Architecture As Art

Finding the right process to emboss stainless steel exterior wall panels was a challenge that Todrin Laser Industries, Inc. (Taunton, MA) faced with its customer Della Valle Bernheimer, award-winning Manhattan architectural design firm.

Todrin's wall panel project was for an exquisite new residence masterfully designed by Della Valle Bernheimer (DVB) with a singular façade of glass and irregularly punched, stainless steel panels. The glass and steel combination animate the building by reflecting the changing light, the season and the vibrant New York surroundings.

The challenge for Todrin Industries was to emboss 36 in x 60 in stainless steel sheets with symmetrical rows of raised diamond shapes across the entire sheet surface. Top quality was paramount ? the finish had to show well with no surface scuffs or other abrasions in, on and around the rows of raised diamonds.

The sheets were supplied with protective PVC film covering which needed to be retained both during and after the embossing process for surface protection. This posed a potential problem for the embossing operations. Also, flatness of the embossed sheet was critical, both for appearance and structural integrity requirements. This flatness requirement was especially challenging because over 50 percent of the sheet surface required embossing with potential for major sheet distortion.

"We did quite a bit of experimenting before we settled on the final punching process," reported Dick Nichols, president of Todrin Laser Industries. "Our primary business focus has been as a laser job shop, but we were getting more requests to do CNC punching work, particularly for high end, decorative components used in residential construction. Among these were interior stainless steel wall panels, radiator covers and lighting enclosures. To do this punching, we recently bought out a small metal fabricator. When the DVB project came to us for proposal, we began running some tests on the Amada press we acquired and looked into special tooling needed to do the embossing work. The punching requirements were beyond the capabilities of the existing equipment so we looked at new."

Since Todrin's existing press was too small to handle the 36 in x 60 in panels, Nichols contacted Finn Power (Arlington Heights, IL) for recommendations. This was a "first of its kind" project and Todrin's customer needed to see actual stainless steel sheets embossed with the diamond shapes that met their requirements before going ahead with the project. Finn Power proposed doing a test run of parts on a new C5 Compact Express turret press. A custom embossing tool was needed for this test so Finn Power brought in Rick Maxwell, Mate Tool (Anoka, MN) sales engineer and Dennis Lowry, custom engineering manager for Mate.

"DVB's architects had established criteria for these embossed panels," reported Lowry, "but were unattainable exactly as they wanted the material manipulated. Mate recommended employing a Design For Manufacturing (DFM) process with Todrin and their customer to ensure a successful outcome. It was a challenge to design just the right forming tool which would create the correct balance of tension and compression on the sheet in order to generate really flat, nice looking finished panels with the right sized diamond shaped embossings."

Initially for the test, Lowry designed an Ultra Tec® tool to emboss 1-1/2 in x 2-3/4 in diamond shapes. The 36 in x 60 in sheet material used was .048 in 304 stainless with a #4 finish, the same material required for all of the completed wall panels. Finn Power ran the tool and produced 12 full size sample sheets. They were then shipped to DVB for evaluation. DVB architects liked the resulting embossed panels, which helped seal the deal for the entire project. Eventually, this led to the acquisition of the Finn Power press and a full suite of Mate tooling by Todrin. The tooling package included three additional special Ultra Tec tools for embossing 1 x 2 in, .375 x .375 in and .562 x 1-1/4 in diamond shapes in the required row patterns.

With a full suite of standard tools sizes and shapes, in addition to the four special embossing tools, Todrin was equipped to handle all of DVB's punching requirements plus a lot more. For Todrin's demanding punching operations calling for large volumes of stainless steel often challenging to process, the Ultra Tec tooling is the ideal tool system. Ultra Tec is a fully guided thick turret punching system which increases tool performance and flexibility, offers extended tool life and allows interchangeability with existing systems.

Todrin's newly acquired Finn Power C5 Compact Express is also state-of-the-art. With load-unload automation, its ability to handle, position and stack sheets before and after punching facilitates the high volume requirements ? 2000 embossed panels ? for this, Todrin's initial fabricating project. The C5 is a 20 turret machine, expandable to 100 tool stations using Mate-manufactured Multi Tool holders and MT? tooling system punches, strippers and Slug Free® dies. It is capable of punching maximum hole diameters of 3.5 in with accuracy of ±.005 in at press speeds up to 1,000 spm.

"Consistency of embossing, not speed, is really the key to success with this project," states Nichols. "We're operating at below top press speeds to ensure these results because sheets in the press have to line up just right and the tools have to deliver just the right amount of embossing force. Also, the PVC protective coating must stay intact on the sheet, not only to protect the sheet during and after embossing, but also if it tears or comes loose, the coating material will gum up the tooling and the machine."

Fortunately, they haven't had that problem. "We're operating the press and tooling at the optimum speed to achieve these top quality results, just as was developed in the tooling test at Finn Power," says Nichols. "That test was so important to the success of this project. The entire project has gone forward very smoothly with nary any scrap or downtime."

Todrin Laser Industries, Inc., 600 Somerset Avenue, Taunton, MA 02780, 508-880-2525, Fax: 1-508-880-2626, www.todrin.net.

Della Valle Bernheimer, 20 Jay Street, Suite 1003, Brooklyn, New York 11201, 718-222-8155, Fax: 1-718-222-8157, www.d-bd.com.

Finn-Power International, Inc., 710 Remington Road, Schaumburg, IL 60173, 847-885-3200, Fax: 1-847-885-9692, www.finnpower.com.

Mate Precision Tooling, 1295 Lund Boulevard, Anoka, Minnesota 55303, 800-328-4492, Fax: 800-541-0285, www.mate.com.