Is CNC Making The Cut?

By Emerson Schwartzkopf

Look at the specifications for a CNC-based production machine, and you’ll see that it can make anything – but will it make sense in your shop?
The appeal for a do-everything device taking stone from slab to sink – or any other product – is tremendous. So is the price tag, with investments creeping into the mid-six-figure range, making for a tough decision.
Reports from the working front, indicate that the CNC machine strikes a good balance at a time of increasing competition and – in some places – a tight work force. The shop’s workflow seems to run faster and smoother … and owners seem to think that if it’s worth having one CNC, it’s a better idea to have two.

A FINER EDGE
Plenty of automated stone-finishing equipment falls under the general heading of CNC, or Computer Numerical Control, as a way of giving machines orders to cut, edge, polish, groove or some other task. The point-to-point system of directions using sets of coordinates isn’t exactly special.
CNC, in this case, refers to machines literally capable doing it all – sawing, routing, etching, finishing – using multiple tools (albeit one at a time). With roots in other industries, such as glass, CNC production machines now made for the stone trade are quickly finding homes in shops producing all types of work.
While CNC machines can do literally anything with slab-cut stone, its biggest impact may be with the proverbial kitchen sink … and just about any other bit of interior residential work. At Dixie Cut Stone in Bridgeport, Mich., there’s been a CMS-Brembana Maxima on the shop floor for more than three years – with a second one added last year – and it’s easy to see what’s Job #1.
“The main thing that we use our machines for is profiling kitchen countertops,” says Dixie Cut’s Randy Wiley. “And, if we have free-form tops with a radius or an arch, that’ll get run on the CNC as well.”
Dixie Cut doesn’t run the whole job from slab to finish on the CNC, Wiley notes, since the company uses 2cm material with lamination. After cutting stone with bridge saws, it’s a process of doing the edges and then applying the epoxy before the finish work.
The CNC also doesn’t do the final touches, although Wiley says the machines come close. “The degree that these machines can polish,” he says, “just makes it easier for the guys who are hand-polishing to fine-tune it from there.”
Wiley also cites edge work as a mainstay of the CNCs, including a triple-waterfall with three half-bullnose edges vertically stacked. “We also do some custom moldings and different 3-D profiles,” he says. “Doing them by hand would be so outrageously expensive that you wouldn’t even consider it.”
The CNCs also make it possible to do large quantities of granite farm-style sinks, Wiley says. “Our sink bottoms are made of 1 1/4” material where we create a 3/8” radius, so you don’t have a flat bottom where the edge of the sink comes down,” he notes. “We slope it to the drain, and on the CNC, we get a perfect shape.”
The CNCs also plays a part in a new business opportunity, where Dixie Cut produces tops for a line of cabinetry sold to dealers nationwide. The tops, in the 2’ X 4’ range, can often be done from remnants, cutting down on waste; the jobs can also be done with unattended CNCs overnight, keeping the machines in the regular kitchen-production cycle during the day.

START FROM SCRATCH
Working with remnants also plays a key role in keeping the Marmo Meccanica CNC running during the workday at HBF Marble & Granite in Denver. For HBF – a company focusing on home interiors in the Denver metro area – it’s not a matter of just filling time, either.
“We take remnants and make preprogrammed coffee-table and round-table tops,” says HBF’s Joe Hyde. “It gives us the ability to do some things with our remnants that would take us a lot of time to do otherwise … and our remnants don’t have to be square, either.
“It gives us the ability to sell for less, people get a better deal for their stone, and everyone’s happy.”
Most of HBF’s work remains in kitchens, much like Dixie Cut. However, while Dixie Cut brought CNC into the shop after close to 30 years in fabricating stone, HBF started its operations from scratch in the late 1990s – and made CNC a key part of the workflow from day one.
Hyde notes that HBF’s owner, who also operates a flooring company, saw an opportunity in stone while attending a Coverings trade event, and struck a package deal to fully equip a brand-new facility. “When we decided to get into the granite business,” Hyde says, “we started out shop with all the machinery already in place.”
HBF brought in some experienced hands, who helped to train the rest of the crew. The CNC’s ability to do multiple jobs, as it turned out, ended up being a large help as well.
“In a traditional shop, it would take years to train someone to do everything,” Hyde says. “When we can take a job with the CNC 85 percent of the way there, we only have to teach them an aspect of the job to finish – and then we can take our time teaching them other things.”
The CNC machine’s main benefit for Hyde, however, is accuracy.
“If you look at any stone done by hand, you see little ripples and dimples – and those things are supposed to be there, because it’s part of a handmade product,” he says. “If you look down an ogee edge made on a CNC, it’s perfectly straight. The quality difference is phenomenal.”
As a result, every ogee or radius job at HBF goes through the CNC. Hyde’s also experimented with other techniques, including etching; a profile of the horse’s-head logo for the Denver Broncos football team, for example, involved entering 250 coordinate points, but “it only took about an hour to do it.”

GOING 3-D
The unusual in CNC work is more the norm at Laser Spec Inc. in Calgary, Alberta. While the shop’s capable of doing standard stone fabrication, it’s becoming more-cost-effective – and profitable – to use different types of CNC production and look at a variety of products.
Instead of the usual from-the-slab granite, for example, the company works extensively with a harder grade of soapstone with its CamTech equipment.
“We do a lot of custom fireplaces and flooring and decorative items, like a carved lion’s head, from it,” says Laser Spec’s Yves Matson. “The soapstone’s on the upper end of what our routers can handle without going to diamond bits and water-cooled production.”
Laser Spec also works with some native stone from the Albertan countryside that’s used by a local carving artist, Matson says. It’s for authorized reproduction of his work, he adds, where “we get 80 percent of a carving done, and then he does the finishing touches.”
Using the CNC to carve in relief – Laser Spec also products a good share of molds for casting and prototyping – comes with a production technique that isn’t usually found in a stone shop: 3-D scanning. Matson explains that the CNC actually becomes a scanner with a 70” X 100” work area; a scanning piece is connected to the machine’s tool head, and light is used to determine vertical depths for shaping a Z-axis toolpath.
“We also use this for interior decorating,” Matson says. “Someone brings us a molding or decorative piece – a coat of arms, for example – and we can scan a tool path and router it out.”
The laser part of Laser Spec’s name comes from using a CamTech CNC as an etcher. It’s also where the company works in harder materials such as granite – but in 12” X 12” tiles for decoratives, such as plaques, commemoratives and some funeral memorials, often with photo-realistic replications.
Matson notes that, for this June’s G8 economic summit held near Calgary in the Albertan resort of Kananaskis, Laser Spec used the laser-based CNC to etch several thousand commemorative plaques for participating security services. The company’s also worked with local wildlife artist Gail Adams to reproduce her work on granite tiles for floor murals.
Much of what Laser Spec ends up doing with CNC wouldn’t fit the workflow of most fabricators concentrating on countertops — and that suits the company fine.
“We’re driven by what market share we can gain here with different products we offer,” Matson says. “It’s all about proving what we can do.”

THE LONG WAY
At Tri-State Cut Stone Co. in Frankfort, Ill., it’s not so much the intent to gain share; it’s in keeping the workflow sane as Chicago-area builders push through plenty of projects during good weather months.
“In the fall it would be chaos,” says Tri-State’s Keith Molenhouse. “We used to cringe when someone would want a window, for example; that’s hand-cut, and our handcutters would be out doing commercial jobs. We were probably losing a lot of work.”
Tri-State’s not the average shop cranking out the kitchens; it runs two Park Industries INFINITY CNC industrial profilers on a 72’ track. If it’s big – and likely a large limestone architectural project – Tri-State’s putting it on the machine.
One large challenge with tremendous volume capacity is, as Molenhouse says, “to think a little differently. When you have a 72’ table, you can saw a 72’-long piece of stone one way, and then turn around and saw back the other way. All of a sudden, you’re looking in terms of 24-hour days of production instead of eight.”
Keeping the CNCs running on a 24/7 basis became commonplace (the machines are monitored by an automatic alarm system), but breaking away from the “big saw” concept took a bit longer.
“In the beginning, we weren’t comfortable with some of the routering applications, and we were sawing 80 percent of the time,” Molenhouse says. “Now, we’re routering 80 percent of the time.”
Not all of that routering is detail work, either. Molenhouse notes that he can buy Indiana limestone in roughback slabs, and use the CNC to smooth the unsawn side.
“I can save four to five bucks a cubic foot,” he says, “and that works out, especially when buying 60,000 cubic feet.”
Where the big machines make a difference is, not surprisingly, in volume jobs, where a little bit work literally goes a long way. For a recent job of limestone balustrade along Chicago’s famed Wacker Drive, for instance, the pieces – of varying thickness – needed custom holes drilled in a job calling for handwork. The CNC did exact placement and depth for every hole – all 8,000-plus of them.
The CNC also worked well with volume at a school recently, where 70 pieces had two radius heads – a six-inch and a four-inch to give the work depth – that architects noted would need to be done in two pieces.
“We went to the masons and showed them that, with the CNC, we could do them in one,” Molenhouse says. “The masons realized we’d just halved their settings. Now, they call and tell me about jobs coming in that are perfect for the machine, and they want to team up and get me in on the work.”

TOOLING UP
CNC workstations aren’t the magic solution to everyone’s shop workflow, however; while the machines can do wonders with stone, it’s not a plug-and-play situation, either.
Going from rough stone to finished product on one machines needs a good understanding in job setup; while machines can store plenty of preprogrammed patterns and other production information, getting the right instructions to handle stone correctly can be a steep learning curve.
Or, as HBF’s Hyde says, “as hard as it is, stone is amazing fragile when you hit it in the wrong place.”
At Marble Tech Fabrication Inc. in Barrington, Ill., Joe Connally had a head start on this when his first U.S. Granite Machinery CNC – a Magnum – showed up two years ago.
“We had an oscillating cutting machine, based on CNC, doing point-to-point cutting,” he says. “We knew about certain materials and how they would react to the bit and its rpm. There’s a learning curve involved with any machine.”
Marble Tech now uses two Magnums, with almost all the work going to residential installations. Connally notes the machines’ biggest asset is job consistency, but there’s a major area that often gets overlooked – at least until a CNC finally gets installed in a shop.
“You’re only limited by the tooling, and you’re not truly limited because you can have just about any shape made for what you want,” he says. “However, tooling is probably a larger learning curve than the machine itself … I think it’s the least-educated part of our business right now, because the technology’s still fairly new.”
And, there’s also the human factor with CNC. You can bring all the technology you want into a shop, but will it replace experienced workers? And will they accept something that tries to do it all?
“In a high-volume shop, there are really two avenues you can try,” Connally says. “You can go high labor, or you can go automation. I think we’re a cross between the two; we still have a lot of manual labor involved, but much less because of inline polishing and our CNC.”
“A lot of the guys here think it’s really cool,” says Tri-State’s Molenhouse of his company’s CNC setup. “They see what it can do, and I tell them it’s good job security because it gets us work; we’re up again precasters where cost and time is a factor.
“Let me put it this way: Since going with the CNC, we’ve grown as a company, but we haven’t added anybody – and we haven’t had mass firings, either.”

This article first appeared in the September 2002 print edition of Stone Business. ©2002 Western Business Media Inc.