Archive: Feb 2021

The Pipe Fusion Welding Process

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Pipe fusion welding is used for many applications across a wide range of industries. At Plastic Design, Inc., we offer a variety of plastic welding services, including numerous pipe fusion welding capabilities. Our state-of-the-art 30,000-square-foot facility combined with over 40 years of experience grants us the resources and capabilities to perform top-quality welds while meeting strict industry standards.

There are many different methods of pipe fusion welding, each of which has its own unique process and specific uses. To determine which option is best for your application, it is important to understand the distinctions between each method.

What is Pipe Fusion Welding?

Pipe fusion welding is an umbrella term that includes several types of methods and procedures. In general, pipe fusion welding involves the process of joining two plastic pipes through the use of heat and various types of fusion welding machines. During the process, heat is applied to prepared pipe ends, which are then pushed together with enough force to create a permanent bond.

Pipe fusion welding is compatible with a wide range of materials, including high density polyethylene (HDPE), polyethylene (PE), polypropylene (PP), and more. When selecting the proper pipe fusion method, it is important to consider factors such as the application, materials, and required bond strength.

Methods of Pipe Fusion Welding

There are several methods of pipe fusion welding, each of which uses different equipment and procedures to complete the weld. These methods include:

Electrofusion Welding

Electrofusion welding is a type of resistive implant welding used to connect pipes. Fittings implanted with metal coils are placed around joints to prepare them for welding. An electric current travels through the coils, heating and melting the plastic pipe in the process to form a joint. Electrofusion is one of the most efficient welding methods, using various built-in electric heating components and special fittings to create a consistent weld. It’s particularly useful in applications requiring on-site welding or welds in tight spaces.

Butt Fusion Welding

Butt fusion welding is one of the most popular fusion welding methods for joining PP and HDPE pipes, either for attaching fittings to them or to form a continuous run. In butt fusion welding, two ends of the pipes undergo heating and welding through the use of a butt welding machine. Pipe ends are pressed against a heating plate for a specific period of time, and then they are pushed against each other at a designated pressure. HDPE and PP are ideal materials for this process, as they form joints that do not leak.

Saddle Fusion Welding

Saddle or sidewall fusion welding is used for connecting saddles to the sides of pipes. The process works by heating the exterior surface of the pipe and the compatible surface of the fitting. A saddle fusion welding machine is used to help facilitate proper heating, force control, and alignment for an accurate weld. Once joined, the weld area is cooled and the weld is completed.

Socket Fusion Welding

When working with injection-molded fittings, socket fusion welding is a common choice. A socket fusion tool, which contains a metal socket heater and a spigot fitting, aligns and heats the appropriate locations of each component to fuse them in a single joining operation. While the metal socket heater heats the exterior of the pipe, the spigot fitting heats the interior of the injection-molded fitting. Once heated for the proper amount of time, the heated tooling is removed, and the fitting and pipe are pushed together to form a bond.

Pipe Fusion Welding from Plastic Design, Inc.

There are many methods of pipe fusion welding, and it’s important to choose the right one for your application. At Plastic Design, Inc. our team of plastic welding experts can help you determine which method is best for your needs. As a trusted provider of plastic welding services, we ensure high-quality welds on even the most intricate joint lines. To learn more about our pipe fusion welding capabilities, or to get started on your plastic welding solution, request a quote or contact us today.

Guide to Thermoplastic Welding

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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:

Polyethylene (PE)

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.

Polypropylene (PP)

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 (PS)

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

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

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

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.

Induction welding

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

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

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.

Spin welding

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.

To learn more about our comprehensive thermoplastic welding and fabrication services, contact our experts today or request a quote.

What You Need to Know About Extrusion Welding

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At Plastic Design Inc., we specialize in the manufacture of plastic products and systems. Armed with extensive manufacturing experience and state-of-the-art manufacturing equipment, we have what it takes to deliver solutions to customers in some of the most demanding industries.

We offer turnkey solutions—including design, fabrication, and on-site support services—to ensure the product or system we provide fully meets the customer’s specifications and standards. One of our core plastic manufacturing capabilities is extrusion welding.

What Is Extrusion Welding?

Extrusion welding is a manufacturing method used to join thermoplastic and composite materials. It relies on the use of a specialized welding machine to heat and melt plastic filler material and heat the base material to prepare it for welding. The molten filler material is then extruded onto the heated base material. After both materials have cooled, they remain permanently bonded to each other.

This joining process is generally used to produce larger and thicker fabrications, such as tanks and pipes made from materials greater than 6 mm in thickness. It allows for the production of long and consistent welded seams in a single pass, which translates to shorter processing times and, consequently, lower processing costs.

Advantages of Extrusion Welding

Compared to other joining methods, extrusion welding has many advantages, such as stronger bonds, faster processing times, cleaner welds, and broad versatility. Depending on the equipment utilized, the process can also offer other advantages. For example, extrusion welding equipment with screw-based extruder components:

Eliminates air pockets and scraping requirements

Plastic extrusion welders with screw-based extruders grind up the filler material as it is heated. This process reduces the risk of air pockets forming in the material and ruining a weld. It also eliminates the need for machine operators to manually scrape the material to remove oxidation and other surface contaminants that may interfere with the welding process. Altogether, this results in better weld quality and shorter weld times.

Allows for more uniform temperature distribution

Since the screw extruder grinds up the filler material as it passes through the barrel, the material heats up more evenly. This quality allows for the formation of more consistent welds.

Maintains a more even extrusion rate

Screw extruders offer a more even material flow rate than non-screw extruders, which reduces the risk of the slipping material as it is extruded and, consequently, the risk of forming an uneven weld.

Applications of Extrusion Welding

Plastic extrusion welding plays a role in the manufacture of a wide range of plastic components, such as fume hoods, ducts and fittings, and tanks. Experienced plastic welders, such as the experts at Plastic Design, can achieve and maintain high precision in extrusion welding operations. This ability allows them to produce parts and products suitable for highly technical fields, such as:

Extrusion Welding From Plastic Design, Inc.

Extrusion welding is used to create plastic components for a variety of industries. If you’re looking for quality extrusion welded plastic components, turn to the experts at Plastic Design. Customers in some of the most highly technical fields have trusted us to produce products and systems for their critical applications for over 40 years. To learn more about our extrusion welding capabilities, contact us today. To discuss your project requirements with one of our team members, request a quote.