Unattended machine operation, 24/7, is very important to high volume companies like BMP Metals Inc. With seven turret presses, three of which operate continuously unattended whenever possible, finding a way to eliminate slow, tedious hand scoring of protective PVC plastic covering on sheet metal parts was key to keeping its automated fabricating processes operating uninterrupted and at top speed. Implementing the Mate Sheetmarker tool system into its Finn Power LPE punch laser system enabled BMP Metals to eliminate the manual operation.

A fully integrated custom precision sheet metal fabricator with additional specialized services in CNC machining and turning, BMP Metals Inc supplies complete product assemblies to the telecommunication, transportation, medical, military, and consumer industries. Its products include everything from seismic rated cable management systems for aerospace applications to high-end barbecues for the consumer market.

The hand operation required stopping the Finn Power LPE laser punch system so an operator could score the PVC covering in order to create holes and openings through which silk screen printing onto the bare metal surface could be performed, while adjacent areas retained the protective covering.

"We manufacture high-end barbecues with 20 gauge stainless steel fabricated panels," reports Robert-Daniel Bedard, BMP's facilities manager. "These parts are punched and laser cut from 48 x 96 in. sheets prior to silk screen printing. To protect these panels during punching and laser cutting operations, we keep the protective PVC covering on the stainless steel sheets. Since the laser doesn't penetrate the PVC material well, the machine operator has to cut a slightly oversized hole in the PVC material, using a special knife with a soft copper blade, and then remove it from the panel. The part moves on for silk screen printing of the exposed metal surface adjacent to the PVC-protected metal. While this process worked, it was slow and didn't take advantage of the high volume automated capabilities of the Finn Power LPE Laser Punch system. We had to find a better way."

Protecting the stainless steel surfaces is critical because any unwanted score marks to the surface makes the part unacceptable and therefore, expensive scrap. Cutting through the PVC covering with the laser was not an option, because depending on the type and thickness of the material, contact with the laser beam causes it to bubble up and separate unevenly from the sheet metal. The bubbles get in the way of subsequent fabricating operations and the laser causes the PVC to melt and stick to the metal components. In addition, the process created undesirable fumes.

Mate Sheetmarker Tool Automates Operation

As a long-time user of Mate tooling for its seven CNC presses, Bedard checked with Mate's sales engineer, Peter Visser, to see if he had any ideas for speeding up the scoring process employing the punching function of the laser/punch system. Visser suggested trying Mate's Sheetmarker tool, together with replacement inserts.

Originally designed to permanently mark sheet metal parts with assembly codes, serial numbers, names, and etchings, the Sheetmarker tool easily converts to cut protective film on metal sheets without marking the metal surface. It does this by creating a toolpath generated by the punch press programming system. The press holds the ram down while the sheet is moved in the x and y axis, creating the desired toolpath and scoring pattern. A brass insert in the Sheetmarker tool is machined to a point that is sharp enough to cut the plastic film but will not damage the sheet metal beneath it.

The versatile Sheetmarker can score PVC material anywhere on the sheet without marking the backside or deforming the material. Scoring is smooth and consistent. The scoring depth is variable, which allows for precise control around complex or intricate shapes. And the Sheetmarker tool is not limited by a particular plastic PVC material type or thickness. Also, the tool is designed with a backing spring so variations in sheet and PVC material flatness or warpage are automatically adjusted for by the tool to retain even and consistent scoring.

For both scoring and marking operations, the tool assembly consists of an insert holder, insert retainer, three springs, and a Sheetmarker roller die. For PVC scoring operations, a softer brass tip is inserted into the tool assembly instead of the usual hard diamond tip used for marking operations. Setup for either operation is fast and easy because no additional machine hardware, such as letter or embossing inserts, is required. Only the simple tip change is needed.

1,000 Sheets Processed Per Day

"We're running lights-out 24/7 using the Mate Sheetmarker to score the PVC on our stainless steel sheets and outputting a thousand a day and 7,000 per week," reports Bedard. "The scoring operation has repeatable accuracy, where before, variations occurred from sheet to sheet and operator to operator. Adding that Sheetmarker tool allowed us to automate a really critical operation and insure part quality to the entire barbecue panel processing operation. It's a great way to add value to parts and protect fine surface finishes while streamlining fabricating operations. We're also planning to use the Sheetmarker, with interchangeable diamond tipped inserts, to produce serial numbers on telecommunication components and other parts."