June 2008 Edition

workholding

Making order out of ‘chaos’

Modular principle, multi-part clamping key to reducing operating costs

Through the use of flexible, multi-part clamping for complex parts, an Illinois operation has successfully produced a 21-hour machining cycle using only one manned shift. Also, the company priced out the manufacture of typical parts to China being machined in this new way and only the three-part order could be produced at a lower cost, without the shipping cost and time considered.

Solving complex part manufacturing requires three key elements, according to the workholding fixture manufacturer in this case, Triag. Advanced Machine & Engineering of Rockford, IL, builds the Triag brand of workholding devices in the United States.

Fixtures need to be flexible, modular and variable. To be flexible, the fixture must be suitable for various cutting conditions. It must also be adaptable to a wide assortment of materials, weights, sizes and configurations, whether used on a three-, four- or five-axis machining center.

Modular means the design principle of the fixture must be such that it allows the clamping devices to move and be repositioned on the fixture faces in different setups, often within the same job run.

Variable means the fixture must adapt to the particular machining center characteristics of mounting, access to the cutting theater and shuttling, with little or no modification.

The company, Profiform AG, is located in the town of Adligenswil, near Lucerne in Switzerland. Opened in 1987, the company began with vertical machining centers and simple clamping vises. In 2002, the first flexible manufacturing system was installed, allowing the first unmanned production to be accomplished. This resulted in immediate improvement in the overall productivity, as well as cost containment for the owners.

Currently, the heart of the operation’s FMS is a Mazak PFH 5800 four-axis HMC, with XYZ movement of 730mm x 730mm x 740mm. A 16-pallet rack, equipped with Tripoxy tombstones up to 960mm high, and 378-position toolchanger are onboard this formidable workhorse.

In the "chaotic" clamp setup, complete subassemblies are partially removed, ready for final assembly. Single large-part fixturing and/or the clamping of several small parts simultaneously are done. This chaotic clamping setup means constant change to the clamping location, which is performed by the Triag Powerclamp system. On more "organized" setup, the same part is clamped in all stations on the tombstone.

Typically, Profiform machines forged and cast parts, structurals, saw cuts, profiles and parts up to 400mm x 400mm x 50mm (15.75" x 15.75" x 1.97") in materials ranging from aluminum, stainless and tool steels to various plastics and composites.

For its clamping system, Profiform required process safety through rough milling, as well as the clamping of pressure-sensitive parts; maximum flexibility in terms of the clamping techniques employed; maximum clamp density for optimum space utilization; short setup times and ease of use. Triag responded with the modular Powerclamp design, consisting of a base rail, used as a support unit for the clamping modules, and the Microclamp fixture system for smaller parts, which runs on the same base rail design.

In a typical 21-hour running production day, only one shift of operators is required, during which all the worker know-how is brought to the task of efficiently scheduling and fixing the workpieces into place on the various stations, then programming the FMS to execute the runs. As a result of this system, 13-14 hours of unattended running time are translating into a decided competitive advantage for Profiform.

The company has priced out the production of various finished products, in small, medium and large batch runs, to China and found only the small quantity was made at a lower cost, with no shipping cost or time factored. This scenario boosted the confidence of both the company and its customers in the value of this workholding system.

Triag USA

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