New Market Opportunities for the Laser

Have you priced a trimming-die operation lately? Many OEMs have, saw how expensive they were and looked for alternatives-including the laser.

Many would argue that, in some markets, the number of shops that offer laser cutting has reached a point of saturation. In some areas, hourly rates have been on the decline as more shops enter the laser-cutting game, says Thomas Burdel, vice president of sales and marketing for Prima North America (Chicopee, MA), up to 90 percent of the laser-cutting market involves 2D systems.

For some laser services, the price-per-hour hasn’t seen such decline: 3D laser cutting. Fewer shops offer the service, and recent years have seen significant upticks in demand for such services. Says Burdel, much of today’s 3D laser cutting involves the trimming of stamped components, serving as a cost-effective replacement for trimming-die operations. Another application: say a part with a hole needs to be bent, but the bending process distorts the hole. With 3D laser cutting, Burdel explains, the sheet can be bent, then cut afterward, with no worries of distortion. Another area includes flat-cutting of thick sheet requiring bevel cutting, possible due to the laser head’s five axes of motion.

Today new applications for the 3D laser include those for the high-end appliance industry, utilizing stainless steel. “Stainless can be very hard on trimming dies,” Burdel says, “so for these applications the laser solution is ideal.”

Other applications involve hot-stamped parts in automotive. With the help of heat, automotive companies can now stamp thinner material-say, 0.060 inch, down from 0.080 inch-and improve structural integrity at the same time. But the process also makes the product extremely hard, roughly 60 Rockwell, so “in these cases, trimming dies just don’t work anymore,” he says. In this situation, and in many others, the 3D laser has stepped up to the plate.

CHALLENGES

These applications, and many others, require the laser head to follow the stamped part’s contour precisely, being careful not to alter the focal length between the head and sheet-metal surface, always staying perfectly perpendicular to the cut, and ensuring collisions are avoided.

Prove-outs of the process ensure no collision occurs, being sure to account for springback and other effects of formed material. Unlike when dealing with flat sheet, trimming certain formed part with a laser can release pressure on the material, slightly changing the material dimensions.

Users must also consider scrap evacuation. A large piece of scrap falling after a long cut can inflict some serious damage if it hits the workpiece.

FIXTURING AND PROGRAMMING

That said, major considerations for 3D laser cutting-over typical 2D work-involve two factors: fixturing and programing.

Burdel organizes fixturing under two categories. First, there are high-production fixtures, often used in automotive, with automatic clamping and unclamping, automated and incorporated into the laser control program. “A fixture like that may cost more than $30,000 or $40,000,” Burdel says.

The second involves what is called “egg crate” fixtures, which are assembled through welding or slots and tabs. These fixtures usually don’t come with clamping, but merely provide a “steady rest” for the material. Clamping may be added, of course. But often, since the laser, being a “soft” tool, doesn’t touch a part, so a setup may not require hard clamping. This fixturing often finds a place in a job shop with relatively low volumes.

The second key differentiator from the 2D world involves the programming. “Today’s software has become very powerful,” Burdel says, adding that, perhaps more than anything else, software advances have helped proliferate 3D laser cutting technology. The teach-in methodology can still be used, but taking the prep work offline, away from the shop floor, has boosted the technology’s productivity in recent years.

In automotive circles, for instance, many systems allow a seamless transition from CAD programs like Catia down to CAM and offline process setup and simulation for 3D laser cutting.

For applications involving the “egg crate” and similar fixturing, the offline software creates a 3D program simulation, and designs the fixture for it, and accounts for the cutting head dimensions. For obvious reasons, if the control does not know the size of the cutting head being used, the potential for collisions rises drastically.

3D laser systems move in five axes in motion: X and Y (like in 2D systems), Z (the movement of the laser head perpendicular to the workpiece); and A and B, where the head moves laterally, principally for bevel cutting. Yet another direction of motion comes from the head itself, which moves to adjust the focal length, depending on the material. And for applications like tube cutting, the part itself can be rotated about its axis. All movement comes through direct-drive, gearless technology that eliminates backlash.

THE BUSINESS CASE

In some markets, hourly rates for 3D cutting can be more than double that of 2D cutting, Burdel says. True, the process does involve additional costs. The initial equipment investment is more-but that investment can involve a machine that can do both 3D and 2D work, giving tremendous flexibility for the shop floor. And programming, fixturing and material challenges also add to the mix, and all this requires shop-personnel training and expertise.

But a shop can charge more per hour for all that work, of course. “At the end of the day,” he says, “you’re still making more.”

Editor’s Note: For more information contact Thomas Burdel, at (413) 598-5256, tburdel@prima-na.com. Artwork courtesy of Prima North America, www.prima-na.com.