PETG welding
Frequently asked questions about PETG welding
What is Polyethylene Glycol Terephthalate?
PETG is a thermoplastic material with an amorphous or unorganized structure. Thermoplastic because it has the ability to harden and soften according to the temperature at which it is heated, making it eminently recyclable. Amorphous because it is composed of molecular chains that are neither aligned nor ordered, it is characterized by its light color or even transparency.
Derived from Polyethylene Terephthalate (PETG), which is widely used in the production of “plastic” bottles, PETG is based on the same polymer backbone to which Cyclohexane Dimethanol has been added, resulting in a modification of the molecular structure. Indeed, the size of the building blocks increases (6 additional carbon atoms) and there is no longer any integration into neighboring molecular chains, unlike with Ethylene Glycol. This interferes with crystallization and lowers the polymer’s melting point, giving it its amorphous character.
What are the characteristics of PETG?
The molecular structure of Polyethylene Glycol Terephthalate gives it the following physicochemical characteristics:
- high level of translucency (up to 90%),
- smooth, shiny surface,
- impact resistance even at low temperatures,
- operating temperature from – 40 to + 65%,
- ductility (capacity for deformation without breaking),
- thermal insulation properties,
- resistance to acidic and basic chemical environments,
- corrosion resistance to oxidizing agents.
PETG can be given the following characteristics through the use of specific additives or treatments:
- protection against ultraviolet degradation (UV stabilization),
- food compatibility,
- structured exterior,
- limitation of thickness-dependent reflection,
- improved fire resistance,
- reduction of smoke development.
What does PETG look like?
Depending on its intended use and production stages, Polyethylene glycol terephthalate can take on different forms:
- transparent or colored filaments that can be reinforced with carbon fibers for 3D printing,
- powder for Selective Laser Sintering,
- translucent granules for PETG extrusion,
- film reels for thermoforming,
- plates of various sizes for laser cutting or cold bending,
- semi-finished products (blister packs, components, etc.) for assembly or finishing operations.
How is PETG manufactured?
Like its predecessor Polyethylene Terephthalate, Polyethylene Terephthalate Glycol can be used for a wide range of manufacturing operations:
- linjection molding,
- extrusion blow molding,
- cold and hot bending
- drilling and milling,
- mechanical or automatic sawing,
- laser or motorized cutting,
- hot forming,
- engraving or laser marking,
- decoration by printing,
- manual or automated welding,
- etc…
What are the uses of Polyethylene Glycol Terephthalate?
The technical characteristics of PETG mean that it can be used for a wide range of purposes in several sectors of activity:
- The protective shells, food caps, blisters, collars and bottles for cosmetics packaging.
- display cases and storage containers for the food industry.
- POP displays, signs and illuminated panels or decorative labels in the field of communication.
- Cycling, climbing and caving helmets to protect both amateur and professional athletes.
- Photo frames, display cases for collections and interior glazing for decoration and layout.
- orthopedic parts, medical devices and health protection masks for the healthcare sector.
- plastic toys (characters, miniatures, models, game boxes, dice and other play accessories).
- Molds for confectionery (sweets, lollipops, berlingots, caramels, etc.) and chocolate-making.
- Protective equipment for industry (machine tool casings and covers ).
- etc…
How is PETG welded?
The use of various welding techniques of Polyethylene Glycol Terephthalate (PEG) parts or elements enables manual or automated assembly of all types of products or packaging.
PETG is hand-welded using a Polyethylene Glycol Terephthalate rod, which is heated alternately with the edges of the two parts to be joined. This addition of material creates a weld bead between the touching edges of the two parts, which will have at least the same strength.
PETG welding can also be carried out semi-automatically or even fully automatically using the following technologies:
- The high-frequency welds are made using special welding machines equipped with electrodes, which diffuse a 27.12 MHz electromagnetic current into the areas to be joined created by their own generators. The instantaneous melting of materials held under pressure, and subjected to this high-frequency field, enables connections to be made that are sharp, clean and solid after cooling.
- Ultrasonic welding is performed using specialized welding presses, which operate according to the following principle : the generation of an electric current with a frequency of 20 to 70 kHz by an electromagnetic transducer. The ultrasound thus generated is transmitted via a welding head or sonotrode to the materials to be joined. This enables solid welds to be produced by melting the touching ends.
