New Approaches to Making Parts for the Oil Patch
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[Excerpt from full article by Ed Sinkorah, link to full article at bottom]
Cutting Tool Advances
While you might love to have a high horsepower monster for your fracking blocks, Allied Machine’s Deluca said they’ve increasingly faced the opposite challenge: the need to drill large holes with machines focused on milling where spindle speeds are higher but horsepower maxes out at 40 to 50.
“The companies making these parts are usually small to medium in size and typically not dedicated to making frack blocks,” he said. “And many people are leery of focusing on this market and spending half a million dollars on a machine for an industry that runs like a roller coaster. So we had
to develop a tool that can cut a 4″-diameter hole at much higher spindle speeds and much lower feed rates than our traditional drilling products.”
The challenge in drilling fracking blocks goes beyond the size of the required holes. “Interrupted cuts are inherent to fluid end block manufacturing since the cross-holes are drilled perpendicular to existing holes,” said Allied Machine’s Best. “Because of the resulting shape of the intersecting holes, the outside edges of the drill will continue to be engaged in the cut, while the inside edge will not. This can destabilize the drill, which can destroy the tool and damage the integrity of the fracking block.”
Also, if the customer is economizing by using material that hasn’t been heat-treated, the drill might encounter significant variations. Deluca of Allied said ordinarily that means an operator must constantly monitor the process or risk catastrophic drill failure within seconds of hitting a pocket in the casting, which might wreck a part you’ve put hours into. Shops also experience material variances from block to block, making it difficult to choose the perfect drill and operating parameters.
Allied has met these challenges with a “next-generation” tool called the APX. It features a tougher carbide substrate and a proprietary coating to withstand the shock of hitting a pocket. “You may chip the tool and you’ll get a squeal,” Deluca said, “but you’ll still be able to finish the hole.”
He added that Allied addressed the difficulties of cross-hole drilling by adding a wiper to the insert to improve stability, plus wear pads to provide additional stability when the pilot exits into empty space or a cross-hole. “We also recommend lightening the feed and maintaining the same speed when drilling angled exit holes so the tool doesn’t want to push off or walk. It’s usually not necessary when drilling the main line or the cross holes but there’s only so much engineering you can put into a tool to compensate for the extreme interrupted cut of the angled holes.”