Versatility and Fast Setup
Features Create a
Transfer Press Cell that
Wins Quick-Turnaround
Stamping Work for
Shiloh Industries

Contract stampers are typically in the business of reacting quickly. Given today's constantly evolving production schedules and lean resources, the ability to swiftly and efficiently change back and forth between different part runs (for JIT, changing production priorities, etc) is an important attribute. But beyond the ability to juggle existing (and previously run) part numbers, there's the challenge of being able to quickly set up for a part you've never run before. On a transfer press, initial setup involves die preparation, of course, but streamlining the whole process also means fast press programming (including transfer motions), being able to quickly configure and try-out transfer finger tooling (that moves the parts from die to die), and setup of coil feed equipment.

Last Minute Orders

Being a seasoned contract stamper, Paul Beaton of Shiloh Industries (Dickson, TN) can verify the advantages. "We'll get a call on a Friday from a manufacturer whose press has suddenly broken down, and they need to hire out the production, fast. Other contract stampers have to allow weeks before they could start helping them out, because of long lead times for setup and because they aren't flexible enough to interrupt what they're doing. We'll bring the dies in over the weekend, tool up the transfer automation, program the cell, and start running parts for them on Monday. We've done it several times. This gives us a tremendous edge in terms of winning new customers."

Given the complexity of a transfer press, transfer dies, and related tooling, this sounds like a daunting task. Beaton explains that production teamwork is critical. Die drawings or photos will be faxed or emailed over from the customer while the dies are being shipped to Shiloh, so elements such as subplates (the standardized "tool holders" for dies) can be prepped ahead of time. T-slots in the bolsters will be modified if needed.

A versatile stamping press, with reliable automation and easy-to-program controls, is crucial to this capability. "Our newest stamping cell at the Dickson facility excels in all of these areas," Beaton adds. With 15 manufacturing plants located in four Midwest states and in Mexico, Cleveland-based Shiloh Industries is a major supplier of fabricated components for automotive seating and interior structural applications. Customers include Nissan, Johnson Controls, Visteon, Saturn, Toyota, ArvinMeritor, Ford and others.

Combination Link Press Delivers More Parts Per Hour

At the Dickson facility (formerly an A.G. Simpson plant), operations are split about 50-50 between stamping (including four transfer presses) and assembly operations, some of which are performed by multi-robot welding cells. In 2001, the latest in transfer press technology was leveraged by bringing a stamping cell on-line that includes a 1000-ton Combination Link transfer press. Most parts run on the press involve draw work. Some parts, such as an under-the-hood shock tower, require a very deep draw of more than 5 inches.

Shiloh reports that the link action of the press gives them a 20% increase in strokes per minute on this type of work compared to an eccentric gear press. The link mechanism is set up so that the ram speed is much faster on the approach and on it's return back up to the top, with a 50% slow down in the forming part of the stroke (for better material flow and improved die life).

Fully Integrated Coil Feeding Line

The fully integrated coil feeding line, from Coe Press Equipment (Sterling Heights, MI), consists of a servo roll feed, threading table, power straightener, and a 50,000 # reel with traveling coil car. The line is provided with many features and auxiliary equipment that facilitate fast coil changeovers. The digital servo roll feed Model CPRF-560 has the capacity to process .125" x 60" wide MCRS stock. It is provided with features such as a heavy duty cabinet with +/- 6" passline adjustment, dual roll centering edge guides, and a high performance pilot release mechanism. An integral hydraulic crop shear station is provided with the servo feed to enhance the line's ability to make short runs and quick changeovers associated with JIT operations.

The power straightener Model CPPS-PO-305-60 is designed to process a wide range of material thicknesses and coil weights with close center 3.0" diameter breaker rolls combined with 5.0" diameter pinch rolls. The machine is powered by a 25 HP AC variable speed digital drive and outfitted with features such as double-row backup rollers, SIKO digital breaker roll readouts, a Trabon automatic lubrication system, and a Peeler / Threader / Hold Down station for hands free material threading.

The coil reel model CPR-PO-50060 has capacity to hold a single 50,000# x 60" wide coil. It is provided with a fail-safe drag brake system to maintain control of material clockspring in the event of a loss of air pressure or control power. Hydraulic powered expansion and threading systems are provided as standard on this series of Coe reels. A hydraulic traveling coil car with 24" of vertical lift is used to stage and change coils. With 24" of vertical lift the coil car is capable of loading partial coils as small as 30" in diameter. An Allen Bradley SLC series PLC is used for machine control functions.

Integrated Controls

The controls for the press and the coil line are integrated, so part production information that determines coil feeding parameters such as feed pitch, speeds, acceleration, timing and feed angles, is automatically sent from the press control to the Coe ServoMaster control. Hundreds of part "recipes" can be stored in these controllers, an obvious benefit for multi-customer, batch-run stamping. But these advanced controls, with their menu-driven formats, also help to reduce programming time during initial part setup. Tom Buchanan, controls engineer at Shiloh, explains: "The press control lets you program all parameters quickly the first time. Once your dies are proven out, the setting are memorized, and they are automatically setup the next time you recall the part recipe." Basic press settings such as counterbalance pressure, ram shut-height adjustment, and hydraulic overload settings do not have to be re-entered.

The Kanban Effect on Changeover Procedures

The benefits of Kanban have become a strategic advantage at Shiloh. With its focus on quick-response, cellular manufacturing and inventory control, Kanban is a way of life at the Dickson facility, and applicable concepts are imbedded within the roster of "best practices" at Shiloh and it's parent company, MTD. When you're squeezing unexpected production into an existing schedule, fast changeover with minimal downtime is the key to making it work.

"For Kanban to be successful, you need total confidence in your manufacturing process," says Paul Beaton. "Since we're running with minimal inventory, we select systems that are very dependable and flexible, with quick changeover capability. The new press cell meets all of the criteria." He notes that typical transfer presses take at least 30 to 40 minutes to change over. The new press cell, equipped with dual rolling bolsters and fast coil change capability, switches from one part to the next at a considerably faster rate.

Shiloh's yardstick on measuring press changeover time goes beyond the 'hit-to-hit" parameter used by many stampers. Called "continuous-to-continuous," their stopwatch doesn't stop until after a part from the new run has been gauged and verified, and the press has then run continuously…making good parts and without part transfer glitches…for two minutes.

Stored part programs and integrated controls, the rolling bolsters, and the quick-change coil line features all contribute to the minimized changeover downtime. But the teamwork is equally important. Shiloh uses the "pit stop" approach, where each member of the team has a single, well-defined task to accomplish simultaneously with others on the team. Dies are pre-staged on the spare bolster, and needed hands tools are stored at the press (shadow-boxed to verify that they are ready) along with checklists.

The Uptime Advantage

Thanks in part to the high uptime factors, Shiloh typically has open capacity on the press, allowing the company to take emergency and overflow jobs from other stampers and parts manufacturers. Paul Beaton summarizes, "this transfer press cell proved its productivity potential right from the start. It was producing parts even before it was fully installed. Delivery from the equipment suppliers was ahead of schedule, and we put the equipment to work immediately." Since then, high R&M (reliability and maintainability), fast initial part setup and fast changeover capabilities have proven to support triple-shift, round-the-clock production.

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