Plastic Assembly

Depending on the plastic materials being welded, one of several plastic welding methods can be used. Ultrasonic welding, hot air welding, infrared welding, friction welding, spin welding and laser welding are popular methods in industrial manufacturing. Most of these methods can be performed manually or via automated systems.

Plastic welding is a category of fabrication techniques that joins two separate pieces of plastic by fusing them together at the molecular level. There are many different methods of welding plastics together, varying by the plastic materials and connection shapes at hand. In general, plastic welding uses heat, force or chemical reactions to soften and fuse separate objects together.    

Ultrasonic welding is a joining method that utilizes high-frequency vibrations transmitted into specific plastic or metal components, fusing them together at the molecular level. These vibrations are emitted by a sonotrode at frequencies between 15kHz and 70kHz: high enough to induce localized melting of the separate materials together, but in a very precise and well-controlled manner. The vibrations induce friction between materials, which in turn create just enough heat to melt and intermingle the separate materials together. Once cooled, the weld joint is fully formed.

Due to the friction during the Ultrasonic welding process, debris can sometimes form around the welding areas. Materials that are less brittle and have lower melting points often produce little to no debris, whereas parts made of brittle materials with complex joint geometries can produce debris or flash.

While part of the answer depends on what component is in question, generally speaking, ultrasonic plastic welding is the ideal choice for joining two plastic components of the same materials. Plastic welding can form stronger, longer lasting bonds than adhesives, often at a lower cost per joint (since you’re not purchasing consumable glue materials). That said, some light-duty trim, cosmetic and fabric components will be better suited to gluing for simplicity and cost reasons. We suggest contacting us to review and advise on the best solution for your application. 

A wide array of plastic and metal materials can be ultrasonically welded. Thermoplastics with a crystalline molecular structure are the most common choices, including acrylonitrile butadiene styrene (ABS), polyphenylene oxide (PPO), polystyrene (GPPS) and polyethylene (PE). Metallic choices include soft metals such as aluminum, copper and brass.

Ultrasonic welding uses vibration to melt the molecular structures of separate materials together into a single piece. As such, the molecular structures of materials being fused together must be both very similar and structurally compatible, not to mention that they must melt and cool at approximately the same temperature range. While sonic welding of a metallic material into a separate plastic material is possible in some cases, this is usually not a commercially viable fabrication method.

Joining plastic components together using ultrasonic welding is a very reliable, cost-effective fabrication technique used widely in industrial manufacturing. Sonic welding is the preferred joining method for countless medical, automotive, consumer goods, electronics and packaging applications.

Compatible, non-structural plastic materials can be optimally joined using ultrasonic welding. This fabrication method uses a vibrating horn (or sonotrode) to transmit physical, mechanical oscillations into plastic materials, melting them together until they form a solid bond.

Ultrasonic welding thermoplastics can be highly successful when welding two materials of the same plastic material. However, in some cases, ultrasonic welding can also be viable for welding two different materials together. These dissimilar plastics must have compatible molecular structures and melting temperatures, determined through testing to ensure their weldability. Ultrasonic frequencies and clamp pressures must also be determined for each application. When in doubt, contact us to confirm compatibility of your different plastic materials.

We will work closely with you from product concept stages through production. Along the way, we’ll refine your process to achieve the best plastic assembly results. Our services include concept sketches, prototypes, testing, formal CAD drawings, production tooling and complete systems installation and startup support. Count on us to help you select the best plastic materials and develop the optimum welding joint design, too. We test every solution in our on-site application development lab. 

Trust AMS and our proven 17-step process to deliver your project on time and within budget. You won’t be kept in the dark: As a true partner, we update you every step of the way with frequent and consistent communication. Make AMS your first-choice plastic assembly partner today.

Automated plastic assembly machines we design and build for clients include:

• Heat staking machines
• Ultrasonic sealing machines
• Continuous ultrasonic welding

Clients use their AMS machines for:

• Ultrasonic spot welding
• Ultrasonic plastic welding
• Textile welding
• Welding plastic
• Ultrasonic welding polyurethane
• Ultrasonic welding horn design
• Ultrasonic welding temperature

If you’re searching for plastic joining processes such as spot welders, spin welders, or other welding plastic technologies, contact us for a complimentary application review.