Programmable lubricant application accelerates stamper's die changes

Most stamping shops don't need more problems to solve, but many would welcome the opportunity to address the ones found at Red Rock Stamping Co. in Chandler, Ariz. During this volatile time in the automotive stamping industry, the company has had to cope with a steady increase in work over the last several years and now is faced with the real potential to double its business from this year to next.

This manufacturer of air bag and seat belt components says it owes its success to management vision, quality, a spit-and-polish operation, and close proximity to many of its customers' assembly plants in Mexico. Recently the company decided to look at ways to accelerate its lubricant application to keep pace with the growth.

Uncovering Spray Improvement Opportunities

Red Rock runs 18 to 20 different jobs per day in its presses during two eight-hour shifts. To keep up with this kind of transition, changeover has to be done in minutes, not hours. As a part of evaluating its die change process, the stamper evaluated its lubrication methods.

Facilities Manager Wayne Ziemann explained, "We were addressing all of the areas related to our die change process, which could last up to four hours. One of the issues that came to light was our lubrication process—factors were involved that we had not noticed before."

Red Rock's operators and maintenance team realized that a lot of cleanup was required around the machines as a result of lubrication on the stock. Also, too much lubricant remained on the finished parts - - an unexpected problem, because the lubricant was a vanishing fluid.

The stamper had been spraying lubricant onto the coil stock and into the dies using a system purchased to integrate with its presses. There didn't seem to be an immediate reason to abandon this method, as it handled the requirements well. In certain applications, lubricant was required only on the stock; in others, additional fluid was applied to specific die points to control heat and friction.

The spray was controlled by timers, which could be set and adjusted for the spray nozzles to cycle as the material passed through the press feeder. The existing system also collected excess lubricant as the stock was sprayed and recycled it, so the team felt it was making the most of its lubrication resource.

Gaining Control

UNIST Inc., Grand Rapids, Mich., recommended its SPR-2000 programmable lubrication station to Red Rock to help resolve its lubricant application problems. The system is designed so that the stamper has more control over the spray volumes and locations while continuing to use its spray and in-die lubrication methods. After testing the system for several weeks, the stamper purchased one for each of its presses.

The lubrication system consists of an electronic controller, a fluid supply tank, and a bank of valves that are electronically actuated according to input from the press line. It controls and delivers fluid and air to spray nozzles, die lubrication points, rollers, or any combination of the three. The key to the system, and the most important factor for Red Rock Stamping, is the level of control that can be achieved while maintaining ease of use.

The programmable logic control software is menu-driven and asks for some basic data from each job being run: material width, feed length per press stroke, and strokes per minute. This data controls spray frequency and duration. The controller stores up to 60 jobs.

The ability to apply parameters to each stamping job was another key factor for Red Rock. With its previous system, timers had to be reset for some new jobs, which contributed to longer die and job change times. If the timers were left at existing settings while the feed speeds and material widths changed, the result was excess fluid on the floor or parts, or not enough on the stock.

For most applications, the stamper creates a setup in the controller that actuates one spray per cycle. Five nozzles spray the material before it enters the die. Four remain stationary—two on each side—and one is placed directly over the metal, with adjustable position and angle. The number of nozzles for the application is determined beforehand and can be recalled quickly when the corresponding die and job are set up.

Valve duration is determined by the programmed setting and depends on the amount of material advancement and width. Spray patterns and widths are selected by changing nozzle tips. Red Rock uses a fan-shaped spray for the four stationary nozzles and a straight stream for the movable one. The air pressure behind the fluid also can be adjusted to alter the pattern of the spray when required.

Simplifying the Process Shortens Changeover

The programmable system allows the company to eliminate manual lubrication changes for each new job.

When a part is to run that has run previously, the operator recalls the corresponding setup from the preprogrammed information. The system then is ready to lubricate when signaled by the press or press control.

Die change time has been reduced from four hours to less than one hour. Although many improvements contributed to this, the fact that lubrication components no longer need to be handled for each job has been an important factor.

Today the stamper runs between 95,000 and 144,000 parts per day in its presses. With the company's current and anticipated growth, increasing volumes need to be handled smoothly, but it plans to add only one press for now. The lubrication system's ability to handle higher volumes without needing regular attention is increasingly important as the demands on existing resources rise.

Improving Housekeeping, Reducing Consumption

Excess fluid was one of the factors that caused the company to notice lubrication in the first place. In the die change process, daily operation typically involves paying attention to the results of overspray and inconsistent spray patterns and working out how to deal with the excess fluid. After implementing the new control system, which can apply the vanishing fluid in more carefully metered amounts, Red Rock found that most of the excess fluid was simply eliminated.

Currently the new application system has cut lubricant consumption by one-third. By taking time to set up the parameters for spraying fluid, Red Rock eliminated excess fluid on parts, machines, and floors. Programming the correct amounts for spray onto the coil has reduced the level of lubrication required in the die. While some dies contain permanent lubricant lines, most of the lubrication is done directly onto the coil strip, and the use of most die lines is eliminated.

Fluid purchase expenses have been cut more than 30 percent, and maintenance and housekeeping costs also have decreased. Excess fluid no longer travels to unwanted places, and cleanup around the machines and in the aisles is a fraction of what it formerly was.

Eliminating Disposal

Fluid disposal also has been eliminated. Only the necessary amount of lubricant is applied to the material. It is either completely consumed in the process or a thin film remains on the part. The presses are no longer set up to contain used fluid, so it is not necessary to clean sumps, filters, or basins. Some light periodic cleanup around the presses is all that is necessary.