Texas machine shop benefits by switching from plasma to waterjet cutting
Above: Kimbrell’s Kustom Machine Shop uses a MultiCam waterjet to produce a variety of parts at its 13,000-square-foot facility, temperature-controlled facility.
February 2023- Texas machine shop benefits by switching from plasma to waterjet cutting.
A successful machine shop must be able to handle practically every order that comes through the door, which requires being able to cut a variety of workpiece materials in a host of sizes.
In order to cut a larger variety of materials and do so more cleanly than its CNC plasma cutter can and to bring abrasive waterjet machining work in house, Kimbrell’s Kustom Machine Shop purchased a 3000 series CNC waterjet with a 5-ft. by 10-ft. table two years ago from Dallas-based MultiCam Inc., says Scott Kimbrell, co-owner and vice president of his 16-year-old shop in Garland, Texas.
He examined some waterjets from other builders, but selected one from MultiCam based on two motivating factors. “The biggest things for me it was an American-made machine and [MultiCam is] based here in the Dallas-Ft. Worth area,” Kimbrell says.
An abrasive waterjet machine complements a machine shop’s existing equipment lineup because of its versatility, according to Rashad Galloway, MultiCam fabrication product manager. MultiCam also offers flatbed cutters, routers, lasers and plasma cutters.
“There are just so many materials that the waterjet can cut, so a job shop can branch out and explore other materials. [This could be] work they turn away when they only have a plasma because the plasma needs conductive materials where a waterjet does not.”
The list of workpiece materials that the job shop cuts is diverse, Kimbrell says, including stainless steel grade series 300 and 400, carbon steel grades A36 and 4140, aluminum, brass, Teflon and Delrin. “We cut everything. Plasma is faster, but the waterjet has been a better fit for us.”
In addition, Kimbrell notes that the waterjet is often used to prepare parts for the shop’s CNC milling machines, which can impart finer surface finishes. Waterjet-cut parts that aren’t finished in a mill are usually sent to a vibratory tumbler to knock off the burrs and generate a uniform finish.
Sometimes, waterjet surfaces are good to go. “A lot of our parts get tapped, and we can just waterjet the holes and not even go back and clean the holes up,” he says. “We can run a tap right through the hole afterward.”
ACCESSORIES
Galloway adds that the 3000 series is MultiCam’s “flagship waterjet” as far as options. “What that means is the customer can equip the machine with many accessories to improve the cost and time” spent on orders.
One option Kimbrell opted for to reduce cycle times and cut heavy-gauge workpieces, with thicknesses up to 4 in. being cut so far, was the KMT intensifier pump that’s rated at 90,000 psi instead of the standard 60,000- psi pump. To adequately dissipate the energy created by the higherpressure pump, Galloway says MultiCam designed the 3000 series with a deep catcher tank to hold enough water below the cutting area.
Kimbrell’s Kustom Machine Shop purchased a 3000 series CNC waterjet from MultiCam about two years ago.
Kimbrell’s shop also chose to equip the waterjet with an abrasive removal system. With the removal system, water in the tank is agitated so the garnet abrasive, along with the particulates from cutting and other debris, is suspended in the water and gets extracted through a piping system to a separator, Galloway explains. “It separates the water from the debris and then pumps relatively clean water back into the tank.”
Having an abrasive removal system prevents the shop from shutting down the machine for two or three days to manually remove the garnet and debris from the tank when it has reached its limit, Galloway adds.
Nonetheless, about once a year the shop must remove some sludge from the bottom of the tank after draining the water into containers, Kimbrell says. “It took a full day to clean it out.”
One aspect of abrasive waterjet cutting that Kimbrell says he quickly learned after installing the machine is that not all garnet is equal. After initially using some abrasive sand from a local distributor, he realized the importance of cutting with high-quality garnet. The shop switched to garnet from Barton International, which Barton has mined from the geologically superior garnet deposits of the Adirondack Mountains and select international sources.
Sign production is one of the numerous applications for abrasive waterjet machining.
The shop doesn’t recycle its garnet for re-use in the waterjet, but Kimbrell says it is repurposed.
CONSERVING WATER
The machine also has a water filtration system to reduce the cost and quantity of water consumption. Prior to purchasing the waterjet, Kimbrell says the shop sent a sample of its municipal water to KMT for testing. “We got a report back saying that our water here in Garland is substandard,” he adds, noting that one issue is a high level of calcium.
Without a filtration system, a 60-hp, 90,000-psi pump will use about 1.5 to 2 gallons of water a minute, according to Galloway. “Basically, you’re pouring money down the drain.” Instead, a shop might need to add 2 gallons of water to the tank that’s lost through evaporation and steam every week or so, depending on the season.
Kimbrell’s operates the waterjet up to 30 hours a week, depending on the workload, Kimbrell says.
When a customer emergency arises, the shop can quickly process a plate, for example, he notes. “Not too many people can get a waterjet cut part on a Saturday, but we can do it. Sometimes we have to turn the part around in an hour, and we will.”
Some shop employees can operate the waterjet at its 13,000-sq.-ft . facility after he spends only two days training them. Although waterjett ing was new to Kimbrell’s at the time, Kimbrell says a CNC waterjet operates similar to a CNC plasma and he has more than three decades of experience as a machinist. “I’ve been around CNCs. I know how they operate. I understand them.”
Kimbrell’s shop is about 30 minutes from MultiCam and allows the machine tool builder to bring prospects and customers to Kimbrell’s facility to see the 3000 series waterjet’s capabilities.
3 Kimbrell’s shop also helps MultiCam with an occasional project. “I know we’re one of the only people in town that has the larger pump on our machine, so they’ve performed demonstrations quite a bit over here.”
Kimbrell’s Kustom Machine Shop, 214/227-5633, http://kimbrellskustommachining.com/
MultiCam Inc., 972/929-4070, http://multicam.com/
