Plastics Welding

Key takeaways

• Plastics welding joins thermoplastic materials by applying heat and pressure, creating a bond that can be as strong as the original material.
• Different plastics welding methods, such as hot gas welding, ultrasonic welding, and extrusion welding, are used depending on the material, geometry, and application requirements.
• In high-purity and industrial environments, plastics welding must be carefully controlled to prevent contamination, leaks, or structural weaknesses.
• Proper material selection, surface preparation, and operator technique play a major role in achieving consistent plastics welding results.
• When performed by experienced fabricators using the right process controls, plastics welding supports durable, leak-tight assemblies used in industries such as semiconductor manufacturing, chemical processing, and life sciences.

Some engineers automatically think of metal when it comes to welding, but plastics welding grows in popularity every year. Manufacturers in all tiers regularly make the switch from metal to plastics welding. A plastics welding process represents the molecular bond between two compatible plastics.

A superior plastic weld provides first-rate strength, and finished welds are long-lasting, meaning any necessary replacements and/or repairs will occur in the distant future. One way plastics welding proves superior to steel weldments is that chemicals can corrode and contaminate metal, severely decreasing its usefulness in certain applications.

Plastics welding produces durable, reliable, and complex transportation, monitoring, and purification systems. Plastic welders can perform pipe-to-pipe weldments that meet your exact requirements. Plastics welding is a complex process that requires the right set of skills and a strong passion for improving those skills. Plastic welders require significant dexterity and mobility. There is no formal education for plastics welding—you learn best on the job and gain expertise with years of training and working with the various types of plastics used in welding.

Plastics Welding: The Process

Producing plastics welding involves three main steps:

Surface Preparation

First, a technician will examine each plastic component for defects. The plastic components are cleaned and/or abraded. This can be a time-consuming task, though it is required to achieve top-quality results. Performing surface preparation thoroughly reduces oxidation of the plastic and helps eliminate potential contaminants like dirt. Any contaminants may negatively affect the final quality of the welded plastic.

Heat Welding

There are several ways to weld plastic. Heat is a commonly used option. Chemical solvents are another option for plastics welding, depending on the type of plastics being melded together.

Heat increases the malleability of plastic. Steam, hot gas, a welding rod, a laser, or a hot plate heats the plastic. Hot gas welding, aka heat fusion or butt welding, is a common practice that works effectively.

While the plastic components are pliable, they go into a vise, where pressure applies to the pieces, causing bonding on the edges of the plastic. Applying consistent pressure ensures the quality and integrity of a weld.

A highly effective thermoplastic welding process uses nitrogen and heat when joining two polymer-based products, resulting in a stable, strong plastic weld.

Plastic Weld Cooling

After the heating stage, the plastic weld cools. Cooling is a necessary step for solidifying the bond between two plastics. The strength of a finished weld depends on how the plastic cools. Pressure applied during the cooling step assists in shape retention. Without pressure during cooling, the material may shrink and alter the shape of the product, negatively affecting the results.

Plastic Weld Uses in Manufacturing

Many industries currently require the use of volatile chemicals, including alternative energy, chemical manufacturing, life science, semiconductor, and medical device manufacturers. One of the biggest challenges they face is creating complex components with miniature segments through which liquids and gases can easily pass. Plastics welding is a top solution for manufacturing those components for safety purposes and to ensure a longer lifespan of the product. Plastics welding is used to construct patient-monitoring devices, diagnostic instruments, and machinery used in life-saving operations.

Plastic piping kits provide gas or liquid transportation from one area of a system to another in one clean, clear shot. This allows simple transport around components and other obstacles in the system with a smooth inner bore. Tubing assemblies reduce potential leak areas along the way or remove areas where liquids could hang up and cause contamination.

Plastic Pipe Welding Keeps Your Production Running

Axenics welds thermoplastics, including fluoropolymers, in tighter tolerances than our competitors can achieve. Versatile thermoplastics are ideal for durable, long-lasting welds. Many plastics deteriorate slower than metals, which lends our plastic pipe welding results staying power.

Welding with perfluoroalkoxy (PFA) is one of Axenics’ specialties. We work with different tiers of manufacturing in the semiconductor chip industry, and those customers’ production systems benefit from low-friction PFA. The plastic is easily formable and offers a super-strong resistance to many chemicals. PFA’s stability also holds up in varying temperature environments, making it the ideal solution for delivery systems where hot or cold harsh chemicals need to flow through seamlessly.

PFA Pipe is Flexible for Multiple Configurations

The process of welding PFA pipe into different configurations with a variety of T’s and elbows allows our customers easy access for plugging a manifold into their system with just two end connections rather than multiple.

This process reduces potential leak areas. Using T’s, elbows, and other weldable fittings/components also allows them to branch and angle their transportation system in different directions and into tighter tolerances. Space is often a major concern when updating production systems, and plastic pipe welding offers a lot of flexibility for fitting components into a working production area.

Plastics Welding Benefits

Plastics welding is often a faster and simpler fabrication process versus welding with metals because plastics are generally lighter in weight than many metals. Plastics are also a wise choice for maintaining the safety and reliability of your end product as they are more chemically resistant than most metals.

• A plastic weld has a strong resistance to acids, alkalis, greases, and solvents, hydrogen peroxide, demineralized water, and hot steam.
• A plastic weld offers a minimal release of gas under vacuum, which helps maintain a sterile environment.
• Plastic welds have a strong plasma resistance reducing the possibility of corrosion.
• Plastic welds resist thermal degradation and maintain high operating strength and rigidity in high temperatures.
• A plastic weld offers the benefits of good creep and chemical resistance, minimal thermal expansion, and good wear resistance.

Axenics’ in-house plastic experts have decades of experience innovating thermoplastic welding and bending techniques. There’s virtually no limit on the length of thermoplastic pipe we can weld and bend for your production, and no limit on the complexity or number of welds.

The Difference Between Butt Weld and Socket Weld

Socket Welding

In socket welding, the male pipe fits into a female fitting. The process involves heating the pipe’s exterior and the fitting’s interior before bonding them together. As the material cools, a solid, permanent connection forms.

Socket welding at Axenics is typically machine-driven, although hand welds are used for projects with specific dimensional requirements. A small internal lip forms during this process, creating a strong bond but with a slight material overlap.

Butt Welding vs. Socket Welding

With traditional butt welding, two flat ends of pipe are heated and bonded together, forming a bead inside the pipe where they connect. While effective, this bead can trap chemicals and disrupt flow in certain applications.

Axenics employs bead- and crevice-free equipment for butt welds, eliminating the internal bead and ensuring a smooth, flawless weld. Our proprietary technique requires no filler material or back welding, providing superior results for high-purity systems.

Why Choose Axenics for Plastics Welding?

Axenics offers additional plastics welding services, such as fabricating thermoplastic frames for chemical engineering transport systems. Using computer numeric controlled (CNC) routers, we precisely cut plastic frame components to meet customer specifications.

We specialize in welding fluoropolymers, which are highly resistant to heat and chemicals. These materials can endure exposure to harsh acids that would destroy metal tanks, ensuring long-lasting, reliable systems.

Axenics’ decades of expertise in thermoplastic welding and bending allow us to tackle projects of any complexity. From intricate subsystems to long, seamless thermoplastic piping, our goal remains constant: delivering transportation systems with consistent, reliable flow.

Understanding Plastic Bonding

It’s important to note that two completely different plastics cannot be bonded. However, plastics with a similar chemical makeup can be perfectly welded, ensuring durability and functionality for your specific application. For engineers evaluating butt weld vs socket weld options, Axenics provides the expertise, equipment, and materials to deliver exceptional results tailored to your industry needs.

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