When manufacturing and finishing processes work together nicely, you can call it efficiency, or in this case, the processes “gel,” literally. The infrared curing process implemented at this trailer manufacturer creates a powder coating gel finish that saves energy, room, money and space on a conveyor.

Edited by Lori Beckman

For East Texas Trailers (Petty, Texas), switching from liquid to powder coating eliminated weather condition worries, increased throughput and reduced overall finishing costs by 30% for the 17-year-old trailer manufacturer.

Although the new powder coating operation provided many benefits, the decision to implement a catalytic gas infrared (IR) oven as a complement to the curing power of the line proved to be the right choice. The company’s new 20-foot WolfRayet Galaxy IR oven offers a smaller footprint, a lower initial equipment investment, fewer burners, closer product spacing during color changes and a cleaner oven compared to an alternative convection oven concept.

“The more we looked into the curing options available to us, the more we realized that using gas catalytic IR oven technology as a pre-gel oven was a real contender, with some major advantages,” says John Peters, sales manager at East Texas Trailers.

East Texas Trailers’ finishing operation handles everything from main frames to ramps and fenders, and trailers ranging from 8 to 44 feet long. Every day, the company supports production of more than 30 trailers per shift.

Building a Powder Line for Higher Efficiency

East Texas Trailer produces more than 75 trailer models, from utility and dump trailers to tilt decks, livestock and pipe trailers, with hundreds of available options. Its finishing operation handles everything from main frames to ramps and fenders, and trailers ranging from 8 to 44 feet long. The company supports production of more than 30 trailers per shift.

So, when the manufacturer decided to transition from liquid paint to powder coating, designing the company's first powder line meant accommodating a variety of steel parts in high volumes.

First, the company considered a conventional convection curing system, which called for 220 feet of space. But when WolfRayet became a contender in the process, the oven manufacturer proposed only 20 feet of oven. That was when the trailer manufacturer realized it could build the curing system around existing production requirements, including the amount of metal processed per shift, conveyor speed and product mix. IR provides rapid energy transfer at the front of the process, while convection provides the additional time and thermal uniformity needed for large steel fabrications with varying geometries and masses.

The team settled on the final hybrid design, which consists of a 20-foot WolfRayet Galaxy gas catalytic IR oven used for pre-gel ahead of approximately 100-feet of convection cure oven. The IR oven rapidly initiates melt, flow and gel before the product enters the convection element, and the remaining thermal exposure completes the cure.

The decision to implement the IR technology eliminated roughly 100 feet of oven, two burners and more than $220,000 in equipment cost compared with the original convection-only concept.

“One of the major deciding factors was that the gas cat IR prevented us from having to overbuild our facility just to accommodate the traditional oven system, so construction costs were lower,” Peters said.

Benefits Beyond a Smaller Footprint

Positioning an IR oven at the beginning of the curing system, as East Texas Trailers did, stabilizes the coating first with a gel. The gel coating keeps the oven cleaner by reducing powder residue that can occur when fresh powder enters a high-airflow convection oven. Peters mentioned that the team was surprised how quickly the powder gelled in the IR oven.

The company’s color change process (it offers 20 stock colors) also benefits from the IR oven technology. Without a pre-gel step, more spacing between differently colored products might be needed to reduce the risk of loose-powder contamination. With the coating already gelled before it enters convection, however, it can run different colors much closer together. On a continuously moving finishing line, empty conveyor space equals lost production capacity.

“Being able to cure multiple colors without suffering from cross-contamination and colors mixing in the oven is a huge advantage for us in terms of throughput,” Peters said.

Energy savings is another advantage to the IR curing system. Unlike convection ovens, gas cat IR technology uses a flameless catalytic reaction to produce radiant energy that travels directly to exposed coating and substrate surfaces. That high rate of energy transfer at the beginning of the process enables a relatively short section of IR to accomplish a significant amount of the initial heating load.

The company’s curing system consists of a gas cat IR oven that completes a pre-gel process providing cost and energy savings as well as many other benefits.

According to Peters, the Galaxy IR system is user friendly. Startup and shutdown are quick and simple, and the system has required little day-to-day attention, he explained. The oven uses straightforward controls and recipe-based operation, enabling the trailer manufacturer to establish settings for its production requirements without operators having to manually configure the oven each time.

He added that the WolfRayet support team is excellent to work with.

For East Texas Trailers, adding IR enabled the curing process to complement the company’s existing manufacturing process. The result was a cure system with a small footprint, low upfront investment and a finishing line with the flexibility to keep up with a diverse color mix.

Lori Beckman is editor of PCT.