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Component Manufacturing dverti$er
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Don’t Forget! You Saw it in the
August 2018 #10229 Page #40
The Power of SMED and 5S By Keith Parker Structural Building Components Industry Professional
# 1 in our Lean Tools and Methods article series
Certified Lean Practitioner
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s a follow up to our 9-part “Ready for Change” article series, our next step down the “Lean” path is to introduce other tools and methods to reduce waste and time. The first in this new bi-monthly series focuses on SMED, Single Minute Exchange of Die, and how this process integrates with the 5S process.
In the distant past, a typical truss company fabricated 3 basic truss types. A common truss—depending on the load and span, a Queen, Fink, Warren, or Modified Queen—a gable end, and a scissor truss. These truss types typically possessed a standard heel, 24-0” overhang, and pitches of 4, 5, or 6/12. A skilled assembler (a layout man) using a tape, marker, and blocking would build a jig, define the span, set the location of the peak center, overall height, and tail length. In a given shift, 3 to 5 jigs might be set and the time it would take to construct the templates for a given truss could be as much as 20 to 60 minutes. After the jig was set, tens to hundreds of this truss were built. That was then—a high-volume, low mix market—however, today is very different.
At the Porsche plant in Stuttgart, Germany, robots assemble and weld the car frames, but the more intricate parts (i.e., engines and transmissions) are still fabricated by hand at a bench. All the pneumatic and air tools are suspended above the bench and within easy reach of the technicians. Hand tools are sorted and arranged, clipped to the bench in specific placement spots. All parts and materials are delivered to the bench by a robotic conveyor. Each piece is delivered in sequenced order and automatically arrives just-in-time based on the technician’s personal history of assembly time. At the bench, the operator has controls to speed up, pause, interrupt, and return defective parts, never having to walk away from the bench.
Today, the fabrication of roof trusses is a low-volume, high mix process. On average, 2 to 3+ trusses are built per jig and 30 to 70+ jig setups occur per shift.
Case Study: If the truss station is setting up 32 jigs per shift at an average of 2 trusses per jig and 60 bd.’ per truss, that line is producing 3,840 bd.’ That equates to 4 setups per hour. How can a plant set up and build more per shift? The goal is to increase the number of setups to 40, reduce the time of each setup by 5 to 10 minutes, and enable 4,800 bd.’ of production. Continued next page
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