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Right-Sized Tooling for a Down-Sized Economy

By: George Keremedjiev

George Keremedjiev is president of Tecknow Education Services, Inc., Bozeman, MT; 406/587-4751, www.mfgadvice.com. George also writes the monthly Metalforming Electronics column for MetalForming magazine.

Wednesday, July 01, 2009
 
 
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Undaunted imagination tends to surface best during trying times. In the metalforming community, where many companies once thrived within an atmosphere of large-volume orders, companies must reinvent their processes to not only survive but also to grow in the current economic downturn. Several metalforming companies with whom I have worked are trying different approaches to this challenge.

One of the finest examples of a metalformer that has successfully revolutionized its shop-floor operations into a radically new way of metalforming and assembly is the Kimball Office plant in Post Falls, ID. Kimball Office management has agreed to share with Metal-Forming its approach to using tooling equipped with electronic sensors with the hope that, in some measure, it will help metalformers of all sizes to rethink their attitudes, perceptions, and expectations of tooling, presses and assembly operations.

To utilize the Chaku-Chaku process, machines are configured in a U-shape production cell
To utilize the Chaku-Chaku process, machines are configured in a U-shaped production cell located close to the point of use, to minimize part travel and operator distance. The production line is extremely flexible to accommodate changes in production volumes, by simply adding or removing operators from the production cell.

Application of Sensor-Based Mistake Proofing

Kimball Office, a business unit of Kimball International, designs and manufactures office furniture. Its facility in Post Falls has operated a sensor-based mistake-proofing program for stamping dies and fabrication tooling for several years, and the sensor program has grown from a one-person operation into a four-person team. Team responsibilities recently have morphed into a total rethinking of the fundamentals of metalforming and assembly. The plant uses electronic sensors to prevent die crashes, mistake-proof fabrication and assembly operations, and measure part quality.

Some time ago, Kimball set out to develop the ideal lean-manufacturing production line—one that produces what the customer orders only when the order is required, with minimal if any setup, short part-travel distances, negligible work in process and sensor-based mistake-proofing techniques that result in defect-free products. This ideal lean-manufacturing cell also should be flexible, to quickly accommodate changes in customer demand and enable profits to be made at low volumes.

Traditional large, expensive and setup-intensive stamping presses and their tooling do not lend themselves well to this approach. So, to convert its traditional die- and press-based metalforming into a lean-cell methodology, Kimball’s team underwent a total and unhindered rethinking of its metalforming and assembly processes. This first step is the most difficult of all, as it requires all participants to create a blank slate in their minds with which they then can reformulate and reconfigure their traditional dies, tooling, presses and assembly machines.

As a result, Kimball Office developed an inhouse capability to design, build and implement unique production equipment that applies the best of electronic sensors, automation and lean-manufacturing production cells to the metalforming environment. All shop-floor operations have been right-sized to better-reflect the economy.

Mapping Value Streams

Kimball Office began by developing detailed maps of its parts-manufacturing processes, flows and timing on the shop floor. This single, large and integrated value-stream map details all of the specific manufacturing steps, part-travel distances and the amount of time parts spend at each step.

To generate such a map, start at the incoming raw materials area of the factory and work your way to the final shipping point of the finished piece. The map must include drawings of all of the steps, distances and timings, done on a large sheet of paper. Skip nothing. Document on this map the complete travel agenda for a given part. Include the temporary storage of parts in bins, awaiting further processing.

The map should clearly define the total throughput for the manufacturing of each part. A good value-stream map also incorporates all of the

Tooling is angled to use gravity to help slide parts into position.
Tooling is angled (left) to use gravity to help slide parts into position. Each set of tooling is sensored to cycle the part automatically once the part slides into the proper orientation. Once the tooling has cycled, the part automatically ejects into the exit tray (right).
tooling and machinery required to manufacture the completed part. This includes all pressroom dies, including fabrication tooling and the discrete value-added steps such as welding, hardware assembly and inspection.

Explosion and Compression

After completing a highly detailed value-stream map, the metalformer then should mentally explode the entire process into its essential and discrete manufacturing elements; Kimball Office’s team analyzed each element within its place in the total picture. Free your mind to imagine piercing, forming, bending, staking, hardware insertion, welding, drilling, tapping, etc. into discrete and separate steps, and liberate those steps from the current dies, presses, tooling and machinery currently being used. This will allow you to restructure them with simpler tooling and machinery.

Tough questions must be asked, such as, “Could I combine this step on the value-stream map that occurs in the left side of the building with a completely different step that occurs several hundred feet away?” Or, “Could this hole being pierced on station six in a large progressive die be pierced in a smaller, simpler die that also might incorporate a bend currently being performed separately on a press brake 200 yards away?”

Hold back nothing. Ask all forms of creative questions during this process. You just might find that for a given part you do not really need a large and expensive 14-station progressive die and a 400-ton press, but rather a series of much simpler dies and machines. This is precisely what Kimball Office managed to do with one of its parts-manufacturing operations.

Chaku-Chaku

Roughly translated, the Japanese term “Chaku-Chaku” means “load-load,” but in the manufacturing environment it refers to a single-piece manufacturing process in which a worker takes a part from one workstation to the next—one worker, several tasks. He sets up and operates each machine from the beginning to the end of the production cycle. This concept is at the core of the Kimball Office philosophy of right-sized tooling and machinery, and guided the company as it replaced a complex and expensive set of processes that once occupied thousands of square feet of plant space with a greatly simplified room-sized series of right-sized stand-alone machines and tooling.

Kimball arranged the machines and tooling in its new line sequentially so that one person can operate the entire line. The operator walks from machine to machine placing the part into the tooling and then removing the previously processed part and placing it into the next adjacent machine. The right-sized equipment processes the newly inserted part unattended while automatically unloading the previously processed part. This frees the operator to perform other activities while the part is being processed.

 

 
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Related Enterprise Zones: Presses, Sensing/Electronics, Tool & Die


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