| Some ultrasonic welding help - plastics ultrasonic welding guide |
| The process of ultrasonic welding of plastics is achieved by applying
a vibrating metal tool (horn) at 90° to the stationery plastic
parts which then vibrate. When combined with pressure, friction
produces heat & melts the parts at the horn contact point. Once
cooled down a solid homogeneous weld between the 2 parts is created. The ultrasonic welding guide below gives you a little ultrasonic welding help by listing the most common unfilled grades of plastic available & their suitability for each style of ultrasonic welding As a rule, stiffer materials are easier to weld & those with higher melt temperatures need more energy. To weld different materials, they need similar molecular structures - crystalline ones are only weldable to themselves |
|
MATERIAL
TYPES, ABBREVIATIONS & STRUCTURES |
CLOSE WELDING |
DISTANT WELDING |
INSERTING |
SPOT WELDING |
STAKING | ||
|
Acetal Co/Homopolymer |
POM |
C | Good | Fair | Good | Fair | Fair |
|
Acrylic |
PMMA |
A | Good | Fair | Good | Good | Fair |
|
Acrylic-Impact Modified |
PMMA |
A | Fair | Poor | Poor | Fair | Fair |
|
Acrylonitrile Butadiene Styrene |
ABS |
A | V.Good | Good | V.Good | V.Good | V.Good |
|
Cellulose Acetate... |
CA/B/P |
A | Poor | NS | V.Good | Poor | Good |
|
Polyamide 6 & 66 (Nylon) |
PA6 & 66 |
C | Good | Fair | Good | Fair | Fair |
|
Polycarbonate |
PC |
A | Good | Fair | Good | Good | Fair |
|
Polycarbonate/Abs |
PC/ABS |
A | Good | Fair | Good | Good | Good |
|
Polyester-Thermoplastic |
PBT/PET |
C | Good | Fair | Good | Fair | Fair |
|
Polyethylene-Low/High Density |
LD/HDPE |
C | Poor | Poor | Good | Good | Fair |
|
Polyphenylene Oxide |
PPO |
A | V.Good | Good | V.Good | V.Good | V.Good |
|
Polyphenylene Sulphide |
PPS |
C | Good | Fair | Good | Fair | Poor |
|
Polypropylene |
PP |
C | Fair-Poor | Poor | Good | V.Good | V.Good |
|
Polystyrene-General Purpose |
GPPS |
A | V.Good | V.Good | Good | Fair | Fair |
|
Polystyrene-High Impact |
HIPS |
A | Good | Poor | Good | Fair | Fair |
|
Polyvinyl Chloride-Flexible |
PVC |
A | Poor | NS | NS | Poor | NS |
|
Styrene Acrylonitrile... |
SAN/ASA |
A | V.Good | V.Good | Good | Fair | Fair |
| A (Amorphous) = polymers with a random molecular chain structure.
This & their wide softening temperature range enables them to
soften gradually without solidifying quickly, thus making ultrasonic
welding them easy. C (Crystalline) = polymers with an orderly molecular chain structure. This & their sharp melting & solidification points makes them absorb vibrations when solid, thus making ultrasonic welding them more difficult. Close Welding = ultrasonic welding where the horn is applied close to (<6.35mm) the assembly joint - good for welding materials whose low modulus of rigidity dampens vibrations a short distance away from the horn. Distant Welding = ultrasonic welding where the horn is applied away from (>6.35mm) the assembly joint - good for welding materials whose high modulus of elasticity propagates vibrations without dampening them. Inserting = ultrasonic embedding of metal components like inserts into preformed holes in the moulding - provides high strength & speed, no stress build up & reduced moulding cycles. Spot Welding = ultrasonic assembly of parts without premade holes or energy directors - good for large parts Staking = melting and reforming a post on the moulding to mechanically lock dissimilar materials in place - provides short cycles, good appearance & tight assemblies. For more help with plastics for your application (costs, properties etc), please view our material selection guide |
