Over the past several decades, thermoplastics have become increasingly popular across industries. Thermoplastic welding allows manufacturers to create complex, intricate joints in thermoplastic components with durable molecular bonds that are more reliable and effective than more traditional mechanical fasteners and adhesives. Welded components can be joined into a single product quickly and efficiently, creating a long-lived weld that is both strong and dependable.
At Plastic Design, Inc., we provide reliable, innovative plastic material solutions for our customers in various critical industries, including medical and biomedical devices, pharmaceutical process equipment, microelectronics, and photonics. Using only the latest in automated technology, we design and manufacture complex and specialty components and products that meet even the most stringent industry standards. We have the knowledge and equipment necessary to complete projects in a timely and highly cost-effective manner.
What are Thermoplastics?
Thermoplastics are synthetic plastics that can be melted, shaped, and cooled to form specific design shapes. Thermoplastics can undergo repeated melting and cooling processes, whereas thermoset plastics only set once and burn when exposed to heat after setting. Many thermoplastics are available on the market, each with unique features that make it useful for particular products and applications. Some of the most popular thermoplastics include:
A lightweight ethylene polymer resin, polyethylene has a variable crystalline structure that makes it highly versatile. It is inexpensive, chemical resistant, and available in high- and low-density formulations for use in everything from medical implements to plastic bags.
Multiple propylene monomers combine to create polypropylene, a rigid and inflexible semicrystalline thermoplastic that is ideal for packaging, medical implements, and low-friction components.
Polyvinyl chloride (PVC)
Designers and manufacturers value PVC for its chemical resistance and toughness. This polymerized synthetic resin made from vinyl chloride sees frequent use in pipes and fixtures, construction supplies, medical devices, electronics, and automotive components.
Polystyrene is a synthetic polymer composed of styrene monomers and available in foam and solid forms. Solid polystyrene is transparent and hard, often used in food and pharmaceutical packaging, medical equipment, and laboratory equipment.
Acrylic is a lightweight, highly transparent thermoplastic often used as a more durable alternative to glass in industrial, medical, retail, and other applications.
Nylon is a smooth thermoplastic composed of synthetic polyamide polymers. This highly versatile material creates threads, fabrics, ropes, and solid shapes.
Plastic Welding Techniques
Thermoplastics feature compatibility with various heat treatments, and a variety of plastic welding techniques harness this quality. Some of the most common thermoplastic welding techniques include:
Friction welding generates heat by rubbing two parts together at a specific speed. Friction-generated heat melts both parts’ edges, and pressure holds them together until they solidify into a single joined part.
Extruded-bead seal welding (extrusion welding)
Extrusion welding is ideal for large and thick components that require a longer weld. A welding rod softens the plastic in an extruder. The extruder forces the softened plastic onto the parts being joined, which have also been softened using hot air jets. The extruded plastic bonds to the softened surfaces, creating a strong bond.
High-frequency welding uses high-frequency electromagnetic waves to generate heat within specific polymers. The process is highly localized and facilitates long, continuous welds between parts without added material.
Hot plate welding
Hot plate welding — also known as hot tool welding — incorporates heated tools shaped to match the joints of the component parts. The heated plates (tools) are applied to the ends of the parts to be welded. Once melted, the ends get pressed together until the joint cools and creates a bond.
Hot gas welding
Hot gas welding – also called hot air welding — features a welder with a plastic filler rod. The welder emits a hot jet of air or gas to soften both the filler material and the surfaces being joined together. The plastic filler material must be similar to or the same as the component material to create a sufficient bond.
Laser welding uses a laser to heat the material between the components, causing them to melt and join along the welding line. For this method to be effective, one component must be transmissive and the other absorptive so the laser can pass through the transmissive component and reach the absorptive part at the desired joining point.
Injunction welding uses an electromagnetic current to heat and melt plastics with embedded carbon fiber, metal, or other conductive materials. This process is particularly useful for reinforced materials used in the aerospace industry.
Solvent welding uses specialized solvent chemicals to dissolve the thermoplastic material, allowing the polymer chains from both components to combine with each other and create a solid bond.
Ultrasonic welding uses high-frequency vibrations to generate friction heat between the component parts. This extremely fast welding technique can be used with almost any thermoplastic.
Similar to friction welding, spin welding uses friction generated by one component spinning against a stationary component. Once the material between the two has melted, the spinning component is stopped and held against the stationary component until the plastic has cooled, forming a solid bond.
Benefits of Plastic Welding
Plastic welding offers numerous benefits over other bonding techniques, including:
- Cost-effective. Plastic welding does not require extra solvents, uses very little energy, and cycles quickly for increased productivity and lower overhead costs per unit.
- Fast and clean. Plastic welding does not present a weld flash, making it an extremely safe, quick, and easy process. The end product presents a clean appearance, with nearly invisible or seamless lines.
- Highly versatile. Plastic welding can be used on components of almost any size, shape, and configuration, and completes high- or low-volume orders with speed and precision.
- Permanent. Plastic welding creates a permanent molecular bond between the welded components for a highly dependable joint.
- Works with almost all thermoplastics. Plastic welding can be used on almost any thermoplastic polymer, even most thermally-sensitive plastics.
Quality Plastic Welding by Plastic Design, Inc.
At Plastic Design, Inc., we are dedicated to providing our customers with the highest quality thermoplastic welding services in the industry. With more than 40 years of experience in the design and fabrication of specialty plastic components for critical industries, we understand that every project has unique requirements. Whether you need plastic prototypes for a new medical device or a full production run for a custom automotive component, Plastic Design, Inc., has the knowledge, skills, and equipment necessary to produce components quickly and efficiently within your budget. In addition to state-of-the-art welding services, our 30,000-square-foot IPCA 620 and ISO 9001:2015-certified facility features CNC machining that allows us to provide a variety of milling, drilling, and boring services.