Fabricator satisfies electrical enclosure standards and cuts costs with two lasers

December 2012 - At Nema Enclosures Manufacturing LLC, space is tight as the business grows. The company fabricates custom metal electrical enclosures from its 20,000-sq.-ft. facility on Houston’s east side. But limited floor space didn’t stop Nema Enclosures from adding a SuperTurbo-X Champion 510 laser cutter in early 2011 from Mazak Optonics, Elgin, Ill.

Soon after, Nema Enclosures’ president and owner Rob Bohn was already thinking of adding another laser. “By the end of 2011, it was clear that a single machine couldn’t keep up with the demand,” says Bohn.

In early 2012, the company installed a second STX Champion. To accommodate that unit, Nema Enclosures reduced its storage area for sheet production and tightened up its material ordering. It moved other equipment, and occasionally has to shift things around to access lesser-used machines. But it wasn’t all for nothing, as Nema Enclosures’ main product line generates the biggest demand for laser cutting. 

With its STX lasers, Nema Enclosures has improved its operation on multiple levels. In 2010, a surge of business pushed the company’s existing waterjet to capacity. To keep up with orders, Nema Enclosures outsourced its laser work to two separate local fabrication shops. 

“The cost of this outsourcing was high, in excess of $25,000 per month,” Bohn explains. “Plus, we were getting inconsistent deliveries and some quality issues.”

The company used drawings from its main product line to analyze which laser machine would deliver the best results. After evaluating its options with its distributor, Capital Machine, Tampa, Fla., Nema Enclosures determined Mazak’s STX Champion would be ideal.

Each machine is equipped with an automated load and unload cell, which optimizes the lasers’ throughput by feeding sheet for the next job as soon as the previous one is done. An operator sorts jobs based on material type and thickness then nests parts to get the highest yield from a single sheet. 

Once jobs are nested using Mazatrol Preview, Mazak’s CNC laser controller, the sheet is pulled and goes directly to the laser’s 5-ft. by 10-ft. bed. From there, it’s inspected and then sent for further processing including bending, hardware insertion and welding before powder coating and assembly.

Shifting work

Before Nema Enclosures bought its 1.3 kW STX Champion, it relied on a shear and waterjet to cut, notch, and slice parts to size. The process became costly and cumbersome, especially because of the waterjet. It cost Nema Enclosures about $90 per hour to run, including maintenance, consumables and replacement parts. In addition to maintenance downtime, the waterjet is slower than the laser.

“Everyone yawns and waits for it to cut,” Bohn says. 

Having the lasers has decreased the cost of operating the waterjet by about 30 percent. Now, Nema Enclosures uses its shear maybe three or four times per month, usually to cut plastic material to replace the waterjet’s bed. The waterjet is now used for nonmetallic items like Lexan, plastics or oversized parts.

Aside from costs, material throughput is faster and simpler. One customer, for example, specifies an enclosure that has parts made from 10, 12, 14 and 16 gauge material that are welded and bolted together four different ways. There are specifications for touch screen display cutouts, as well as a special latch so the customer can easily open the view window door and adjust the controls. In such a case, the vendor will ship the sheet metal stacked in reverse order of how Nema Enclosures would cut it.

“So we just slide the sheets onto the load/unload system, stage it, the operator hits the button and it starts cutting,” Bohn says. As soon as one laser is done cutting, the next sheet is immediately loaded. “That load/unload software is very sophisticated and smart. The laser doesn’t care—it’ll cut what we tell it to cut.”

Many of Mazak’s customers use a load/unload system to maximize the machine’s run time. Stand-alone machines typically run half the time during a shift, according to Marc Lobit, Mazak’s marketing manager.

“We’ve found that a machine with a load/unload runs about 75 percent of the time, so you have literally a 50 percent increase in throughput with load/unload,” he says.

Commonly used in production or job shop applications, the rugged STX Champion laser is the workhorse of Mazak’s 2-D laser machines. It weighs almost 28,000 lbs. and is offered in models with higher cutting power. The STX Champion’s mechanics make it a hybrid style CO2 machine.

The laser delivers a pivoting beam with minimal external optics, reducing power consumption in the beam delivery system and channeling more power to the torch, according to the company. Constant beam length ensures consistent cutting parameters regardless of the cutting head position across the sheet and table. This keeps the operator from having to tweak cutting parameters in different work table cutting positions. 

“This is a full-scale rugged machine tool. It’s very accurate,” Lobit says. “Some machines out there have two pallet changers and the head moves on an x-y axis up above the workpiece. In this case, the table moves in and out and the head moves across the gantry. It’s a design we’ve had for many years.”

Following standards

Nema Enclosures, which has no affiliation with the National Electrical Manufacturers Association, the trade organization that writes electrical enclosure standards, fabricates its products from cold-rolled and hot-rolled steel, 304 and 316 stainless from 10 gauge to 16 gauge thick. Its enclosures are used in industries such as chemical, transportation, wastewater treatment and energy. The company specializes in enclosures for lift stations, and it’s a supplier for Houston’s wastewater treatment Levels I and II.

The industries that use Nema Enclosures’ hardware require that it adheres to certain standards for holes, flanges, joint configurations and other rules for how they’re built regardless of size, according to Bohn. Those standards are administered by third-party certification companies, in this case, UL. The UL 508 standardizes industrial control equipment—panels, switches, motors and more.

The lasers’ ability to cut a range of material and thicknesses unhindered gives Nema Enclosures an edge over its competitors’ strategy of offering off-the shelf production enclosures with limited features. However, if Nema Enclosures cuts custom holes according to an OEM customer’s drawing, the rating responsibility transfers to the customer. 

For example, say the company is making cutouts for six push buttons, pilot lights, an emergency stop button and an Allen-Bradley touch screen PLC. Nema  Enclosures relies on the customer to provide the specifications so the openings comply with UL’s 4X environmental rating, which ensures enclosures are protected from elements including corrosion, rain and wind-blown dust. An OEM customer could run into trouble if it bought a production enclosure, then tried to punch, drill, saw or otherwise modify it. With the STX Champion laser, Nema  Enclosures can accurately make the cuts for its customer in any quantity.

“That’s been our entry to the marketplace and it’s given us lots of strength from a marketing perspective,” Bohn says. “With the laser, I can cut basically three enclosures of the same size for three different customers with three different hole configurations. It’s so fast, the cut time maybe goes up by 30 seconds or 1 minute total if I’m adding holes.”

Nema Enclosures is running the STX Champions 18 to 24 hours a day, five or six days a week as workloads fluctuate. Bohn says the hidden benefit of running the machines as fast as Nema Enclosures has is that Mazak jumps on top of maintenance when the laser hits certain hour benchmarks, much like the recommended mileage-based maintenance on a car. Mazak’s technicians not only come on-site to make adjustments, but also show the operators tricks to make the lasers run better.

“Every time the Mazak service technician comes to perform factory specified maintenance such as cleaning the resonator and calibrating it, they’ve always managed to spend another half day or so with my guys to conduct additional training, answer questions, etc.,” Bohn adds. “I don’t know about it until after the fact. Their technicians are really good, making sure our operators optimize the performance of the laser.” FFJ

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