TWI Frequently asked questions
Many uses can be found for laser technology in microjoining applications. The use of lasers to enable small parts to be machined in silicon for sensors found in a vehicle, is growing. Copper vapour lasers are well suited to this task.The characteristics of the laser weld, including low heat distortion as well as ease of manipulation of the laser beam, are beneficial to the fabrication of small parts; although smaller power ranges (50-300W) are required for theseapplications.
The laser energy can be guided into restricted access areas, where other joining techniques cannot be used. Nd:YAG lasers are routinely used to produce welds between similar and dissimilar materials. They can produce mechanicaljoints, as well as hermetic seals between materials. Lasers can also be used as a source of thermal energy to reflow solders. In this instance, a diode laser may allow better process control than an Nd:YAG laser because of the moreefficient absorption of the laser energy by the solder.
The importance of laser soldering is now becoming apparent with the proposed removal of lead from solders. The replacement solder materials have higher reflow temperatures, that could result in damage to the parts being soldered.Lasers allow the application of heat to the solder joint only, decreasing the risk of thermal damage to the surrounding parts. Typical applications of lasers include the joining of lead frames, light bulb filaments.
Copyright by TWI, 1999
