Jeff Moss, president, DCT, Inc., and Randy Keller, vice president and general manager, Utilase Systems, a division of DCT, are standing on a mezzanine that's been constructed in one of the linked buildings that houses Utilase in Detroit. The mezzanine will eventually be shipped, along with three others, to the facility of a tier-one supplier. Below the deck is an assortment of yellow Fanuc robots. Some of them are to be used for material handling. The processing equipment—at least part of it—is up on the deck with Moss and Keller. There are several 1-kW Haas HL703D Nd:YAG laser resonators from the Laser Div. of Trumpf Inc. up there. When everything is in place, there will be 34 lasers and 34 robots. The application will be used to cut hydroformed tube. The tube is for cross-members and rails of a forthcoming full-sized pickup. The rails are 14 ft. long. Some of the holes are 6 to 8 ft apart.
Moss asks, "If this piece was being made with conventional hole-making equipment, punches and dies, how would you get the mandrel in that far and make production? If the cross sections of the holes were small enough, they could be put in with drills, but that's not the case here." Keller adds, "We're cutting odd-shaped features for attachments—not just round or square shapes."
Utilase was established in 1986. The company has installed plenty of automotive laser systems for the auto industry, and it was on the leading edge of laser tailored blank manufacturing, a part of the Utilase business that was recently sold by DCT*. As Moss puts it, "We've' seen every kind of laser that you can imagine." The company has served as the beta site for several lasers. Next up is the 6-kW diode-pumped Nd:YAG being developed by the Precision Laser Machining Consortium (of which Utilase is a part); the consortium is working with funding from the federal government's Advanced Projects Research Agency (ARPA). Utilase is also presently working with another company on a NIST grant to develop a 1-kW direct diode laser. These guys have been around.
As the two stand on the mezzanine in other parts of the facility, work is being done on transmission welding systems for two of the Big Three, one employing 11 14-kW CO2 lasers from Convergent Energy, the other with 7 6-kW CO2 lasers from Rofin-Sinar. (Certainly one of the biggest application areas within the auto industry for lasers is in transmission welding. Moss explains, "In transmissions, the components are critical and tightly toleranced. Low heat input is a re-quirement. Welding is typically done with electron-beam or laser systems. Lasers have proven to be more reliable.")
Hydroforming & Lasers
On the subject of the frame rails, Moss explains that the standard operating procedure is to start with two pieces that are formed and pierced, then MIG welded together. Not only is this time consuming and equipment intensive, but there are some limitations when it comes to making design modifications. That is, if a design engineer decides that it is necessary to move a pierce punch or a drilling station, a few days may be required to make the change. With the robot setup, it is a matter of a few minutes.
Hydroforming means that a single piece is being processed. Which, in this inventory-conscious era means that hydroformed components should be growing in use. Moss and Keller admit that plasma cutting can provide similar results, but that the operating costs for the plasma systems are higher. For one thing, the starting and stopping of the arc that occurs eats up electrodes. What's more, there are possible maintenance headaches in that if there are 34 electrodes, the wear rates are likely to be inconsistent, which would keep maintenance personnel jumping, to say the least.
The diode-pumped YAG laser being developed by the ARPA consortium (one is supposed to be a 2.5-kW unit; the other, the one Utilase will be getting, is planned to produce 6 kW) are getting closer to moving out of the lab and into production. In April, for example, TRW, the company that's heading up the Precision Laser Machining (PLM) consortium, announced that tests on cutting 1/8-in. thick graphite epoxy composite sheets were highly successful, resulting in cut edge quality far superior to those provided by either CO2 or conventional YAG lasers. Robert Brown, PLM principal investigator, United Technologies Research Center, observed, "We've been looking for a way to cleanly cut high performance, high precision graphite epoxy parts for some time." They may have found it.
There are several benefits of diode pumping, such as higher peak and average power, lower maintenance (diodes last longer than lamps), and smaller packaging (4ft3). A real key is the quality of the beam. This means there can be long stand-off distances and yet a tight focus. According to Moss, a real benefit may be achieved in welding operations. "This should allow laser processing at speeds competitive with resistance welding," he says.
Laser in a Coffee Can?
The NIST-supported direct-diode laser that may be ready for beta testing at Utilase next year may be even more interesting. Keller says that in this case, the diode is it. There is no other media, as in the case of the diode-pumped YAG. "We should have a 1-kW laser in the size of a coffee can," he says. YAG lasers have made big changes in industrial ap-plications because of the ability to pipe their output through fiber optics. In the case of the direct-diode laser, things can be still simpler: Attach it to the end of the arm of a robot and just provide power. Because a diode has a single wave length, the beam quality is extremely high. The high power in a small container may have some nontrivial effects on the way cutting and welding are done in production operations. Of course, the jury isn't still out on this one because it is still way to early to tell how it will turn out.
One thing is for certain, though: industrial lasers may have finally achieved the status of being workaday tools, but the development curve—in terms of both the technology and the applications—is far from bottoming out.
*Note: The Utilase Blank Welding Technologies division of DCT was sold to Noble International Ltd. (Bloomfield Hills, MI). The company will continue to be called Utilase Blank Welding Technologies, but it is a separate company from Utilase Systems and DCT. Utilase Blank Welding Technologies recently opened a plant in Brantford, Ontario; it will be equipped with four lines for blank welding. Additionally, it is planning to increase the number of weld lines in its Detroit facility from eight to 12. It is estimated that when it has 16 lines up and running, it will have the capacity to weld some 10 million car body blanks per year. AD&P