May 2005

Technology Pays Off for Lexington Mfg.

This Minneapolis-based company looks to computer systems to help it ship most of its orders within 24 hours and to maintain tight tolerances.

By J.D. Piland
Lexington Mfg. Inc.

Minneapolis, MN

Incorporated in 1981, Lexington Manufacturing has grown to operate a 63,000-square-foot plant in Minneapolis, a 51,000-square-foot plant in Coon Rapids, MN, and a 150,000-square-foot factory in Brainerd, MN. The Coon Rapids plant primarily manufactures profile-wrapped window and door components while the Brainerd factory produces architectural flush door products. Lexington employs 140 employees among the three facilities.

Three Keys

1. Maintain visual and written communications with all employees of the plant.

2. Assure tolerances are as tight as possible by controlling the process variation within a 1.33 CPK.

3. Build relationships with customers that are based on manufacturing products to their specific demands.

In a few short weeks, Lexington Manufacturing Inc. will be in the throes of its busy season, manufacturing profile-wrapped components for windows, doors and furniture - to name a few.

Several years ago, this prospect might have intimidated the Minneapolis-based OEM supplier. Not anymore, especially since 90 percent of the shipments at the company's 61,000-square-foot plant in Coon Rapids, MN, are sent out within 24 hours of the initial order.

A fixture in the WOOD 100 Report, with its first appearance coming in 1990, Lexington has grown from $1.4 million in sales in 1988 to projecting $47 million this year. It has been able to get to this point not only by adopting the principles of lean manufacturing, but also by implementing what President Bob Dimke calls "technology integration."

Lexington's technology integration encompasses everything from the way employees communicate with each other to quality control using mean centering concepts (see Mean Centering sidebar).

Lexington has even networked all its computer stations to servers located in Coon Rapids and Brainerd, MN, where the company operates a 150,000-square-foot factory. The Brainerd facility primarily produces laminate and fire-rated door stiles for the architectural flush door market.

While Lexington Manufacturing is now integrated to the gills with technological advancements in the wood industry, it was not always that way.

The Beginning

Incorporated in 1981, Lexington bought out a trophy-and-plaque-making company in 1984. Along with it came a now-23-year-old Heian CNC router, which is still in use every day at Lexington's Coon Rapids plant.

Lexington Mfg.'s Coon Rapids, MN, plant primarily produces components, most of which are profile-wrapped, for a large window and door company.

"They had a line of plaques and trophy products, so that kind of gave us the foundation to say we are into CNC routing," Dimke says. "That was really the beginning of our dedication to the wood products industry."

Though Lexington continued producing trophy products for the next couple years, it became evident the Heian router could be used for much more than trophies.

In the 1980s, CNC routers were not as prevalent as they are now - and they certainly were not as user-friendly, Dimke notes. Woodworkers were intimidated by the prospect of a CNC router, so Dimke and his brother, John, who is now vice president of operations, pledged to become CNC router experts.

"We felt that if we became good at setting the machine up and programming, we could do a lot of work for people who didn't want to [buy a CNC router]," Bob Dimke says.

As Lexington achieved success with its router operations, the trophy business was dropped from its repertoire and components took over. Now Lexington produces components for windows and doors, bowling alleys, store fixtures and residential construction.

About 10 years - and four Shoda CNC routers - later, Dimke said, "This is good, but if we want to grow we have to keep up with technology and decide what we think will be popular and needed."

"Our answer was veneer," Dimke adds. "There were a lot of advancements in adhesives technologies, as well as the acceptance of composite materials."

Lexington chose profile wrapping to cash in on those advancements and to introduce itself to laminating and veneer experimentation, thinking it could offer its customers a cost-effective alternative to solid wood parts. Today, the company specializes in wrapping vinyl over wood, wood over vinyl, and, at times, wood veneers over other composite materials.

Lexington processes about 2 million lineal feet of profiles a month with its three Barber+ín profile wrappers, all located at the Coon Rapids plant.

An Evolution

With CNC routing and profile wrapping operations as the business' lifeline and orders growing by leaps and bounds, the company needed more-than-adequate computer systems that were capable of processing the customers' desired products.

A Lexington worker checks these cabinet components as they are fed through a Barber+ín profile wrapper, which is heating the wood for adhesive application.

As part of its business strategy, Dimke says the company makes a full commitment to its customers. In fact, Dimke notes, Lexington's mission statement is not to build products, but build relationships that build products. With that in mind, the Lexington crew set out to accommodate one of its biggest customers on whatever it wanted - namely a 24-hour turnaround.

This large customer, which Dimke was not at liberty to name, has a Lexington employee working onsite at its plant; Dimke calls this "vendor managed inventory."

In this approach, Lexington manages the customer's inventory, the employee communicates with the other Lexington employees and, in some instances, eliminates any face-to-face, customer-supplier interaction. The orders go right into Lexington's computer system, and then it releases an order to the shop floor. A cut bill is made, the operators fill that cut bill and the product ships the next day, Dimke says.

To meet the 24-hour deadline, Lexington has had to become a lean manufacturer and is working to continuously improve its operations to eventually achieve one-piece workflow.

The first step toward that goal came not from a technological breakthrough, but an occasional lapse in verbal communication.

Up until 1996, Dimke says the company ran three shifts and relied on verbal communication, which sometimes would go by the wayside as employees would fail to relay a message among the shifts. That year, Lexington switched to only first and third shifts, which meant all communications would have to be done on paper or through e-mails. Today, near the company's timeclock, employees refer to their written communication center, a hallway littered with progress charts and reports, safety instructions and employee photos, as "Info Alley."

Lexington Mfg. workers inspect the Weinig Hydromat 23C moulder as cabinet parts are fed out of it and toward a Barber+ín profile wrapper.

The new visual communication efforts virtually eliminate most verbal communication issues that might arise. To make it work, Lexington has made significant investments in new computer technologies.

"It was technology that allowed all of this to take place," Dimke says. "In our company, you'll see it time and again, in Info Alley, the e-mails, all the terminals and electronic integration on the shop floor. All of it has to do with communication."

Standardizing the Process

"Everything starts in the engineering office," Dimke says.

When Lexington receives a new or repeat order, the company puts the piece through a Q-spec, or quality specification. This includes anything from dimensions and quantity of the order to any other critical element the customer deems necessary, including packaging, Dimke says.

Diamond Ls and Diamond Cs are bits of information that are vital to a component, whether to the customer (C) or to Lexington (L). "Those are all standards that would be contained in the prints that are generated in our engineering department," Dimke adds.

Once the Q-spec is completed, if no drawing has been provided, Lexington's engineering department produces one in AutoCAD Release 14, on which all workers are trained to use and read.

"It's part of that standardization, one of the principles of lean," Dimke says. "Everybody in the plant can go department to department."

Mean Centering

Lexington Mfg. strives to keep its components in tight tolerances when coming off the production line.

It is able to do that by adjusting production procedures and equipment based on a 1.33 CPK (capability index).

This requires measuring the tightness of the tolerances of each job. For example, Engineering Manager Paul Schiebel says, if a part is specified at 10 inches long, the goal is to get a part measuring 10.000 inches. The clincher - and what Lexington shoots for - is that 10-inch part can be reproduced time and again.

For instance, an operator uses a digital caliper, which is connected to a Statistical Process Control (SPC) unit, to measure the width of a randomly chosen piece to the thousandth of an inch (.000). The SPC then plots those points.

Take, for example, a bell curve. If the points are near the peak, the piece is close to the average or Mean Center. When the points veer left or right of the peak, then the tolerance of the piece is off and machine adjustments need to be made.

By mean centering - assuring the points are close to center and achieving as close to 10.000 as possible - and controlling the process variation to within a 1.33 CPK, Lexington can achieve as high as 99.99 percent repeatability and accuracy. In other words, when process capability of 1.33 CPK is reached, less than one out of 10,000 parts will not measure exactly 10.000 inches.

Lexington currently is at 77 percent of its stated 1.33 CPK goals. President Bob Dimke and Schiebel say they hope the company can reach 85 percent by October of this year.

Engineering Manager Paul Schiebel says, "We store the document with revision control electronically, and, when it comes time to run that particular job, we will create a packet of material for production, which includes the job router, control plan sheet and the print. It defines all the critical measurements production needs to set up the equipment."

The dimensions that need to be checked on the CAD print will be identified by a Diamond C or Diamond L or a number on the control plan. The control plan will signify which measurement device is needed and how often to check that measurement. Once the measurement is taken, the data is stored in one of nine Statistical Process Control (SPC) workstations.

Technically Speaking

Lexington not only went lean with expansive technological improvements, but also has added some highly technical aspects to aid in quality control.

Lexington strives to meet a 1.33 CPK (capability index). This process of plotting product measurements shows a history of the machine's capabilities and performance (see Mean Centering Sidebar).

The 1.33 CPK is measured when an operator picks off a part from the production line. He measures it with an electronic caliper or a linear measuring device, which are both hardlined into the SPC. The SPC's Applied Stats software analyzes the data and plots the points.

"When those data points have some history behind them, you begin to understand where your process is possibly drifting out of control and where adjustments can be made," Schiebel says.

"During the run, we'll take those measurements and see how a machine is running based on the output of the product," Schiebel says. "With that information, we can drive our process to improve and make that equipment better, with less variation.

"Ultimately, what this does for our customers is allow us to squeeze a variation out of our products," Schiebel says. "Their products will create a better fit, which is a better product for the end user."

As of Wood & Wood Products' April visit, Lexington was at 77 percent of its 1.33 CPK goals. Through continuous improvements, it hopes to hit 85 percent by October, Dimke and Schiebel say.

Furthering the visual communications efforts, the SPCs have nearby progress report charts that indicate whether the day's work is ahead or behind schedule.

The SPC stations keep all employees connected to one another, as well. Any SPC station can access any job and any minute detail regardless of where in the shop it is located. They can do this because they all are - or soon will be - connected to the network servers in Brainerd and Coon Rapids.

"Knowing when your systems are in control, through the SPC, keeps us from producing bad products," Dimke says. "All of these things remove waste from the system, remove inventory, remove floor space requirements. Eventually, all of that trickles down to making you a more cost-competitive company."

And just in time for the busy season.


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