid processing.
Alicona Imaging GmbH