Plastic Design Inc. is a renowned company that specializes in manufacturing plastic systems and products. With our wealth of experience in manufacturing and state-of-the-art machinery, we provide top-notch solutions to clients in various demanding industries. Our comprehensive services encompass design, fabrication, and on-site support, ensuring that the final system or product we deliver is compliant with our customers’ requirements and industry standards. One of our key areas of expertise is thermoplastic extrusion welding.
Understanding Extrusion Welding
Extrusion welding is a manufacturing process used to join thermoplastic and composite materials together. During this process, the base material is heated, preparing it for welding, while the plastic filler material is melted using specialized welding equipment. The molten filler material is then extruded onto the heated base material. This creates a strong and durable bond between the two materials, which remains intact even after cooling.
This welding technique is commonly employed for larger and thicker fabrications, such as tanks and pipes made from materials thicker than 6 mm. It offers the advantage of producing lengthy and reliable welded seams in a single pass, resulting in shorter processing times and lower costs.
The Role of a Thermoplastic Extrusion Welder
A thermoplastic extrusion welder is a machine designed specifically for welding plastics. These machines come in various types, each offering a range of features. Some models feature adjustable output volume and are compatible with a wide selection of plastics, including PVC and HDPE. They also come equipped with a multifunctional panel, allowing users to select the appropriate welding profile for specific materials.
Thermoplastic extrusion welders are particularly useful for welds involving thick sections of material. By producing a high-density and homogeneous seam in a single pass, extrusion welding offers a faster alternative to hot gas welding, while ensuring a stronger fusion weld.
The key components of a thermoplastic extrusion welder include a heating barrel and a screw that delivers the molten plastic to a specially shaped shoe. A hot air blower is used to preheat the weld area. The operator manually steers the extrusion welder, making it ideal for finishing work like tie-ins and cross seams.
The screw-based extrusion heads grind the filler material as it is heated, eliminating the risk of air pockets. This results in more consistent heating and better weld quality. When undertaking a welding project, it is crucial to keep these factors in mind.
Types of Thermoplastic Extrusion Welders
Various types of thermoplastic extrusion welders are available, catering to different welding needs. The joining process in thermoplastic extrusion welding involves heating and pressing two plastic pieces together. The pressing action enhances the flow of melt across the interface, while heating promotes chain diffusion and joining. Cooling then solidifies the newly formed bond, creating high-quality thermoplastic parts. However, certain types of thermoplastic materials may pose challenges in the welding process. Let’s delve into the available options in more detail.
The ultrasonic welding machine is a popular choice for plastic welding. It converts electrical current into mechanical vibrations, transmitting them through a metal tool, or horn, supported by a stationary anvil. This results in intimate contact and a strong welded joint.
Before initiating thermoplastic extrusion welding, surface preparation is essential. Clean the surfaces using MEK or a similar solvent, then groove the substrate to accommodate the welding rod. Cut the end of the rod at a 45-degree angle and set the welder temperature accordingly. An automatic speed tip can be used to assist with this process.
Various types of thermoplastic extrusion welding machines are available for different applications. Some are designed for joining piping, tanks, and geomembrane materials, producing a large volume of homogeneous seams in a single pass. The quality of the extrusion weld depends on the operator’s skill and the materials being joined.
Extrusion welding machines are portable and can bond different plastics thermally. In these machines, a heating chamber is heated to a controlled temperature, and the welding rod is discharged through a Teflon die. Speeds and features vary among the different types of thermoplastic extrusion welding machines.
The popularity of thermoplastic welding is on the rise due to its effectiveness in joining thermoplastic components. It surpasses traditional mechanical fastening methods and allows for intricate joints in thermoplastic components, resulting in long-lasting welds. Moreover, this process facilitates quick and easy joining of components.
There are three main types of thermoplastic extrusion welding machines. Hand-held models are suitable for hobbyists, while larger welding projects require specialized machines. Extrusion welders are primarily designed for large-scale jobs, while other plastic welding machines are suitable for smaller tasks.
Hot air welding is another thermoplastic extrusion welding method that utilizes hot gas or air to soften the plastic parts. A dedicated welding gun is used to generate hot gas, which then softens the plastic filler rod. It is crucial for the filler rod to match or be similar to the component material. This method allows for larger welds in a single pass and is commonly used for joining materials thicker than 6 mm.
To ensure a smooth weld, it is important to preheat the welding shoe before starting the weld. Failure to do so may result in a rough weld. Warming the weld surface with hot air helps prevent defects. Additionally, the weld shoe should be centrally aligned with the weld surface and must not come into contact with the edge of the weld.
Advantages of Extrusion Welding over Hot Gas Welding
Extrusion welding combines high pressure and high heat to produce a superior weld bead. Compared to hot gas welding, extrusion welding yields a stronger and more consistent bond. It is also faster, reducing fabrication time and costs. This technique is particularly well-suited for fabricating large thermoplastic structures.
Extrusion welding offers greater accuracy and precision than hot gas welding, as it does not require as precise positioning of the components. The heat generated during extrusion welding is not wasted, resulting in a more uniform melted surface that does not damage non-stick coatings. Unlike hot gas welding, there is no production of fluff or fine particulates.
Extrusion welding is versatile, allowing for the joining of thermoplastic and composite materials. By utilizing a specialized welding machine, the base material and plastic filler material are melted and bonded together, creating a permanent connection. This method is particularly effective for thicker and larger fabrications, enabling the production of long, seamless welds with fewer passes.
Extrusion welders are highly portable and have fewer moving parts, minimizing wear and extending their service life. They are also lighter and more efficient, reducing excessive bearing stress. The speed of extrusion welding depends on the flow rate of the welding gas, the material thickness, and the size of the PTFE welding shoe.
Hot gas welding is a similar process that requires a filler material. While filler material is necessary for hot gas welding, extrusion welding has the advantage of being able to produce larger welds in a single pass. This method is generally employed for materials thicker than six mm.
Hot gas welding has its drawbacks, including uneven melted films and high distortion. Additionally, it can result in irregularities resembling craters on the joined surface, which may compromise the weld’s strength and the joint’s integrity.
Let’s take a closer look at thermoplastic extrusion welding in action: