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Armed with a variety of lasers with wavelengths from the IR through the UV, and pulse lengths from milliseconds to femtoseconds, applications can be addressed in automotive manufacturing, semicon- ductors, microelectronics, medical devices, alterna- tive energy, aerospace and defense. All materials can be addressed by using the right laser and optical setup with the stipulation that maximum material thickness is somewhat dependent on the output power of the laser. Hard/brittle materials like ceram- ics and glass have a higher ablation threshold and


pulse widths designed for micro welding; 25–50-W pulsed Nd:YAG lasers are routinely used to seam weld 0.015" (0.381-mm) thick titanium cases for implantable devices. More recently developed fi ber lasers offer excellent fl exibility in tailoring weld dimensions and the best penetration per watt performance that enables high-speed seam welding. A 300-W fi ber laser can seam weld 0.01" (0.25-mm) thick airbag detonator casings at 2 ips (50 mm/s), a 20-W pulsed fi ber laser can produce a 0.001" (0.025 mm) diameter spot weld in 0.001" (0.025-mm) thick foil. The diode laser is an established laser technology that has been used for many plastic welding applica- tions. Welding of plastics with lasers is a growth area.


Laser Macro Welding-High-Power Laser Welding Some general specifi cations and limits of highpower laser welding are weld speeds in the range of 40–350 ipm (1–9 m/min) and weld depths up to 5/8" (16 mm). Lasers have been an industrial tool for longer than 30 years. The laser sources being used for high-power


Laser-drilling systems from Prima Power Laserdyne can precision-drill aircraft turbine engine components with shaped holes on shallow angles to 10º from the surface.


Photos courtesy Prima Power Laserdyne


therefore require higher energy density on target to achieve material removal, while soft materials like polymers generally require less energy density on target to effect clean removal.


Micro Welding With Lasers Laser micro welding generally covers applica- tions with less than 0.04" (1-mm) penetration. This noncontact process for spot and seam welding offers low heat input, tailored weld dimensions, high-speed welding, and a wide range of joint geometries and materials. The foundation and continuing growth of laser micro welding is largely based on medical device manufacture, automotive sensors and airbags, batteries and consumer electronics. Lasers suitable for micro welding are pulsed


Nd:YAG, fi ber and diode. The pulsed Nd:YAG laser has the largest install base with peak powers and


LF8 AdvancedManufacturing.org


laser welding before 2003 were CO2 and fl ash lamp pumped CW YAG lasers. Since 2003, diode-based lasers have taken over the majority share of this industrial laser market seg-


ment. This is due to the commercial benefi ts of these diode-based products, such as smaller size, reduced power use and decreased maintenance, and improved optical and delivery characteristics. There are several types, including fi ber lasers, disk lasers and fi ber deliv- ered direct diode.


Most often, laser welding is done autogenously,


and part fi t-up and fi xturing are key elements. For diffi cult material combinations, poor part fi t-up, and welds with deeper penetration than autogenous meth- ods permit, hybrid welding is used. Methods include the addition of cold or hot wire with laser. Benefi ts of the fi ber and disk lasers include easy integration with robots and good beam quality, which allows the use of long focal lengths and remote welding. High-power laser welding is used by aerospace, automotive, mining, construction, and agriculture.


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