Vise Configuration Helps Company Achieve Tight Tolerances

Tescom Corporation (Elk River, Minnesota) is a global supplier of pressure regulators, valves and electronic controllers for a range of industrial and high-purity applications. Its Industrial Controls Division manufactures specialty regulators and valves for providing reliable control of fluids—gasses and liquids—that involve high-pressure, corrosive, flammable and/or unusual performance characteristics. These products are sold to end users in aerospace, chemical, testing laboratories, automotive, petroleum and various other industries.

The company had been using manually-operated, single-station vises from Kurt Manufacturing Company (Minneapolis, Minnesota). By combining two HDL double-station hydraulic vises and a manually actuated HDL vise on a 3016 machining center from Fadal Machining Centers (Chatsworth, California), the company experienced a 50 percent increase in productivity for its valve body machining operations.

"We needed to increase our valve body output using our existing machining centers, with the goal of transitioning our processes into new machines down the road," reports Brian Caldwell, Tescom's machine shop manager. "After examining a range of workholding options, we selected the HD vises as a solution to our expanding needs."

According to Tescom, the upgrade enabled it to transition economically into a more productive and flexible workholding setup to accommodate the more than 500 different valve body models and sizes that comprise the company's product line. The change also allowed the company to continue to use more than 300 sets of existing quick-change jaws. The company says that retaining these machined jaws has saved it thousands of dollars while eliminating the need to purchase, machine and inventory new jaw blanks.

"Precision tolerances, as well as overall surface finish, are crucial for these valve bodies to function reliably, and the Kurt vises clamp them well," explains Mr. Caldwell. "We maintain consistent ± 0.002 tolerances for the sealing area. The entire valve body radius has a 25 Ra finish, which acts as a metal-to-metal seal. We achieve a 32 Ra finish below the threads, where the valve closes. All contours are machined and have a consistent, high-quality appearance after using the new workholding configuration.

"Between three and five different setups are made on one machine, with as many as 100 individual valve bodies completed within a given 24-hour period," continues Mr. Caldwell.

With room for a third vise on the Fadal machining center worktable, Mr. Caldwell and his engineers recognized an opportunity to handle "few-of-a-kind" and/or oddly-sized valve bodies.

"We positioned the manual HD vise alongside the hydraulic models to accommodate low quantity and less frequently needed valve bodies," says Mr. Caldwell. "Our goal is to keep workholding costs low, and using the manual vise helps us accomplish this. We also liked that the vise easily converts to hydraulic operation if we choose to do so. There are plans to acquire new machining centers to replace the old machines in the near future."