Cutting Tool Engineering
August 2011 / Volume 63 / Issue 8

Erosion Efficiency

By Alan Richter, Editor

Eroding and polishing PCD- and PCBN-tipped cutting tools in one clamping helps ensure toolmakers accurately and efficiently produce those tools, and Vollmer of America Corp. has introduced a universal machine to do that. The QXD 200 is a 6-axis machine for manufacturing such cutters up to 250mm in diameter and 200mm in length.

To boost productivity, the machine has a generator that reduces EDM erosion times by up to 30 percent compared to the company’s previous generator, according to Scott Ries, product manager for the PCD group at Vollmer. The rotary, or disc, erosion process typically leaves 10µm to 20µm of superhard material for polishing with a grinding wheel, he noted.

Ries added that the erosion process is able to impart a cutting edge finish as fine as 0.18µm Ra, and a polished edge can be as fine as 0.05µm Ra.

QXD200-enlisch-WEB-13.tif
Courtesy of Vollmer

Through the integrated polishing capability, a toolmaker can produce a PCD- or PCBN-tipped tool in one clamping on the QXD 200 from Vollmer.

The machine can also measure the grinding wheels, electrodes and workpiece location within the machining environment. “The machine understands where everything is located and what the dimensions are,” Ries said, adding that the machine’s automatic toolchanger holds a combination of up to six wheels and electrodes. “It provides the versatility to run different geometries without having an operator change electrodes, change wheels or remeasure where they’re at because [the wheels and electrodes] were taken off and put back on.”

Because of the novel arrangement of the axes, a tool is machined in a suspended position, the company reports. Ries explained that Vollmer developed the vertical axis to improve tool runout because a tool can deflect due to its own weight when held with the conventional horizontal axis. That also helps keep the workpiece interface cleaner because debris is flushed down the tool. “It makes measurements more accurate as well,” he said.

To eliminate the need to tweak a 3-D model of a tool prior to producing it, Vollmer developed ExLevel software to create “an exact replica of that 3-D model” in which the manufactured tool’s tolerances don’t vary from the model, Ries noted. The virtual simulation program also enables end users to verify that a tool design is correct and, if not, modify it before production begins by importing the tool’s 3-D model into their modeling software, he explained.

The QXD 200 offers three options for delivering tools to the machine: a traditional magazine, a pallet system for 39 large-diameter workpieces and a pallet system for 64 small-diameter workpieces. The pallet systems are positioned on tracks outside the machine and enable integration of other parts of the manufacturing process, such as brazing and inspection, into the tool delivery system, Ries noted.

For more information about the QXD 200 and Vollmer of America Corp., Carnegie, Pa., call (412) 278-0655 or visit www.vollmer-us.com.

About the Author: Alan Richter is editor of CTE, having joined the publication in 2000. Contact him at (847) 714-0175 or alanr@jwr.com.
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