LMI exercises control in growing custom mixing industry

CAMBRIDGE, Ohio—For the growing LMI Custom Mixing L.L.C., the process is all about control—control of its formulas for rubber compounds, control of the climate in its facilities and control of its supply line for its often time-sensitive products.

And the recent completion of $17 million in renovations over three phases at the southeastern Ohio plant only has increased that commitment to quality control, said Jim Nixon, general manager at LMI.

"There are not a lot of companies adding that kind of investment into custom mixing," Nixon said during a tour of the 140,000-sq.-ft. plant. "People are either taking capacity away and moving it to Mexico or idling production."

This is not the case at LMI, a joint venture established in 1998 that saw several iterations of ownership and divestment, and which now is owned by Lauren International (55 percent) and Meteor Elastomers Solutions GmbH (45 percent), Nixon said.

The $17 million investment added 60,000 square feet of office and manufacturing space to LMI's existing 80,000 square feet, with renovations taking place between 2015 and 2019. LMI also hopes to add 15 employees to its 105-person work force in the future, Nixon said.

About 18,000 square feet for product shipping and finished goods storage was added in 2015; about 28,000 square feet in raw materials warehouse space was constructed in 2016; and an ultra-modern, additional 12,000 square feet of "people space," as Nixon calls it, came in 2019. The latter encompasses a new fresh market snack bar; cafeteria and break room; locker room; and exercise and training rooms, all of which can improve morale, and, in turn, production.

"The expansion and investment were the direct result of increased demand from an expanding customer base," he said. "The LMI brand has been built around quality and service. Our growth and reputation in the industry support that."

But the piece de resistance for the investment—and certainly the upgrade that already is demonstrating the greatest return—was the addition of a third, $7.2 million mixing line in 2016. This brought LMI up to three fully operational mixing lines and has increased production capacity by 50 percent, Nixon said.

"Being able to say we were able to put in a new mixing line is something I'll never trade for anything," he said.

In 2019, LMI mixed more than 40 million pounds of rubber material, a "staggering output" for a firm of LMI's size, Nixon said, and the result of 15 consecutive years of increased output, by about 1 million pounds year over year. Total capacity at LMI currently is 60 million pounds.

"We leverage our capabilities, including our modern facility, equipment, manufacturing processes, control systems and technical expertise, to provide consistent quality of compounds that are often difficult if not impossible for our competition," Nixon said.

And it is that "consistent quality of compounds" that is a function of control.

"The entire controls system for the manufacturing process includes raw material receiving, perpetual inventory tracking, mixing controls, data collection and product shipping," Nixon said.

The new raw materials warehouse space and new finished product space both are completely climate controlled, allowing the raw materials to remain at a stable room temperature and the finished product—and the 105 employees at LMI—to remain cool on warm days.

The climate-controlled finished products space is crucial, Nixon said, as many of LMI's rubber products are time-sensitive for fabrication within a week or so.

As shipping time can cut into that time-to-fabricate, the cooler storage temperatures can extend the life of the product. In addition, customers are urged to use refrigerated trucks for transport.

"This is both a blessing and a curse in custom mixing," Nixon said. "All rubber compounds have a shelf life. On the positive side, that shelf life is used up for imports, which can take six to eight weeks.

"But we make quality stuff. Sometimes that means paying a bit more in shipping. The facility here in Cambridge is a very good location for shipping products across the country."

And with its still-populated-rather-than-automated chemical weigh stations, operators at LMI can precisely control the ingredients for a custom mix—whether a customer asks LMI to duplicate an outside formula, or whether LMI's chemical engineers need to derive the formula themselves.

"We like to develop the formulas, since then they become intellectual property," Nixon said. "But LMI is willing to serve any sized customer. We believe that small customers can become big customers if we help them grow."

And the ultimate goal for any custom mixer is to minimize variation, Nixon said.

"If you make vegetable soup, you use the same recipe—but the soup is never going to be exactly the same," he said. "This is batch control, where consistency and quality are paramount. The ability to support customers through efficient product development and precise control over a batch mixing process is going to continue to be very important in our industry."

Because the essence of LMI's charge is combining components for rubber formulation, excellent dispersion is key, Nixon said.

Good dispersion, according to LMI, provides consistency of properties within the same batch and between batches. It also creates a smooth and uniform surface appearance on finished parts.

Improper dispersion can lead to undesirable physical and mechanical properties, including imperfections in product appearance, reduced service life and poor part performance.

"Garbage in means garbage out," Nixon said.

Many factors influence dispersion, including the rubber formulation, raw material quality, raw material temperature and the types of raw materials used. Equipment age and mixing conditions—including time, temperature, pressure and rotor speed—also play a role in dispersion, according to LMI.

"Therefore, it is advantageous for a rubber compounder to have as much control as possible over the entire mixing process," LMI said on its website.

From raw material to finished product

"If you have five chefs making clam chowder, you're going to get five different versions of clam chowder," Nixon said. "All we want to do is leverage our experience and technical acumen to serve the customer."

And a customer may come to LMI with a request for either dense or sponge (foam) rubber—a specialty for LMI, which can be continuously extruded or molded—with a certain durometer and tensile strength, or perhaps in a specific color.

"All they want is a compound, not trade secrets," Nixon said.

And this is where LMI comes in, he said, whether the end use of the custom mix is a seal, belt, hose or bearing in the automotive, industrial goods, appliance, wire and cable, or agricultural industries.

And customers literally have thousands of raw materials from which to choose for the physical properties they are seeking. According to Nixon, traditional rubber fabricators see about 40 percent of their total costs go to raw materials, while custom mixers traditionally spend between 60 percent or 70 percent of their total costs on raw materials.

"And this is the artistic part of what we do," Nixon said. "This is where creativity and art meets chemistry, engineering and physics. That's what makes this fun."

In the case of a door seal, Nixon said, a customer likely would want a compound that is tough—but not too tough, so that it can flex—and resistant to the outside environment.

While some fillers like carbon black are added to the mixer via enormous silos, chemical fillers still are weighed and added by hand at LMI, which allows for "extremely customized solutions," Nixon said.

"We are trying to automate this at some point, but having a person here still gives us great flexibility," he said.

LMI uses mostly EPDM as its polymer, Nixon said, but can form compounds with numerous other polymers, including neoprene, NBR, NBR/PVC, SBR, polybutadiene, natural rubber, CPE, CSM, AEM and FKM.

Into the mixer then goes the polymer, an oil and the filler, such as carbon black or another pigment, curatives, processing agents or a flame retardant additive. Fillers also can be a mineral (clay or chalk), or a chemical (antioxidants or antiozonants).

These three foundational items form the rubber compound, which then is drawn through two separate mills at LMI before it is extruded into strips, cooled by fans and bathed in a stearate for shipping.

Because custom mixing can address more demanding product needs and performance, often with a lighter weight and lower overall cost, Nixon said he sees a trend of fabricators "leaning heavily on custom mixers for their expertise in compounding and mixing."

And for that reason, the industry, like LMI, should continue to grow.

"We still see an ongoing need for properties in certain applications that can only be achieved with the capabilities of rubber as the material," Nixon said. "And we have the utmost admiration and respect for competitors in our industry, as we share the same challenges.

"Competition forces you to improve. All of this benefits our customers and stakeholders."