Vollmer: Identify optimum machine parameters for accelerated production

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.

Erosion of PCD tools in optimum quality 

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.

The proper edge preparation of the cutting edge is critical 

The company's printed strips are used in the manufacture of connectors, contacts, complex semiconductor components and various other products. In virtually all of these applications, the printed strips and their fine geometries are highly customized individual solutions. Consequently, the development and production of customer-specific printed strips must be accompanied by innovative and process-integrated quality assurance. 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 to erode PCD tools in an optimal quality, Vollmer was in need of a flexible measurement system capable of robust and repeatable measurements to verify edges, clearance surface and 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 by Alicona we have managed to strike the perfect balance between efficiency and quality in the machining of PCD cutting edges“, product manager Arndt Hauger 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 along 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 truecolor 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 color coding.