Laser Services Incorporated is a Westford, Massachusetts, job shop. Its living comes from making parts for customers. Founded in 1979, it has grown from three employees and 2500 square feet of manufacturing space to more than 50 people working in a purpose-built, 17,000-square-foot facility.

As the company name clearly states, this shop is into lasers. They built their business using laser processing technology to make parts for more than 400 customers. It's their specialty, and it's a specialty that has seen steady growth in application.

Much of their growth has come from metalcutting and fabricating shops that recognize that laser technology may be applicable to a job they have contracted to produce. For most of the shops, however, the volume of laser-potential business is insufficient to justify the capital and labor investment necessary to bring laser capability in-house.

We talked to Laser Services founder and president, Bruce Beauchesne, about when laser processing technology makes sense for shops looking to satisfy the expanding breadth of customer requirements. He has worked with lasers since 1968 and has "been-there-done-that" through the gee-whiz early days of lasers to today's practical production use of the technology encompassing a wide variety of applications.

Need For Networks

It's not news to many businesses that the manufacturing environment has changed in the past few years. Shops of all stripes are being stretched to the limit by customers demanding increasing amounts of service. In many cases, that means asking the shop to move beyond its traditional niche. For some job shops, part of that job now means contracting for services from other job shops.

"Machine shops are among our largest bases of customers," says Mr. Beauchesne. "Pressures are being brought to bear on these shops from downsizing customers who no longer want to make every part that goes into their final product." These customers also want to reduce the number of suppliers they have to deal with. This has created networking opportunities among contract shops.

"In many cases, it's almost a barter economy," says Mr. Beauchesne. "Let's say I have laser services available but need to turn some stock before I can work on it. A turning shop up the street needs to mark parts with sizes or operation directions. We do a deal--he turns my parts and I laser mark his."

So the originating customer deals with a single contractor who in turn networks with other shops whose specialty is needed for the job. Laser processing is one of those manufacturing specialties.

No Solution Looking For A Problem

The laser (light amplification by stimulated emission of radiation) of the past was a cantankerous and expensive maintenance nightmare and a technology best confined to the TLC (tender loving care) available in laboratories or R&D facilities. With the exception of prototypes, they were far from practical in the workaday world of commercial application.

In spite of that, early on (circa 1965), a few companies braved the numerous down sides of lasers and in doing so, proved their processing viability. "Other than some Bell Laboratories engineers, one jet-engine manufacturer and a few laser `jocks,' lasers were touted as a solution looking for a problem," says Mr. Beauchesne.

That's no longer the case. Worldwide, laser technology has been proven as a viable manufacturing tool. Its processing versatility, especially in terms of short setup times and virtually zero hard tooling requirements, places lasers ahead of some processing technologies in responding to JIT (just in time) and ship-to-stock inventory conventions.

"The question for many machine shops is when the laser makes sense over other processing techniques," says Mr. Beauchesne. "That takes an understanding of the technology from an applied perspective." Shops like Laser Services have that perspective because laser is all they do.

Cutting, Welding And Marking

Lasers are ideal tools for thin workpiece materials that are difficult to hold on conventional metalcutting machine tools. They also provide excellent process speed for cutting holes of different sizes. Intricate cuts on undulating surfaces are another strength of the process. These attributes also apply to laser welding and marking.

At Laser Services, and for most metalworking applications, there are two kinds of lasers used. One is YAG (yttrium aluminum garnet), and the other is CO2 (carbon dioxide). In general the CO₂ is the more powerful laser type. Its application is primarily in metalcutting.

A laser cuts metal by eroding away the parent material. It literally explodes tiny chunks of the workpiece as the beam passes through. The result of these miniature explosions is a very rapid metal removal rate.

For welding, the laser beam can be modified to penetrate a workpiece at a prescribed depth. In this case, the energy is concentrated on the work as heat. This technique plasticizes the workpiece allowing welding action to take place. Lasers can join materials with or without the need for welding material. "It is very effective for joining dissimilar materials," says Mr. Beauchesne.

The YAG laser uses a different light generation medium than CO₂ and typically operates at lower power levels. It's used for many welding applications because its finer control capability and lower power output generate less heat in the material around the weld.

Controlled depth of penetration makes possible the third primary laser operation, which is marking. Beside the use of marking instructions, commercial messages (logos) or other information on parts, a growing number of manufacturers also want their parts marked for traceability requirements.

Laser cutting, welding and marking are the three big metalworking categories. There are alternate methods to do many of these applications with processes other than lasers. So why consider a laser shop?

Processing Advantages

Not even the most radical proponent for laser processing technology suggests that lasers can replace most other metalworking techniques. There are things, though, that lasers can do better, faster or cheaper than other production methods.

A laser job shop's overall advantage to a customer is turnaround. This explains the wide application in prototype production. There are also throughput enhancements inherent in laser processing for part production that metalcutting shops and fabrication shops simply must live without.

Laser is a non-contact metalworking technique. There is no cutting tool pressure to contend with, so the tooling and fixturing requirements are significantly reduced. "Simplified workholding requirements allow a laser job shop like ours to set up and run an order without the leadtime necessary for fabricating ruggedized fixtures," says Mr. Beauchesne.

A laser also carries a full complement of "cutting tools" at all times. Variations in material thickness are dialed into the laser. Depth of cut is a control feature so different cutting tools are not needed.

For hole cutting, size is programmable from a few thousandths of an inch in diameter up to any size needed. Holes are cut using a circular interpolation, and at the high speeds a laser can cut, it can process a lot of holes in a very short time.

Laser drilling and cutting tolerances will vary depending on several factors including the type of material, thickness, cutting speed, surface condition and laser cutting parameters. A typical tolerance for hole diameters under 0.125 inch would be ±0.001 inch. Holes 1 inch in diameter or larger are typically held to ±0.005 inch.

Cutting profiles that are under 12 inches in length can be held to ±0.002 inch. Linear cuts over 12 inches and up to eight feet have tolerancing of ±0.005 to 0.015 inch respectively.

It's a 44-inch-diameter dish with 18 holes of 8 1/4 inches in diameter that are held to ±0.020 inch. The work-piece has three additional holes 1 1/4 inches in diameter that are held to ±0.005 inch. It's cut from 1/4-inch stainless steel in typical lot sizes of 20 pieces.

Another application takes laser hole drilling to an extreme. It's a 24-inch-diameter by 30-inch-long cone that requires 11,000 holes over its surface. This application is ideal for laser processing. It's quarter-inch-thick stainless. Cutting all the holes would require a special fixture and a great many drills on a conventional machining center.

The Heat Is On

All laser metalcutting creates a heat-affected zone (HAZ) on either side of the cut. A goal in laser processing is to minimize this HAZ.

Matching the right laser to the material to be processed is an advantage that a laser job shop brings to the situation. "We have 25 different laser units in our shop," says Mr. Beauchesne. "We can put a job with high reflectivity on a YAG, for example, and get a higher quality cut or weld because of the finer controllability of the unit.

"Even though the processing speed might be a little slower than more powerful CO₂ lasers," he adds, "the reduction in HAZ will actually save overall processing time by reducing secondary operations that would otherwise be needed to clean up the workpiece."

In general laser-processing practice, an assist gas is used. The assist gas, usually a mixture of air and an inert gas such as helium, performs several functions. It cools the workpiece, which reduces the HAZ. Assist gas also reduces the reflectivity of shiny material so the laser doesn't bounce off. (Remember, a laser is light, which can be reflected.)

"Manipulating the assist gas is key to getting minimum HAZ in our shop," says Mr. Beauchesne. "In laser processing, you can't eliminate the effects of heat, but there are techniques that will greatly reduce it."

Other Services

After some shops see the processing benefits of lasers, they decide to invest in the technology for themselves. Laser Services has helped several of its customers transition to laser processing. "We may lose a direct customer," says Mr. Beauchesne, "but we gain a friend. In most cases that shop has ongoing system service requirements that we can provide, so it works out."

A shop looking to move into laser technology as an augmentation to other services will find that the technology today is more user-friendly than in the past. "It's my contention that if a shop has a good EDM technician or a good CNC machinist, with a couple of weeks of training, we can get them self-sufficient on a laser," says Mr. Beauchesne.

The point is that laser technology is now sufficiently mainstream that shops do not need a degreed laser person or laser engineer to add laser capability to a business. If, on the other hand, lasers are a specialty that would be nice to acquire on a contract basis, Laser Services and many shops like them throughout the country are available to you.

For more information about laser processing in general or, for analysis of a potential laser application, call Laser Services at (508) 692-6180 or send a fax to (508) 692-7271.

Laser Job Shop Scenarios

According to Mr. Beauchesne, there are five different job shop scenarios that generally involve his company. These assume that there is a laser application that can be processed.

The first is a regular contract job that comes from a shop that needs laser processing. These companies are not interested in acquiring laser capability for themselves and prefer to simply buy the service as needed.

A second scenario that Laser Services encounters is pre-production evaluation of a design to test market acceptance or manufacturability. Prototype work usually falls in here.

In a third type of situation, a customer sometimes may contract with Laser Services to evaluate laser processing against another process under consideration. This R&D type of activity is a significant amount of the contract business that comes into Laser Services.

Fourth, occasionally a shop that may have ordered a laser machine tool finds the delivery or implementation delayed to a point where a job's contract fulfillment is jeopardized. They may use another laser job shop to process the order until the in-house capability is on-line.

A fifth scenario is a shop that buys a laser machine but contracts with a job shop to run it for them. Although rare, it does happen. MMS