|It is important to determine which types of plastic polymers are ultrasonically weldable prior to starting your product or project. There are a couple of different types of plastic polymers, but not all of them are weldable: |
1) Thermoset polymers which are not ultrasonically weldable.
2) Thermoplastic polymers which are ultrasonically weldable.
Thermoplastic polymers which are ultrasonically weldable consist of two different types:
1) Amorphous plastics
b) Semi-crystalline plastics
Some examples of Amorphous Plastics are:
1) Acrylonitrile butadiene styrene (ABS) – ABS is a common thermoplastic polymer typically used for injection molding applications. This engineering plastic is popular due to its low production cost and the ease with which the material can be ultrasonically welded.
2) Polycarbonate (PC) – Polycarbonates are a group of thermoplastic polymers containing carbonate groups in their chemical structures. Polycarbonates used in engineering are strong, tough materials, and some grades are optically transparent. They are easily worked, molded, and thermoformed and are often used in eye wear because it protects the eye from UV light.
3) Polystyrene (PS) – Polystyrene is a synthetic aromatic hydrocarbon polymer made from the monomer known as styrene. Polystyrene can be solid or foamed. General-purpose polystyrene is clear, hard, and rather brittle. It is an inexpensive resin per unit weight. It is a rather poor barrier to oxygen and water vapor and has a relatively low melting point. It is widely employed in the food-service industry as rigid trays and containers, disposable eating utensils, and foamed cups, plates, and bowls.
Some examples of Semi-crystalline Plastics are:
1) Polypropylene (PP) – Polypropylene, also known as polypropene is produced via chain-growth polymerization from the monomer propylene. Polypropylene belongs to the group of polyolefins and is partially crystalline and non-polar. PP is used in a variety of applications including plastic parts for the automotive, aerospace, medical industries, as well as consumer packaging for consumer products.Non woven polypropylene fabric has a variety of uses for many varied applications. It is a cost effective fabric that can be bonded together by ultrasonic welding.
2) High-density polyethylene (HDPE) – High-density polyethylene or polyethylene high-density is a produced from the monomer ethylene. It is sometimes called “alkathene” or “polythene” when used for HDPE pipes. With a high strength-to-density ratio, HDPE is used in the production of plastic bottles, corrosion-resistant piping, geomembranes, and plastic lumber.
3) Polyamide (PA) – A polyamide is a macromolecule with repeating units linked by amide bonds. Polyamides can be made through step-growth polymerization or solid-phase synthesis yielding materials such as nylons, aramids, and sodium poly.
4) Polyoxymethylene, Polyacetal, Polyformaldehyde, or Acetal (POM) – Polyoxymethylene is an engineering thermoplastic used in precision parts requiring high stiffness, low friction, and excellent dimensional stability.