November 2007 Edition

SAWING

Building in Critical Cutting

An automotive supplier which had to meet both tight budget constraints and tolerances, turned away from pivot-head sawing to succeed

The automotive industry is a demanding customer, seeking higher quality at lower costs. Suppliers to the industry must find better ways of producing parts that not only maintain the quality demanded, but also do so at a profit.

Schuler Hydroforming, Inc., Canton, MI, faced such a problem with producing parts for a stainless steel automotive exhaust system.

The systems are constructed from several parts. An OEM approached Schuler for the manufacturer of an exhaust system with both tight target costs and tolerances. Craig Zeleji, company operations manager, knew traditional manufacturing methods wouldn't produce the tolerances as tight as 0.25mm and allow for a profit. He pulled together a team to produce a solution. Schuler's expertise is in the engineering and manufacture of metalforming systems, and produces components and parts, such as hydroformed stainless steel exhaust systems.

The Hydroforming Solution

Company engineers, Klaus Hertell and Prashant Soman, proposed hydroforming multiple parts from a single workpiece. Then, using a complex fixture, three simultaneous saw cuts would create four separate parts, all in the time former methods would take to finish a single part.

While Schuler engineers worked to develop the dies necessary to hydroform the workpiece, Zeleji surveyed cold sawing capabilities to determine which would be suitable. Even though cold saws were built for heavy-duty production work, he found the saws had pivoting heads like chop saws. The pivot would keep tolerances greater than those required by the customer.

Cycle time of just under one minute, which was within the Schuler requirement

After doing his homework, Zeleji contacted Jon Oak, vice president, Rock Tool & Machine, Plymouth, MI, for an evaluation of the pivot-head saw solution. After analysis, Oak called Jim Larson, president, Kalamazoo Machine Tool, Kalamazoo, MI, for an equipment recommendation.

Sliding Heads

Larson suggested the semi-automatic KMT Model 360 Vertical Column cold saw. The KMT saw heads slide in a machined dovetail in a heavy-duty column. The vertical column construction provides saw frame guidance and stability, with vibration-free sawing to maintain tolerances to within those required by Schuler's customer. KMT supplied Rock Tool & Machine with flat-base columns to be attached to the fixture.

Rock Tool designed the base to hold Schuler's hyrdoformed workpiece and provide a platform for the three KMT saws. Since the workpiece had a number of angles, each column had to be positioned so its saw head would make contact perpendicular to the workpiece, creating a circular, instead of oblate, cut.

With the help of the Schuler team, Rock Tool designed a fixture that positioned the left and right columns at a 5° angle so the saw heads could cut though the cross section of the workpiece correctly.

One Minute Managed

The center saw head and column were mounted at 90° as the section of the workpiece at that point of encounter, was horizontal. Timing of all three saws was critical. To ensure that all three blades made contact at the same time, Rock Tool developed a control system with a one-button initiation.

The initial setup resulted in a cycle time of just under one minute, which was within the Schuler requirement. Because the shop runs the parts in batches, the company can experiment with various parameters to further improve productivity. Kalamazoo Machine Tool

Visit www.rsleads.com/711mn-207 for more information

What do you think?
Will the information in this article increase efficiency or save time, money, or effort? Let us know by e-mail from our website at www.ModernApplicationsNews.com or e-mail the editor at pnofel@nelsonpub.com.