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