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This is an abbreviated version of the original work. For full technical details, please consult the original paper.

Laser welding systems have been actively used in the North American jewelry marketplace since 1992. An alternative to soldering or micro-plasma welding, laser welders have gained industry acceptance for their wide range of uses and ability to produce stronger connections with a high level of accuracy, resulting in a significant savings in time, labor and materials.

Laser technology produces a sharply focused light beam that melts a very small area of metal and can be used to join similar or dissimilar alloys.  Laser welding differs greatly from traditional electronic resistance welding. The resistance welding process takes time, leaves scars or blemishes at the weld point and requires specially shaped electrodes to weld hard-to-reach areas.

Sharp, focused laser light beams allow for rapid melting and cooling of similar or dissimilar alloys. The welding process can be performed extremely quickly (normally in milliseconds) and does not scar or blemish the welding surface, hence eliminating the need for acid baths. Since very little heat is generated at the weld point, users can easily weld .5 to 1.0 mm away from the most complicated and intricate jewelry pieces, and because no electrodes or contact points are required, the laser's light beam offers precise welding of complex and difficult-to-reach jewelry pieces.  The laser also enables operators to add additional alloy to jewelry pieces where needed. The weld resulting from this laser operation is considerably stronger than a solder joint.

In addition, laser welding leaves no seams or markings after cleaning or finishing
processes. Eliminating the solder material from the welding process maintains the integrity of the alloy and provides superior strength characteristics when evaluated under most bend test stress evaluations.  Also, the cosmetic appearance of the finished jewelry piece is generally superior to soldering. Added benefits include the reduced cost of materials such as expensive solder compounds.

Jewelry manufacturers currently using laser welders are often amazed at the wide range of applications and ability to produce a higher quality product in less time with fewer materials. Lasers can also be used to re-tip prong settings, repair bezel settings, resize rings, and repair bracelets without removing stones. Sponge-type porosity, normally identified in the final polishing process, can be filled and repaired by using a laser.

How the Laser System Works

One of the key elements in making laser welding applicable to jewelry manufacturing was the development of the "free-moving" concept. In this approach, the laser generates a stationary infra-red light pulse which is targeted through the microscope's cross-hair. The laser pulse can be controlled in size and intensity.  Because the heat generated remains localized, operators can handle jewelry items with their fingers, welding small areas with pin-point accuracy without causing any harm to the operator's fingers or hands. This "free-moving" concept enables users to eliminate costly fixturing devices and increase the range of assembly and repair applications.

Most operators can learn to use laser welding machines in a few hours. An experienced jewelry technician can normally make the transition to manipulating the jewelry item in the laser welding machine within 10 to 15 minutes.  Many laser welding systems come equipped with a color video monitor to assist with training and quality control.

Into the Future

During the last few years, the price of many laser welding systems has decreased, making them more affordable to jewelry manufacturers, small design studios, repair shops, and retail jewelers.  Prices of laser welding systems have stabilized over the last 12 to 18 months, and many lasers are now very competitively priced while offering more features and flexibility for the user. Frequently, those who have purchased the laser systems find that time, labor, and material savings they realized far outweigh the original purchase price. "Laser welders have made our work so much easier that I could not imagine working without one" is a comment often heard from jewelry manufacturers.
When evaluating a laser system's payback timetable, most manufacturers need to consider the following questions:

• •  How is the laser going to improve production output?
  •  By what percentage will the laser reduce scrapped parts or salvage bad castings?
  •  Can the laser allow for more efficient use of labor?
  •  How often will the laser help repair damaged or defective jewelry pieces?
  •  How much money can be saved by reducing the amount of purchased solder material?
  •  Will the laser help in the assembly of complex, difficult to solder jewelry pieces?
  •  Will the laser provide a competitive advantage over the competition?
   

These and many more issues are all important considerations when evaluating the capital investment of a laser welding system. Most manufacturers consider lasers a good investment not only for the short term benefits, but also for its future potential.  Many jewelry manufacturers like the idea of having state-of-the-art technology in their facilities. Laser welding systems will not only enhance the manufacturer's image in the eyes of their clients, but also provide them with the tools and technology required for the future.
 

Making Soldering a Technique of the Past
James E. Gervais
Crafford Precision Products Co.
(CPP)