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Job-shop FMS speeds vertical growth.

Goetz and Son, a German job shop located outside of Heidelberg, has 200 employees and yearly uses about 3000 tons of material, with thicknesses from 0.5 mm to 4 mm. Materials include stainless steel, aluminum, brass, and titanium.

Faced with an impending expansion involving a new $2.5-million building, the firm realized it could expand vertically. Goetz installed an automatic storage and retrieval system, automatic load and unload capabilities, vertical storage unit, and two Behrens turret punch presses in 1989.

As a result, the firm has nearly eliminated sheet-metal handling, and has expanded operations without the need to increase its work force. Instead of investing in a costly building program, Goetz invested one-third the amount in new equipment, and increased productivity, improved order handling, started untended weekend operations, and altered plant-floor use to cut congestion.

Brothers Rolf and Harry Goetz own and operate the business started by their father over 40 years ago. Harry, an engineer, is responsible for production and sales. Rolf oversees administrative operations. He also manages the shop floor and office data processing, and is responsible for the firm's automation efforts.

Flexible manufacturing system

The firm has been using Behrens turret punches for over 16 years. When Rolf and Harry Goetz took over the business, the firm used many different presses and punching machines. Soon the brothers converted to Behrens turret punch presses, purchasing the latest machines in 1989. Before that, in 1988, the Goetz plant had run out of space. More equipment was needed and a new building would seem the obvious solution for the space problem.

While looking at new turret punch presses, the brothers viewed a newly introduced arterial AS/RS (automatic storage and retrieval system) from Behrens. The concept of an FMS built around an AS/RS cell that constantly delivered material and removed parts made sense. Also, the floor space savings resulting from the AS/RS would be more than needed for two new presses.

Harry and Rolf Goetz looked further, at a vertical tool-storage system, and saw how to reclaim even more floor space. More importantly, these investments would also bring capabilities for good management and control--from order entry to product shipment. A concept of vertical growth evolved in their minds.

Pre-FMS material handling

Before installation of the FMS, material handling at Goetz was not only time consuming, but also a source of quality problems. At delivery, forklifts moved each pallet of sheet metal to the shears. There the pallets were unwrapped, cut to size, and then moved into storage. During handling the pallets were sometimes dropped, resulting in even more handling. Paged material was again conveyed from storage to the presses, requiring an average of 10 to 15 min each time. People waited for material while the shear worked; they waited while material was coming to the presses; and they waited because of plant-floor congestion.

Post-FMS material handling

Today, Goetz FMS design and layout solves the handling problem. Upon delivery to the plant, pallets of sheet metal are unloaded from trucks at an outside station, where pallets are also unwrapped. Next, a conveyor transfers the pallets directly to the shear for sizing, or to the vertical AS/RS elevator. This automatic storage system delivers material to a machine in 3 min; workers no longer stand around waiting for material.

"Savings were much higher than we expected, especially in the shearing area," says Harry Goetz. "Shearing itself requires little processing time; it's normally the manual material retrieval and dispersal times that limit productivity. Shop productivity increased once the AS/RS connected all machines."

In addition, some shearing was eliminated because of the automated material handling on the turret punch press and because of larger tables on the presses. A full-size loader processes sheets that previously required two men when loaded manually.

"The cumulative effect," says Mr Goetz, "is that today all shearing can be done on a single machine in one shift."

The ability to process larger sheets without manual handling resulted in further savings because of the expanded nesting capability. Overall, Harry Goetz points to three advantages stemming from the FMS installation:

* Control of every order from anywhere within the sheet-metal area.

* Automatic feedback for real-time control--keeping all machines busy.

* Constant on-line monitoring of raw material by the supplier.

Untended weekends

The capability to control shop planning on a real-time basis, combined with automated equipment, made Goetz even more ambitious. The job shop prepared to take the next logical step: untended operation.

During a typical work week, one operator attends the system's two turret punch presses. However, on weekends Goetz planned for the fully automated machine to run untended. Raw material was brought automatically to the turret presses and the finished blanks returned into the AS/RS. After introducing small software changes to the system, the first attempt at untended operation was a success.

Before trying the untended run, Goetz determined how to handle one potential problem: how to get a "machine down" message to service personnel without having a supervisor on the shop floor. Engineers connected a telephone line to the machine, so any unplanned changes of machine condition would automatically initiate a call to a standby service person's home.

Rolf Goetz discussed some of the system's administrative benefits: "The order-tracking advantage comes from the fact that we can allocate orders to different, connected machines. From in the office or out on the plant floor, we know when a job or machine starts or finishes, because a machine won't have raw material unless we operate an elevator for it. The operator can't remove the finished workpiece unless he asks for it to be taken away."

Order-tracking ability

These computer-controlled actions, Harry Goetz points out, are actually signals that give them real-time control of the order status. "This is the reason we tied the AS/RS to the shear and punch presses, and why we added an additional input/output station that serves the press brakes. That results in our ability to track each order in real-time from the time we receive it until we allocate it to the press brakes."

Harry Goetz estimates that the vertical expansion saved over 245 sq m of floor space. While the firm prepared to convert to vertical sheet storage, it also decided to install a tool elevator next to the punch presses. This freed more floor space and relocated the tools closer to their place of use. The vertical tool storage system from Kardex Bellheimer Metalwerk in Germany has 48 trays capable of holding 500 tool, die, and stripper sets. At 120 sq m, the new AS/RS saves nearly 180 sq m of floor space once used for material storage. The new tool elevator takes less than 5 sq m compared to the old, 70-sq-m toolroom. "Not only have we reclaimed space, we have extra storage capacity in the new AS/RS. Congested aisles are no longer an issue. In the past, pallets often could not go back into storage and were left on the floor, in the aisles. Today, the AS/RS system also serves as interim storage and brings material directly to the bending machine," says Harry Goetz.

Because much between-process time and manual material transport has been eliminated, one shear is sufficient. In addition, many full-size sheets no longer must be precut, because the AS/RS supplies and retrieves them. Under the old arrangement, a single stored pallet may have been brought to and from the shears for cutting. Today it comes from receiving, may or may not be cut, and goes directly into the AS/RS.

The Behrens machines have larger tables and can handle longer sheets than the old system. The six-meter-high AS/RS is 27 m long. Another turret punch press and shear are on the opposite side of the AS/RS from the two new machines. This third punch will also connect to the AS/RS. In the future the finished blanks may be brought automatically to the bending machines." At that time," say Rolf Goetz, "all the presses, the shear, and the material handling will be automated."
COPYRIGHT 1991 Nelson Publishing
No portion of this article can be reproduced without the express written permission from the copyright holder.
Copyright 1991 Gale, Cengage Learning. All rights reserved.

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Title Annotation:flexible manufacturing system
Publication:Tooling & Production
Date:May 1, 1991
Previous Article:Grinding controls go CNC.
Next Article:The systems-integrator edge.

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