SFI Inc. tests Mate Precision Tooling’s punches, forming parts and a partnership

November/December 2011 - Durability, decreased downtime and fast switchover are advantages any sheet metal job shop would want from an upgrade to its turret punch press tooling. After those efficiency factors are accounted for, improvements in the machine’s punching accuracy and a surge in punch press longevity are more than bonus gains. They become the benchmark for the shop’s productivity, success and relationship with its supplier.

Bud Sano, president at SFI Inc., realized such benefits for punch press processes in his Orlando, Fla.-based sheet metal shop. He has built a relationship with Mate Precision Tooling, an Anoka, Minn.-based manufacturer of original and replacement tooling for an array of punch presses that streamlines integration of new punch tooling into his Murata Machinery USA Inc. machines. Mate supplies original tooling for Murata’s punch presses.

“That’s who we started getting our tooling from and started building a knowledge base with them, listening to their recommendations as what to do for the particular machine tool we had at the time,” Sano says of Mate. SFI’s first punch press was a Murata Wiedemann W2040, which originally came equipped with Mate’s Marathon tooling.

In 2001, when SFI replaced its W2040 with a Murata Machinery Motorum 2048 LT and Motorum 2548, Sano upgraded to Mate’s Marathon Plus tooling system, which allows external length adjustment of punch length for proper die penetration. “That makes it much easier and faster,” says Vidal Rodriguez, sales engineer at Mate. Both machines hold sheets up to 4 ft. by 8 ft.

Robust results
SFI’s clientele includes satellite, telecommunications, medical and food service industries. The spectrum of customers requires SFI to process several metals, says Sano. “We do different classes of aluminum, H-32 T6 aluminums. We also do cold-rolled steels, stainless steels, brass and copper.”

Behind the doors of its 28,000-sq.-ft. shop, SFI’s end-use products include electronic equipment such as modems, computer mainframe racks, panels, rack unit panels, telephone switchboards, metal brackets for appliances and chassis for different electronic applications. The Marathon Plus tooling punches are machined from M2 high-speed steel and designed for clean hole edge quality and wear resistance under the stresses of high hit rates.

The punch holders are precision-machined to maintain accurate hole diameters, an important factor when punching at rapid-fire hit rates. “We’ll do little brass shims, stainless steel shims as low as 0.007 in. on that machine, and we’ll get a special tool built by Mate that maybe only has 0.001 in. or 0.002 in. die clearance. So routinely we’ll hold 0.001 in. on a hole diameter on sheet metal,” Sano says, noting typical tolerances are 0.005 in. to 0.002 in. on a fabricated part. “We can stamp out parts virtually to perfection with no burr. We typically get well over 1 million hits on Marathon tooling before sharpening or replacement.”

Early in his relationship with SFI, Rodriguez says the company was having problems with sheet marking and keeping sheet flat because of the outdated urethane stripper, an original tooling style for the Murata punch presses. “We introduced [Sano] to the steel strippers of the Marathon Plus, which helps him keep his material flat,” Rodriguez says. The steel strippers, with their wider holding surface area, eliminate the urethane stripper’s cornering issues and ensure optimal, stable punching and smooth blank removal.

Marathon Plus features Mate’s slug-free dies, which keep the slug from returning with the punch during the stripping step after punching through the sheet.

The punches can hold tight tolerances while under the demands of high hit rates for different materials because of Mate’s precision machining. Bruce Thielges, product engineer at Mate, says the steel from which the tooling is machined must be ground for high precision and have extra-smooth surfaces.

“The steel required for punching is difficult to machine and requires high hardness to hold up in the punching environment,” Thielges says.

With regular use and depending on the specific tool, Sano replaces dies every three or four months. “You can get quite a lot of hits out of [the tooling] before it has to get put down,” he says. According to Murata’s specifications, the 2048 can reach hit rates up to 285 hpm.

“Many customers now demand fast delivery of all their tooling needs,” Thielges says. “This requires Mate to have many pre-hardened blanks available where we finish to the specific point, size and shape once the customer places the order.”

Workflow value
Among the biggest advantages of the Marathon Plus is extended machine longevity, Sano says. “It also let us increase our punch hit rate, and it definitely helps as far as with the flatness of the parts.”

Additionally, the Marathon Plus holder setup minimizes SFI’s downtime. A tooling change takes between two and three minutes. “When we’ve had people here who watch us change tools, we’ve been told that we do it pretty quick,” Sano says.

Depending on the part, SFI will send components for additional finishing such as forming, deburring and welding. Combined with Murata’s punch press abilities, the Marathon Plus tooling can accommodate some of those processes, reducing steps for certain parts. One of SFI’s parts is a custom dishwasher bracket made to attach a dishwasher to a granite countertop. “It’s a stamped-out sheet metal bracket. It has patent pending on it, and it actually has five bends in it,” Sano says. The Motorum 2548 with the Marathon Plus tooling can form the bracket, eliminating the need for a press brake.

“The whole job comes out of the machine, so here’s an application where we run this job lights out,” Sano says. “We take the brackets out of the sheet, put them through a tumbler and from the tumbler, they get pem nuts pressed into them and they ship.”

The Marathon Plus tooling overall has allowed Sano to punch a wider variety of metals rather than needing different punch sets for each material. SFI uses Mate’s stations that hold punching rounds anywhere from 1 in. to 3 in.

Testing tools
When Mate introduces a product, it selects customers that would be ideal to test the limits of the tool’s function and durability. Companies like SFI that process an array of materials at different thicknesses and finishes provide the best feedback. “I like to pick job shops like SFI. [Sano] does copper, aluminum—whatever he can get his hands on,” Rodriguez says. “And it’s such a wide variety of product lines that he gets, so we like to put any tools we’re coming out with in shops like SFI.”

Mate checks for tolerances, premature wear, ease of use, downtime reduction, quality of holes and the nibbling edge blending from hit to hit, Mate’s Thielges says. Once a customer has results, Mate uses the information to “determine if design refinements or improvements are needed or desired,” he says.

It was after one of those experiments with SFI that Sano didn’t want to give back the holders because of the excellent results. That toolset was the Marathon Plus. “We didn’t want to give them back, but I guess we had to,” Sano says. “But we ended up buying them anyway. It works really well.”

Rodriguez adds that because Sano had used a previous-generation Marathon tooling system, he could retrofit the holders in SFI’s Murata punch presses. “What’s good about the Marathon is that for those machines, people don’t have to buy all-new holders because we have retro kits for them,” he says. “But he liked it so much he said he’d just buy new holders anyway.”

With the opportunity to test new products and provide useful feedback, Mate and SFI’s partnership sustains the former’s quality control while giving the latter a glimpse into developing products. “They’re a very good company, and they bend over backward for us,” Sano says. “They do as much as they can do for us, and we’ve got a great relationship.” FFJ

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