Cotterman Co. adds sawing automation to achieve made-to-order production

July/August 2011 - “Our goal is to give our customers a ‘no-wait’ experience,” says Rob Stimpson, project manager for Cotterman Co., Croswell, Mich. The company, which has produced rolling warehouse ladders since 1925, adopted a business plan that allows it to produce small lots rapidly and cost effectively. But first the company had to find a way to reduce inventory and achieve faster setup times to support a made-to-order process.

Cotterman got its start in a small Chicago-based plant. Today, the company operates four manufacturing locations in California, Georgia, Michigan and Texas and is the market-share leader in rolling warehouse ladders. The company also makes steel, special purpose, office, track and fixed ladders and work platforms. Marquee retailers and national MRO distributors specify its products, and they are used in industrial, commercial, government and military applications.

“In an operation like ours, we maintain 6,000 finished-goods SKUs with variations as subtle as tread type,” says Stimpson. “On any given day, we have a range of different-size tube lengths to cut. We would run large batches and store a sizeable inventory of cut and bent parts because machine setup was so time consuming and challenging.”

The company used a tape measure to establish hard stops when cutting tube lengths. In addition to long setup times, the manufacturer tended to generate more scrap because the pressure of the steel pushing against the hard stop made it difficult to maintain accurate part lengths. Working to move to a made-to-order process, Cotterman implemented an interim technology step but found setup time squandered the gains the company made in inventory reduction.

“We were at an equipment show and saw the TigerStop automatic stop-gauge and pusher system being used in combination with a Scotchman cut-off saw,” says Stimpson. “It was a total solution that addressed all of our problems. We met a vendor but left the show with a company willing to partner with us to integrate the TigerStop technology into our production processes.”

TigerStop LLC, Vancouver, Wash., designs and builds stop-gauge and pusher systems, ancillary support products and software. Rooted in manufacturing, the company works closely with metalworking, plastics, furniture and cabinet customers around the globe.

Small lots, fast response
Cotterman engineered a custom feeder for the machine and took delivery of its first TigerStop system in 2009. “The ability to produce small lots quickly is a fundamental advantage that U.S. manufacturers like Cotterman are using to gain a competitive edge in the international marketplace on the basis of quality and timely delivery,” says Matt Harris, chief marketing officer for TigerStop. “Countries like China have less control over batch size, lead time and shipping. It’s a volatile economy, but the trend across multiple industries is that when customers need product, they want it quickly.”

Accurate to 0.004 in., the linear measuring and positioning tool is easy to set up and takes minutes for operators to learn. The manufacturer primarily runs recycled hot-rolled, pickled and oiled steel, 16-gauge tubing as well as some cold steel. A large cradle holds the steel tubing, feeding two pieces of material up to 288 in. long onto the table for cutting and other processes like notching. Long setup times have been reduced to seconds. The operator programs the TigerStop for part dimensions and pushes a button, allowing the machine to take control of the job.

“Ladders tend to be unplanned purchases requiring immediate fulfillment,” says Stimpson. In addition to supporting made-to-order products, the TigerStop has allowed the manufacturer to create manufacturing cells that eliminate batch processing. By integrating a TigerStop with its sawing operation and bending machine, Cotterman can create a two-process or more cell to perform jobs like hole-punching that used to be done further downstream.

“Because TigerStop literally does the cutting work for us, the machine frees the operator to perform other tasks,” says Stimpson. “This means we’re able to perform all operations at once instead of batch processing. The part is then ready to go to final assembly instead of requiring more processing.”

Eliminating inventory
During assembly, parts are welded, powder coated with low-energy cure powders and sent to the tagging area for labels. “We’re able to weld, wash, dry and powder-cure a complete ladder in as little as two hours,” Stimpson says. “We’ve removed the stocking element from the equation. Because we can drop-ship in two days through national distribution channels, our distributors no longer have to warehouse items.”

Ranked at more than 99 percent for on-time deliveries by one of its major distributors, Cotterman has received multiple awards for top vendor performance in on-time shipping and transactional accuracy. “That means we are shipping the right product quickly, the first step to rapid fulfillment,” Stimpson adds. “Our regional plants also enhance our ability to provide customers with products more quickly while reducing transportation costs and minimizing the likelihood of freight damage.”

With TigerStop, Cotterman has cut its amount of inventoried steel in half but increased its throughput by 50 percent. “We’ve also enjoyed a labor savings of 50 percent,” says Stimpson. “Incorporating the stop-gauge and pusher system has allowed us to take on additional work yet reduce the amount of time those jobs take. Employees can actually complete jobs taking us much closer to the downstream product. Our goal is take on more business, not operate with less employees.”

The manufacturer currently is outfitting a major retail chain with its rolling dual-track ladder. The stores have between 20 and 50 aisles of light-duty racking to hold inventory in aisles about 3 ft. apart. Rather than facing a shelf like a conventional ladder, the rolling dual-track ladder runs between the shelves, allowing employees to reach both sides at once. A patented gas-stop feature allows an individual to pull a cable and flip the ladder out of the way when not in use.

“The track system rolls on electro-galvanized tubing,” says Stimpson. “We have to cut large amounts of this tubing at a tolerance of ± 0.03 in. We were not able to achieve this tolerance with a traditional band saw and hard stop. Typically, the material weight bumps the hard stop, and half the batch is accurate and half is running too long. With the TigerStop, we package steel-banded 19-piece bundles as they come off the saw. The line runs 12 hours a day constantly cutting tube. We could not have done this job before.” The manufacturer is supplying 30 ladders each to 800 stores in the retailer’s chain.

Cotterman is using less floor space, maintaining one to two days worth of sub-assembly inventory to handle large orders. The company no longer maintains a finished goods inventory. “We’ve cut a substantial amount of waste from our processes,” Stimpson says. As a customer-driven company, Cotterman continues to focus on pushing fast delivery. “We are always evaluating our processes to see how things are working and to identify areas where we can make improvements. Equipment like the TigerStop system is a huge value-add for us.”

Cotterman is using two TigerStop systems on its saw operations and one on its bending machine at its Michigan facility. Each of the manufacturer’s branches also has TigerStop saw operations, totaling six in use. Cotterman plans to add the automatic stop-gauge and pusher system to its bending operations in Georgia, Texas and California.

“Companies like Cotterman illustrate how this type of automation can be added relatively quickly and easily to existing machine processes to dramatically change a plant’s productivity levels,” says Harris. “We feel the trend to low-cost automation is here to stay, and Cotterman clearly demonstrates how its implementation can result in meaningful business results.” FFJ

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