Plastic Welding Services
Contact welding
This plastic welding method is the same as spot welding except that heat is supplied with convection of the pincher tips instead of electrical conduction. Two plastic parts are brought together where heated tips pinch them, melting and joining the parts in the process.
Hot plate welding
Related to contact welding, hot plate welding is used to weld larger parts, or parts that have a complex weld joint geometry. The two parts to be welded are placed in the tooling attached to the two opposing platens of a press. A hot plate, with a shape that matches the weld joint geometry of the parts to be welded, is moved in position between the two parts. The two opposing platens move the parts into contact with the hot plate until the heat softens the interfaces to the melting point of the plastic. When this condition is achieved the hot plate is removed, and the parts are pressed together and held until the weld joint cools and re solidifies to create a permanent bond.
High frequency plastic welding
Certain plastics with chemical dipoles, such as polyvinyl chloride (PVC), polyamides (PA) and acetates can be heated with high frequency electromagnetic waves. High frequency plastic welding uses this property to soften the plastics for joining. The heating can be localized, and the process can be continuous. Also known as Dielectric Sealing, R.F. (Radio Frequency) Heat Sealing. This is the same concept as induction plastic welding.
Ultrasonic plastic welding
In ultrasonic plastic welding, high frequency (15 kHz to 40 kHz ) low amplitude vibration is used to create heat by way of friction between the materials to be joined. The interface of the two parts is specially designed to concentrate the energy for the maximum weld strength. Ultrasonic plastic welding creates a strong uniform bond.
Vibration or friction welding
In vibration or friction plastic welding, the two parts to be assembled are rubbed together at a lower frequency (typically 100-300 Hz) and higher amplitude (typically 1-2 mm) than ultrasonic welding. The friction caused by the vibration motion combined with the clamping pressure between the two plastic parts creates the heat to melt the contact interface between the two parts, and results in a strong plastic welding bond. At the completion of the vibration motion, the parts remain held together until the weld joint cools and the melted plastic re solidifies. The friction movement can be linear or orbital, and the joint design of the two parts has to allow this movement.
Plastic Spin welding
Plastic spin welding is another form of frictional welding. With this process, one part is held stationary, while the other one is rotated at high velocity. The rotating part is then pressed against the fixed part with significant force. The plastic spin welding process is related to vibration welding.
Laser welding
This plastic welding technique requires one part to be transmissive to a laser beam and either the other part absorptive or a coating at the interface to be absorptive to the beam. The two plastic parts are put under pressure while the laser beam moves along the joining line. The beam passes through the first part and is absorbed by the other one or the coating to generate enough heat to soften the interface creating a permanent weld.
Semiconductor diode lasers are typically used in plastic welding. Wavelengths in the range of 808nm to 980nm can be used in the welding of various plastic material combinations. Power levels from less than 1W to 100W are needed depending on the materials, thickness and desired process speed.
Diode laser systems have the following advantages when welding plastic materials:
- Cleaner than adhesive plastic bonding
- No micro-nozzles to get clogged
- No liquid or fumes to affect surface finish
- No consumables
- Higher throughput
- Can access work-piece in challenging geometry
- High level of process control
Requirements for high strength laser welded plastic joints include:
- Adequate transmission through upper layer
- Absorption by lower layer
- Material compatibility - wetting
- Good joint design - clamping pressure, joint area
- Lower power density
Plastic materials that can be joined by laser welding include:
- Polypropylene
- Polycarbonate
- Acrylic
- Nylon
- ABS
Specific laser plastic welding applications include sealing / welding / joining of: catheter bags, medical containers, automobile remote control keys, heart pacemaker casings, syringe tamper evident joints, headlight or tail-light assemblies, pump housings, and cellular phone parts.
Solvent welding
In solvent plastic welding, a solvent is applied which can temporarily dissolve the polymer at room temperature. When this occurs, the polymer chains are free to move in the liquid and can entangle with other similarly dissolved chains in the other component. Given sufficient time, the solvent will permeate through the polymer and out into the environment, so that the chains lose their mobility. This leaves a solid mass of entangled polymer chains which constitutes a solvent weld.
Plastic spin welding top & bottom together to create this filter |
 Hot plate welding small gas tank |
 Hot plate welding large gas tank |
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 Sonic Welding cap so seal off tube. |
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