1. © Pearson & GNU Su-Jin Kim Welding & Joining Manufacturing Processes Plasma arc welding A concentrated plasma arc is produced and directed toward the weld area. Higher quality and speed than the TIG. Plasma AW http://www.youtube.com/watch?v=jo376zPns8I

2. © Pearson & GNU Su-Jin Kim Welding & Joining Manufacturing Processes Plasma cutting http://www.youtube.com/watch?v=mJJydOxHwZU&feature=results_main&pla ynext=1&list=PL8EE6E5350B31D89B Negative electrode Cutting gas - + Shielding gas Plasma channel Positive metal Plasma: gas -(heat)> plasma ( +ions + -electrons ) Focused stream of plasma cut sheet metal. Cutting speed ≈ efficiency, power / thickness, specific heat, melting point : v ≈ η P / (t w c Tm)

3. © Pearson & GNU Su-Jin Kim Welding & Joining Manufacturing Processes Electron-beam Welding Kinetic energy of high-velocity electrons is converted into heat to strike the workpiece. The higher the vacuum the more the beam will be able to penetrate the part and the greater depth-to-width ratio. http://www.youtube.com/watch?v=NONurFigP5I

4. © Pearson & GNU Su-Jin Kim Welding & Joining Manufacturing Processes Laser-beam welding Uses a high-power laser beam as a heat source to produce a fusion weld. Has a high energy density and a deep penetrating capability. http://www.youtube.com/watch?v=51d6gQxg1KI

5. © Pearson & GNU Su-Jin Kim Welding & Joining Manufacturing Processes Laser-beam Cutting http://ma.gnu.ac.kr/vod/Machining/Laser_beam_machining.MP4 High power (kW) laser melts and evaporates material. CO 2 & Nd:YAG lasers are used for industrial cutting. Mirror Xenon Flashlamp Nd:YAG crystal Laser Mirror

6. © Pearson & GNU Su-Jin Kim Welding & Joining Manufacturing Processes Laser Welding Machine Multi axis machine used for laser cutting, welding, marking. http://ma.gnu.ac.kr/vod/Joining/Laser_Welding.wmvhttp://ma.gnu.ac.kr/vod/Joining/Laser_Welding.wmv Machine

7. © Pearson & GNU Su-Jin Kim Welding & Joining Manufacturing Processes Laser-beam Cutting Standard roughness ∝ material thickness / laser power, cutting speed : r ∝ t 0.5 / (P 0.5 v 0.3 ) Cutting rate ≈ laser power / evaporation energy per volume, thickness, width of laser: v ≈ P / (e t w) Laser beam Focusing lens Gas Material w t

8. © Pearson & GNU Su-Jin Kim Welding & Joining Manufacturing Processes Laser drill Non-contact, a wide range of materials, accuracy and consistency, as small as 10 – 20 microns. Aerospace part: http://www.youtube.com/watch?v=83OQTZZ4ML8http://www.youtube.com/watch?v=83OQTZZ4ML8 Glass: http://www.youtube.com/watch?v=CS60VzAkhxkhttp://www.youtube.com/watch?v=CS60VzAkhxk

9. © Pearson & GNU Su-Jin Kim Welding & Joining Manufacturing Processes Resistance Welding( 전기저항용접 ) Welding is produced by means of electrical resistance between 2 joined members. Heat generated is H = heat generated (J) I = current (A) R = resistance in ohms t = time (s)

10. © Pearson & GNU Su-Jin Kim Welding & Joining Manufacturing Processes Resistance Welding Contact resistance of electrode-workpiece < Faying surface resistance of workpiece surface Pressure reduces contact resistance and is increased after solidification for forging Rapid, small heat affected zone, no filler, high reliability, automation possible Mostly lap joint, thickness is limited<12mm, clean interface is needed Difficult to weld high conductivity material (Al, Cu)

11. © Pearson & GNU Su-Jin Kim Welding & Joining Manufacturing Processes Resistance spot welding Tips of the 2 opposing electrodes contact surfaces of lap joint and resistance heating produces a spot weld. Good bond in the weld nugget is obtained by having pressure continually applied till current is turned off. Strength of weld depends on surface roughness and cleanliness of mating surfaces. http://www.youtube.com/watch?v=AwL1CAg43PU&p=9B6D9EAE75875D9D http://ma.gnu.ac.kr/vod/Joining/Resistance_spot_welding_aluminume.MP4

12. © Pearson & GNU Su-Jin Kim Welding & Joining Manufacturing Processes Resistance Welding Resistance Seam Welding Current and pressure is continuous or on-off through rolls Resistance Projection Welding Many welds simultaneously Rolls Plates Electrode

13. © Pearson & GNU Su-Jin Kim Welding & Joining Manufacturing Processes High frequency welding ( 고주파용접 ) High frequency current up to 450 kHz  Localize heat  Forge the joint Used for pipe and structural beam welding Small heat affected zone Highly conductive material can be easily joined (up to 20 mm)