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On a beam of opportunity: lasers redefine shops' approach to manufacturing.

The laser's role on the shopfloor continues to evolve - so much so, in fact, that the laser is pushing the shop to evolve as well.

That's certainly the case at Laser Precision, a three-year-old laser job shop in Mundelein, IL. There, 14 employees use three lasers to precision-cut parts in increasingly large lots for a variety of customers. "We are primarily a laser job shop, but over the last year we began to see opportunities to better serve our customers by offering additional services," says Diether Remeikis, sales manager. "We began to get more calls to branch out our services into the forming and fabricating arenas."

In doing so, Laser Precision has built its expansion around its three Mitsubishi lasers, including the Model 2512 LXP with its speed-demon workpiece shuttle table. The company routinely cuts parts to [+ or -]0.002[inch] or better from a variety of materials. It processes miniature parts from 0.001[inch] stainless steel shim stock up to highly specialized machinery parts measuring 1/2[inch]x46[inches]x95[inches]. The range of processing includes materials up to 1/2[inch] carbon and stainless steel, up to 1/8[inch] aluminum, copper, brass, and bronze. A typical production run averages 250 pieces.

The lasers also represent a critical component in Laser Precision's concurrent engineering strategy. When a customer has a part design in process, its configuration and geometry are fed into the company computers, in which layout and cutting sequences can be programmed simultaneously. That translates on the shopfloor into faster start-ups and less scrap.

Company president Jeff Adams points out that the versatility of his lasers' resonators is an especially competitive edge. "The rectangular waveform pulse permits us to generate very high peak with our beam without developing excess heat build-up in the part," he explains. "Thus complex geometries and shapes can be processed."

Custom-tailored

For many companies like Laser Precision, laser technology ensures efficiency, accuracy, and repeatability. At the same time, laser manufacturers tailor laser systems for customers.

Terry VanderWert, product manger at Lumonics' Eden Prairie, MN-operation, says people are looking for user-friendly laser systems. "One of the areas were working in is making the laser process faster," says Mr VanderWert. To design a fast laser, Lumonics first determines the laser platform best suited to the customer's needs. Lumonics' FineCut laser system is a 2D metalcutting system geared toward flexible manufacturing and cutting intricate parts. A laser type is then selected according to the customer's requirements (i.e. 500 W to 4 1/2 kW). Finally, peripheral equipment and other parts are added - software, motion control systems, and sensors. The FineCut laser's work envelope is 24[inches]x28[inches]x3[inches], XYZ axes.

Tom Getts of Lumonics' Livonia, MI-operations says customers want systems that are available on demand, simple to operate, able to withstand the harshest environments, and require as little maintenance as possible. Laser users like touch-screen control panels, graphic displays, and module exchanges. Customers also like the service of a mobile link to Lumonics' Livonia, MI Support Center. The link lets the support center "read" a customer's laser operational conditions via computer linkup to pinpoint possible problems.

Mr VanderWert points out that lasers must operate with simple tooling and at ever-increasing speeds. Lumonics' hardware/software component Feature Finding locates tooling and part-reference features, reduces setup time, and compensates for part variations. For example, if a workpiece in a fixture varies in shape from the previous shape, Feature Finding knows where the hole location is to be made.

Some manufacturers want total-solution laser systems. The LaserDyne 890 from Lumonics is an example of how a system has evolved into "one-stop shopping." Lumonics increased the Y-axis travel to approximately 13 ft, enabling it to process 8[feet]x10[feet] and 8[feet]x13[feet] plates, as well as tubular parts and large, formed 3D shapes.

In addition, TeachVision, available with the LaserDyne 890 BeamDirector, allows the user to manually "teach" a scribed pattern on a part by using a closed-circuit color camera to trace out the pattern. The scribe image is viewed on a liquid crystal display and, embedded in a user-friendly, hand-held pendant. The process involves positioning the BeamDirector nozzle over the part and storing individual points along the scribed part as the nozzle is scanned along the scribed path. The positioning accuracy of the taught points is [+ or -]0.025 mm ([+ or -]0.001[inch]), which is said to be approximately three to five times better than other methods. Teach-Vision also works well for verifying and modifying part programs developed off-line on a CAD/CAM system.

According to Mr Getts, multiaxis laser technology has become a standard manufacturing process with the Big Three automotive manufacturers and its suppliers. Laser systems are used to trim aluminum and steel body panels in all types of cars, vans, and trucks. The systems increase design flexibility, cut processing costs, reduce the weight of the parts, and increase vehicle strength.

Mr Getts also reports many aerospace company in the world uses Lumonics multiaxis laser systems, covering work from turbine engine manufacturers to scribing maskants used in chemical milling of large aircraft skins. For one aerospace company, Exacto knives have been replaced with the LaserDyne 890 for precision cutting. Benefits have been realized in the form of reduced maskant scribing times by 50% to 80%, improved part quality, elimination of more than 50 hard-tooling fixtures, $1.5 million savings in nonrecurring tooling costs, the elimination of fixture storage areas, and the reduction of total setup time from two hours to 10 min.

Alternative processing

Lasers provide flexibility, high material utilization, and a repeatable, controlled process. Thus, when Lawrence Livermore National Laboratory (LLNL), Livermore, CA, was called upon to manufacture 4500 stainless steel cathode assemblies for a state-of-the-art distributed ion pump (DIP), a substructure of a collider, it decided laser processing was the most effective solution.

Minneapolis, MN-based Laser Applications Inc (LAI) had done work in the area of beam splitting, which takes a single laser beam and separates it into two independent cutting sources. The procedure allows two parts to be cut for the same physical motion as one, resulting in twice the output for the same cycle time and reduced costs.

The project involved laser cutting and laser welding of the DIP components through LAI East Inc, Westminster, MD. The 316 L stainless steel was first cut into 6[inches]x30[inches] sections, with the laser cutting to follow. While the laser was in cycle, the operator would either shear, bend, or inspect the material. Two parts ran while two others were loaded, so the machine was constantly in operation. Laser fixtures were designed with a vacuum to hold the material fiat and to safely remove exhausted materials and gases. After laser cutting was complete, the parts had to be sent out for stress relieving, cleaning, and electroplating.

The next step was laser welding, a procedure performed in a clean room conforming to Class 10,000 standards. The welding operation also required a shorter wavelength laser - Nd:YAG. Traditionally, laser welding is fast, and part presentation takes on a more significant role. In most welding applications, welding time is measured in sec. However, if it takes minutes to load the fixture and present it to the laser, machine utilization is wasted. LAI had two fixtures - one used to weld, the other to load during the cycle time.

According to LAI, the use of lasers for the project offered several benefits, including:

* Avoidance of tool contact. Because the delicate nature of the part and that 72% of the material was being removed, mechanical deformation with conventional drilling or punching would have induced too much stress.

* Cost effectiveness. The laser's ability to focus energy to a small diameter (0.005[inch]) reduced material consumption and allowed for nesting.

* Tight tolerances. Some parts' features had tolerances of +0.002[inch]/0.000[inch].

Laser partnership

Where will lasers take shops in the future? Rofin-Sinar Inc, Plymouth, MI, and The Fraunhofer Institute for Material and Beam Technology (IWS), Dresden, Germany, have successfully cooperated in developing and testing methods of materials processing using high power CO2 and Nd:YAG lasers. And techniques have been developed for welding high carbon steel using a combination of laser beam and induction heating - resulting in multiple installations at a major European automotive manufacturer. Another success was in the welding of aluminum car components using filler wire.

The IWS' latest milestone is the production of a hard coating with low friction properties for use on components and tools operating under low lubrication conditions. The coating, applied in a special laser-assisted sputtering technology, enhances the material quality with respect to wear and friction properties.

The IWS also brings access to the latest equipment for metallurgical analysis and lifetime testing of components. This, in combination with beam handling and shaping systems design and full process development, the collaboration between RofinoSinar and the IWS is expected to bring new developments of advanced production processes, including quality control.

The partnership will operate out of Rofin-Sinar's application center in Plymouth, MI. Rofin-Sinar will contribute laboratory resources and facilities, IWS the necessary manpower and applications expertise. The center, already equipped with high power CO2 and Nd:YAG lasers and CNC positioning systems, is expected to also house multiaxis beam handling and robotic systems.
COPYRIGHT 1997 Nelson Publishing
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Copyright 1997 Gale, Cengage Learning. All rights reserved.

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Title Annotation:job shops
Publication:Tooling & Production
Date:Aug 1, 1997
Words:1550
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