non-arc welding processes
DESCRIPTION
Introduction. Non-Arc Welding Processes. Resistive heating, chemical reactions, focused light and electrons, sound waves, and friction can also be used to join materials Resistance welding Oxy-Fuel Welding Friction welding (&Solid State) Laser and electron beam welding - PowerPoint PPT PresentationTRANSCRIPT
Non-Arc Welding Processes• Resistive heating, chemical reactions, focused
light and electrons, sound waves, and friction can also be used to join materials– Resistance welding – Oxy-Fuel Welding– Friction welding (&Solid State)– Laser and electron beam welding– Brazing and soldering– Plastics joining– Adhesive bonding
Introduction
Joining Plastics• Polymer - a single
building block (mer) is repeated to form a long chain molecule– Thermoplastic polymers
soften when heated, harden when cooled
• 2-liter bottles
– Thermosetting polymers don’t soften when heated
• Car tires, caulking compound
HH
HH C=C
H H-C-C-H H
··· ···
add H2O2
(Poly)ethylene
Welding of Plastics
Hot Plate, Hot Gas, Infrared• Advantages
– Provide strong joints– Reliable– Used on difficult to join
plastics
• Limitations– Slow– Limited temperature
range
0.1.1.2.5.T23.95.12
Hot Plate, Infrared Welding
Hot plate welding
Welding of Plastics
Hot Gas Welding• Thermoplastics
(hotmelts)– Adhesive is heated
until it softens, then hardens on cooling
• Hot gas softens filler and base material
• Filler is pulled or fed into the joint
Welding of Plastics
Vibration• Advantages
– Speed– Used on many
materials
• Limitations– Size– Requires fixturing– Equipment costly
0.1.1.2.5.T24.95.12
Ultrasonic• Advantages
– Fast– Can spot or seam weld
• Limitations– Equipment complex,
many variables– Only use on small
parts– Cannot weld all
plastics
0.1.1.2.5.T25.95.12