Copyright Gardner Publications, Incorporated Jun 1992

Still, Harris thinks that the laser will become a standard for a variety of processes, welding and surface hardening notable among them. Consequently, a heck of a lot more companies than Pratt & Whitney will derive benefit from United Technologies' investment.

But right now, Harris says he's surprised at the rate of laser product absorption into industry at large. He is surprised at how slow it is.

UTIL specializies in big lasers. In high-power CO2 lasers. And presently it is working on a very large laser, the Model SM61--a 45-kW laser. It's running this unit under a variety of test conditions in its South Windsor, Connecticut, facility.

Essentially, Jack Davis, UTIL general manager, explains, the new laser is based on many design principles proven in models half its size, principles related to things such as the optical cavity.

Of course, there is a heck of a lot more to it than simply stacking up laser modules to attain more power. Mirrors, for example.

Davis points out that some internal mirrors are having on the order of 100 kW of power active upon them, which can cause very big problems should there be too much absorbtion. Think of the heat. Think of the distortion. Think of the need for new mirrors.

GEAT Industrielaser GmbH of Nurnburg, Germany, is a joint venture. Diehl GmbH, a large German equipment and machinery builder, owns 49 percent; United Technologies owns 49 Percent; a German bank consortium owns two percent. The unalloyed purpose of GEAT is to get UTIL lasers in the hands of people.

According to Helmut Burkhardt, managing director of GEAT, those hands more than likely build cars. He explains that the European auto industry is doing a great deal to push laser technology forward. That is, he says, even though the initial investment for a laser may be higher than a conventional alternative, if economic calculations show that there may be an advantage to using the laser, they will take the risk and use it. "And it is a risk," he states. (Chances are, he explains, the laser system will be an integral part of the production process, and should it go down...they're not building cars.)

The Germans aren't slouches when it comes to producing CO2 and YAG lasers. About 30 percent of the world market total hails from there; most of them--and most of those applied in Germany--are less than three kW. Their predominate application: cutting. Results are most evidently visible in that task. Burkhardt believes there will be a change: welding and surface hardening. Which means higher power lasers. Which means, perhaps not uncoincidentally, UTIL-style lasers.

Audi AG is a pioneer in laser processing. And it continues to use lasers, 10 years on. Dr. Rudolf Wanke describes one installation, a 14-kW UTIL CO2 laser, which is, apparently, the first laser greater than 10 kW in use by any European automaker in a production application. The system is configured into a gantry workstation. And Wanke points out that in the context of the manufacturing equipment in the plant, the laser system is difficult to discern, as it is just another piece of equipment, not something treated in a special manner. "This, I think, is the right way to do it," he opines. The low-carbon steel parts go straight from the stamping operation, uncleaned, oil on the surface, to the weld station.

The part is a rear suspension component for the Audi AD Quattro, a deep drawn component. The length of the weld is 4.2 meters: the width is on the order of 0.5 millimeters. Presently, welding is performed at 2.8 meters per minute, which is sufficient to meet the present low volumes. But in order to ramp up up to 2,000 components per day, Audi engineers will have to get the system running at 5 to 6 meters per minute, which, apparently, is possible.

Wake says the low-carbon steel component is being laser welded rather than being processed with metal active gas (MAG) welding because there was a concern about the distortion that could result from the heat input from MAG, which would neccesitate another processing step. It's not that the laser isn't creating heat as it operates at 12 kW, but its speed prevents distortion and cracking.

One of the necessary things for the production of tailored welded blanks--realize this is butt welding, edge-to-edge--is that the gap between the two sheets brought together ought to be on the order of zero. Dr. Charles Mombo-Caristan, of Thyssen Steel, mentions that a 0.003 mm gap will do.

So how do you get there? Thyssen is working on a couple of approaches. One visible. The other audible. The visual syytem, in use in the production of automotive floor pans, utilizes a halogen light source and a CCD-camera to follow the seam. The other puts a microphone in the welding chamber. Operators know what a good weld sounds like. And so they know what the frequencies are when there are problems. At this point, he says, if there is an audible indication of a problem, it is necessary to visually inspect the weld to check out the problem.

Jean Bernoilles, a consultant to Creusot-Loire Industries--a French manufacturer of armored military vehicles--maintains that although it is, indeed, important for there to be a good fit up, or narrow gap, between sheets to be joined with the laser butt welding process, he stresses that there are a couple of other aspects of the material that ought to be considered. One is flatness. The other is chemistry.

That is, Creusot-Loire produces its own plate--high-carbon steel--to produce components for its vehicles. People think, he says, that high-carbon means that welding is difficult. But Creusot-Loire, he notes, has micro particles of carbon, microcarbides, which not only facilitate welding but which, apparently, are helpful to those people inside the armored vehicles as it helps with ballstic resistance.

The lasers are operated at Mechanique Creusot-Loire, at the Atlas Laser workshop in the city of Saint-Chamond. The workshop, Laurent Gouthier, engineer in the production department, says, was established in 1985. Both laser cutting and laser welding of armored steel that may be from three mm to 14 mm thick are performed on laser machines that range in power from two kW to 14 kW.

Gauthier cites several production advantages of laser welding. One is that the amount of fixturing needed to conventionally weld a vehicle is much greater than it is when laser welding is used, and because they are tailoring blanks, the number of reinforcements ordinarily necessary is also greatly minimized. Also, because tooling and fixturing requirements are reduced, JIT operations are facilitated in what were previously long-lead time components. And lower heat distortion means higher product quality.

Burma, Bangaledesh, Sri Lanka, Vietnam. China, India, Thailand, Philippines, Malaysia. Hong Kong, Singapore, Taiwan, Korea, Australia, Japan. Welcome to the Pacific Rim. And as you work through the three groups, as you move from Burma to Japan, the flow goes from low to high technical and economic sophistication. So says John Wood, who works as an agent for UTIL in that part of the world. And it sounds like an ideal place for such a person to be.

Wood: "There are unparralleled market opportunities for high-tech companies: These countries are looking for ways to build their infrastructure and ways to produce high-tech products."

Australia, he points out, has recently changed tax laws to provide higher depreciation rates for investments in capital equipment. And GM, Ford, Toyota, and Mitsubishi all have significant facilities there.

The government in Singapore is interested in developing the wherewithal to produce lasers for export.

Malaysia is in year two of a five-year industrial improvement plan. Wood makes a couple of interesting points and one that's impressive. One is that the country--which has involvement in automotive, aerospace and shipbuilding--is far more powerful than its size might indicate. The other: "It wants to invest in the most advanced technology, not in something that will be obsolete within two years." And as for the somewhat scary one: a 2,250 kilometer gas pipe line is proposed. It could be laser welded.

Taiwan: Tens of billions of dollars are to be spent. "It wants to be a big player in aerospace."

Wood talks about Pacific Rim investments in airports, highways, elevated rail systems, power generation systems...all projects with big consequences for manufacturers lucky enough to hook up with some of them.

Masakazu Tsuji hails from Japan. Osaka. He's with a company called Hamsa. Sells UTIL lasers. Says there are about 5,000 CO2 lasers in Japan. About 75 percent are in the low-power category. ("Low" is a relative term. Figure less than 2.5 kW.)

Apparently, Osaka University has the biggest laser right now: 15 kW. But don't breathe too easy. A steel producer is going to take delivery of a 22-kW unit and several other deals are in the works for units greater than 16 kW.

Conrad M. Banas, chief scientist at UTIL, admits that as recently as two years ago, he didn't give much thought or credence to high-power laser machining. He recalls a U.S. Air Force program of 10 years ago, a two-year "laser-assisted machining" project. A laser was used to heat hard-to-machine materials to a semi-plastic state just ahead of a cutting tool. As an idea, it was probably pretty good. As a practice, it wasn't successful. And it put a damper on additional developments.

Banas had his interest piqued in response to a situation that Pratt & Whitney has. The part in question is a forging, a nickel-based alloy, Inconel 718. It starts out weighing 75 kilograms. Rough machining takes it down to 25 kilograms (on the way to a final 15 kilograms). Here's the incentive: the rough machining requires nine hours. And Banas figures the rate is $100.00 per hour in the machine shop.

Apparently, a professor at MIT came up with another laser machining concept. This involves using two lasers, intersecting to form a right angle. So they tried it. And, with the 14kW lasers, were able to do in seven minutes what once required nine hours. However, as these things happen there was a snag. Some of the features on the component are just 1.5 mm, and the cut--a rough one--might result in burning some of those features off. So now they are working on an alternative melting procedure with the two lasers. Now they do the nine-hour job in 51 minutes.

Near as we can tell, states in the United States seem to be involved in social programs of one sort or another, whether it's providing funds for training or providing funds for those in need of funds.

Which means that we are taken aback of the presentation of Dr. Heinz Witulski, who is a public servant, from the German state of North Rhine Westfalia. As German states go, it's not a big one. It is an area where there is a concentration of steel producers.

Get this: In 1984 the state launched a laser program. It established organizations to get lasers out in industries. It formed groups combining government, academia and industry. It set up a laser job shop. It purchased the third 22kW laser UTIL built.

The state is behind a variety of programs. Like using laser hardening to extend the life of tools for warm and cold forming. (How many officials in the U.S. even know that such processes--any of them--exist?) The state is promoting work on using lasers to weld light-weight structural members, such as I-beams that consist of welded square tubing, and honeycomb sheets for panels. The state is underwriting the creation of a high-investment laser job shop. And we can only think that this is just one area of technical concern of just one state in Germany.

The U.S. Navy has interest in lasers for a variety of things. So says Paul Denney of the Applied Research Laboratory, Laser Material Processing Group, Pennsylvania State University. The Navy funds it. There's a material the Penn State group developed, LASCOR, a laser-welded panel material: high-strength, light-weight. It could be used as aircraft carrier doors and permit the addition of three aircraft on the carrier. Or it can be used in the construction of off-shore oil platforms. And it exists only because laser material processing makes it possible.

The Navy is interested in laser cladding valves with Stellite. And nickel. And cladding aluminum bronze propeller blades with nickel-aluminum bronze. Once again, laser processing.

The Navy has some 50 decommisioned submarines. It wants to get rid of them. So the Penn State researchers are proposing laser cutting: slicing the subs.

And there are things that break on active ships. So the Navy is interested in getting a low-power portable YAG laser that it can place on a dock, then run fiber-optic lines to the repair site. The good news about these and other projects is that Denney says they can save the Navy millions of dollars. Which means we save them.

Alan J. Ittleson of Pratt & Whitney Aircraft walks through a project. Hardening the outer blades of gas turbine engines. This is something P&W--and presumably other jet engine manufacturers--does quite a lot: on the order of 5,000 per year.

Initially it was a manual task: gas tungsten arc welding. Strike an arc and feed the wire. Cobalt alloy on a nickel base. The tooling was simple. But there were some problems. The job was operator-dependent.

Consistency varied. So there was rework. The processing time was on the order of five minutes per part. The welding wire was a bit pricey: $87.00 per pound.

Then, in 1982, a six-kW CO2 laser was installed to do the task. In this case, a preformed insert of hard facing material was placed on the part, then melted with the laser. This procedure allowed better control of the process parameters (e.g., heat, speed). Cycle time was reduced to three minutes and material cost was down to $75.00 per pound. But the tooling was more complex compared with the manual, and the operator sometimes had difficulty selecting the right nugget to match the particular blade, of which there are more than 50 versions.

Meanwhile, the configuration of the part changed such that the parts were cast closer to final size and so the amount of post-hardening machining was reduced. The tooling for laser processing the blades become more complex and operators had to use tweezers to put the nuggets in place. Certainly not a particularly productive approach.

So a different method was developed. Nuggets have given way to powder. The powder is applied through an argon gas jet. Layer upon layer is built up. The operator need only load and unload. Processing time is on the order of two to two-and-half minutes; the powder cost is $20.00 per pound. Different blades are handled through a program change. Should problems occur, they are consistent ones.