On-machine finishing saves valve maker time, money

January 31, 2018 2:10 pm

By Alan Richter

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END USER:  Wolfram Manufacturing, (512) 600-3220, www.wolframmfg.com

SOLUTION PROVIDER: Brush Research Manufacturing Co. Inc., (323) 261-2193, www.brushresearch.com

CHALLENGE: Perform finishing operations during the machining process.

SOLUTION: Tool with small, abrasive globules that are permanently mounted to flexible filaments.

For contract parts manufacturers, the ability to produce tight-tolerance parts at a faster rate is key to remaining profitable as competition continues to heat up. Therefore, those manufacturers constantly seek creative ways to reduce overall cycle times, including finishing operations.

Although machine shops may have auxiliary finishing equipment, the primary focus is on machining. As a result, many shops must outsource secondary finishing steps, such as thermal deburring, tumbling and burnishing.

However, for Wolfram Manufacturing, Austin, Texas, which machines metal parts with complex geometries on 4- and 5-axis machines, sending out parts for secondary finishing not only adds to the cost but can hurt quality and increase the time it takes to deliver parts to customers.

To complete the finishing tasks within the machining process, Wolfram Manufacturing applies Flex-Hone tools from Brush Research Manufacturing.  Image courtesy of Brush Research Manufacturing.

“There’s the additional time, not to mention the additional cost, of having someone else do the work,” said Tim Urano, former quality manager for the company. “In the competitive environment of today, we’re often faced with short lead times from customers. Having to send parts to an outside vendor eats into our lead time and takes significant planning.”

A better alternative, Urano said, is to complete the finishing tasks within the machining process. “Anytime we can incorporate secondary operations right into the machining process, we save time [and] money and reduce our work in progress.”

In one example, Wolfram Manufacturing was charged with making a part for a sliding valve assembly with complex internal geometries that required a fine surface finish on the internal bores, where the valve assembly actuates, and no sharp edges from drilling.

Sliding valves, which are movable elements in a system, direct the flow of a working fluid into the proper channel. The assembly is part of a larger product for pressurized, down-hole drilling.

To operate properly, the valves utilize O-rings that must be seated properly and maintain tight contact with the bore without being cut by any sharp edges from intersecting cross-holes or undercuts.

“The customer’s primary concern is that the O-ring seal is protected from being cut or damaged by any sharp edges or burrs,” Urano said.

To deliver the desired results, Wolfram Manufacturing applied the Flex-Hone tool from Los Angeles-based Brush Research Manufacturing Co. Inc. for in-machine finishing. The tool has small, abrasive globules that are permanently mounted to flexible filaments. In addition to deburring and edge blending, the tool is suitable for cross-hatching and removing cut, torn or folded metal.

“It’s very easy to put the flexible hone in a toolholder, give it a simple toolpath cycle and let it run,” Urano said. “With some of the other in-machine deburring tools, it can take complex 4- or 5-axis paths to be effective.”

“The part has some undercuts and some intersecting cross-holes, so we use the tool to edge-break and help blend the chamfers at the same time,” he added. “The hone is one of the only tools that can reach that edge. It doesn’t alter the feature geometry, but it rounds it enough that it won’t damage the O-ring.”

As part of a multiple-step process, Wolfram Manufacturing applies a coarse-grit Flex-Hone to smooth any irregularities left during drilling and then finishes the bore with a fine-grit one.

“Final finishing operations don’t accommodate much variation, so they need the uniform surface preparation that the flexible hone provides,” Urano said.

While Flex-Hones are often used with automated production equipment, offline deburring is another possible application. If any damage occurs to the bore finish during post-processing or inspection, Wolfram Manufacturing can go back in with the abrasive tool and repair it.

Urano added that Wolfram Manufacturing will continue to use the brush for applications with intersecting holes and fine surface-finish requirements in a bore.


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