February 2008 Edition

WATERJET

Waterjet to the Rescue

When a fire truck fell victim to a fire, a waterjet used by the truck's manufacturer was able to salvage it as well as increase efficiency and save rebuilding costs

After responding to a fire in Galesburg, IL, a custom-made fire truck from Alexis Fire Equipment Co. needed rescuing when a wall collapsed on it. At first it was given up as "dead," but thanks to waterjet technology, it was resurrected.

"In order to get access to water, the firefighters parked the truck close to the building, and during the fire the building's wall collapsed," Mike Shull, Alexis vice president, said. "Fire engulfed the aerial truck, incinerating everything on the driver's side. The warning lights, the console, all the plastic components were melted."

Once the vehicle was returned to the plant in Alexis, IL, the fire equipment manufacturer was tasked with rebuilding the fire truck. In the past, a rebuild would not have been worth the time or the effort, given the heat-affected zones created by the machining methods Alexis previously used. But, with the company's Omax 80160 JetMachining Center, it was a different story.

A Three Month Rebirth

"Basically, we rebuilt the vehicle from scratch," Shull said. "It took us about three months, because of the testing that had to be done, particularly on the aerial device, given the amount of heat it took."

Since 1947, Alexis has specialized in building custom emergency equipment for fire departments, including pumpers, rescue units, tankers, aerial rigs, as well as specialty vehicles like ATV incident response units, dive team vehicles, and command centers.

Initially established as a family business, the company delivers about 75 vehicles each year to fire departments throughout the Midwest.

According to Shull, the waterjet has been central to Alexis' manufacturing process since its purchase. It's used to build a wide range of emergency vehicle components.

"We use it to make almost all the body skins, wheel wells, control panels, custom cab consoles, and pump mounting brackets. The brackets were cut out of half-inch thick steel," Shull said.

Prior to the waterjet, Alexis machined components with a CNC plasma cutter.

"With high-temperature plasma, we battled heat distortion," Shull said.

In order to mitigate the warping effects of plasma heating, Shull and team rigged the plasma cutter with homemade water misters.

"We put air and water on the assembly and would manually turn on the spray nozzle while cutting to dissipate the heat," he said. "The other thing we tried to do was cut many parts with a heat sink."

Both solutions, though ingenious, only were effective marginally. Shull knew the company couldn't rely on the water misters indefinitely. So, as the plasma cutter began to age, he investigated alternatives.

Cutting Out a Fire Truck

After visiting IMTS in Chicago, Alexis was introduced to Omax by Tristate Machinery, Inc., Wheeling, IL, an Omax distributor.

"We sent materials up to the facility and watched them cut out a fire truck for us," Shull said. "After we got the 80160 waterjet we realized how much better we could build a fire truck."

Setting up the Omax and getting his operators trained on it was easy, he said.

"We purchased the machine on Friday and we were cutting parts by Monday."

Because the waterjet did not produce heat-affected zones, it was a boon to Alexis' production process.

"The majority of our parts are aluminum – I'd say 80 percent," Shull said. "The rest are steel sub-frame parts and some stainless steel. Plasma warps due to heating and parts did not hold tolerances. The waterjet is more precise. There are parts we couldn't cut and form and stay within tolerance because of heat distortion, now we can. We especially like the waterjet's performance on smaller fastener holes."

Now, Nearly All In-house

Shull said he estimates that they were previously able to fabricate 50 to 60 percent of the whole truck. Now, up to 95 percent of the truck can be machined using the waterjet.

Unlike larger manufacturers, Alexis prides itself on the ability to completely customize each vehicle ordered by a fire department.

"Each fire department has its own specific equipment requirements," Shull said. "That's where the waterjet really helps. Because it's so much easier in the setup, the Omax lets us go from aluminum, to steel, to plastic. We don't have to change gases, consumables, or anything else. We just go."

The waterjet's speed contributed to Alexis' reputation for customization and service.

Shull said his company has to be flexible.

"The waterjet makes custom work easier to deliver. It cuts down on time to deliver the finished part – not to mention the amount of mistakes that can occur."

With the waterjet, Alexis has realized close to a 40 percent time savings in fabricating a truck compared to previous machine tool methods the company used.

Alexis has also been able to speed up its return-on-investment by providing waterjet services to other job shops.

"We make parts for companies in the fire service industry. We also do lots of stainless parts for nearby machine shops. We originally bought the waterjet for vehicle bodies but since we have some excess capacity, we also do jobs for other shops, so we get more usage out of waterjet," Shull said.

For its core emergency service vehicle business, Shull said that it's all about the waterjet's ability to deliver whatever the customer wants.

"The misconception is that customers walk in off the street and pick a fire truck off the shelf. The reality is that every fire department has its own way of doing certain things. It may want rollup doors instead of hinged doors, or a different number of valve controls. Almost every option is determined by the fire department with which we're working. For us, everything starts with a drawing, and then the majority of the production runs through the waterjet," he said. Omax Corp.

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