Tham khảo tài liệu 'process selection - from design to manufacture part 10', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Plasma Arc Welding PAW 209 Plasma arc spraying melting of solid feedstock . powder wire or rod and propelling the molten material onto a substrate to alter its surface properties such as wear resistance or oxidation protection. Filler rod sizes between and mm typically. Economic considerations Weld rates vary from min for manual welding to 3m min for automated systems. Alternative to TIG for high automation potential using key hole mode. Welding circuit and system more complex than TIG. Additional controls needed for plasma arc and filters and deionizers for cooling water mean more frequent maintenance and additional costs. Economical for low production runs. Can be used for one-offs. Tooling costs low to moderate. Equipment costs generally high. Direct labor costs moderate. Finishing costs low. Typical applications Engine components Sheet-metal fabrication Domestic appliances Instrumentation devices Pipes Design aspects Design complexity high. Typical joint designs possible using PAW butt lap fillet and edge see Appendix B - Weld Joint Configurations . Design joints using minimum amount of weld . intermittent runs and simple or straight contours wherever possible. Balance the welds around the fabrication s neutral axis. Distortion can be reduced by designing symmetry in parts to be welded along weld lines. The fabrication sequence should be examined with respect to the above. Design parts to give access to the joint area for vision filler rods cleaning etc. Sufficient edge distances should be designed for. Avoid welds meeting at end of runs. Mostly for horizontal welding but can also perform vertical welding using higher shielding gas flow rates. Filler can be added to the leading edge of the weld pool using a rod but not necessary for thin sections. Minimum sheet thickness mm. Maximum thickness commonly Aluminum 3mm Copper and refractory metals 6 mm Steels 10 mm Titanium alloys 13 mm Nickel 15 mm. Multiple weld runs required on sheet .
