Most people immediately imagine someone putting two pieces of metal together when they hear the word "welding." But not only metal can be joined together via welding. Plastic can also be joined through welding. Welding is the molecular connection of two thermoplastic materials. Similar to metal welding, plastic welding involves forcing the materials together, heating them, and cooling them. Plastic welding is quite common in automotive repairs because it offers high levels of material strength in a joint.
There are numerous industrial uses for plastic welding and different methods for doing so. This article covers eight plastic welding techniques utilized in producing parts for the plastic industry, as well as the general procedures for welding plastic parts.
Plastic welding is the joining of two compatible plastics for plastic part fabrication. The process involves preparing the thermoplastic components, pressing them into the desired joints, and heating using different heating methods. However, the heating method will depend on the type. For instance, ultrasonic plastic welding is commonly used for PVC because it avoids direct heating, which causes the material to emit hazardous gasses.
The continuous application of the pressure and cooling process helps it form a molecular bond between the two pieces. As a result, plastic welded joints are strong, unlike other plastic joining techniques like adhesives and riveting. Plastic welding technology has been widely utilized in fields such as building, electronics, and medicine.
It could be challenging to weld two semi-finished plastic resins and manufacture them through injection molding or another procedure. Therefore, regardless of the welding process, this section walks you through the steps for welding plastic.
● Set up the workspace and clean the plastic
Establishing a workspace is the first thing to do. Since most heating methods release hazardous vapors, the workplace needs adequate ventilation. Operators should also put on safety equipment.
To ensure a high-quality welded junction, clean the thermoplastics. Warm water and soap can be used to clean plastics, which should then be dried with a clean, lint-free cloth. Additionally, it is advised that you use a paint scraper, 80-grit sandpaper, or liquid solvents like Methyl Ethyl Ketone (MEK) to remove stains.
To create and maintain the ideal junction, clamp, and tape the two plastic pieces together. Set the plastic parts on a workbench and secure them with C-clamps. The welding procedure determines how the plastic is joined. Ultrasonic welding, for instance, is only appropriate for lap joints.
● Finalize the Weld
Before the weld cools, address problems like smoothness. Allow the welded plastic to cool or reach room temperature for about five minutes. The welded junction should be smoothed using various surface finishing techniques or sanding after cooling.
There are several methods of plastic welding, and they all depend on the heating process. These are the top eight types of plastic welding used in the plastic manufacturing industry:
This welding method is also known as Laser Beam Welding (LBW). It uses a laser to join thermoplastic pieces. When the two components are under pressure, the laser beam's concentrated heat source enables narrow, deep welds at high welding rates. Speed and control are some of their numerous advantages.
Ultrasonic welding is an approach that is usually used and has been around for a while. The thermoplastics are joined using heat produced by high-frequency mechanical motion. High-frequency electrical energy is converted into a high-frequency mechanical movement to make this happen. Almost all plastic materials can be joined together with ultrasonic welding. It is renowned for being reasonably priced, spotless, and upholding quality standards.
Hot gas welding uses a specifically built heat gun, a widely used welding technique for producing smaller products (such as heat exchangers, chemical and water tanks, etc.). The hot air produced by the gun softens the plastic components that need to be welded and the plastic filler rod, which must be made of the same or a similar plastic substance. To help in bonding, a plastic filler material is added to the weld junction along with the hot gas.
Spin welding uses surface friction concentrated in a circular weld junction to attach plastic components. By spinning one of the pieces with the other, heat is generated to cause the surfaces to melt and become one. A regulated load is used to hold the two pieces together. After the joint stops spinning, it will be left to cool.
It is a quick process that may be used to weld significant plastic components. However, one of the parts must be circular. One of its applications is container sealers.
It is also known as friction or linear welding. It involves welding two plastic components together under high tension. When vibration is employed at the common interface, heat is produced. It is quicker and more precise than hot plate welding.
This thermal welding method is one of the oldest processes used in joining thermoplastics. A hot metal plate is put against or close to two surfaces, and the surfaces are then joined under pressure to melt them. This technique is widely employed in the mass production of massive constructions like plastic pipes with large diameters since it is straightforward and generates strong connections in nearly all thermoplastics.
It has been around for a while, but friction welding of thermoplastics is usually used to join injection-molded components. Friction is used to create heat and join two pieces together. Friction welding is also used in the aerospace and automotive industries to join metals and plastics because it has many advantages for manufacturing.
This method of joining plastic components is also referred to as high-frequency welding or radio-frequency welding. It employs an electromagnetic field. The high-frequency electric fields are used to heat the material, and pressure is also supplied to soften and connect the two materials, resulting in a strong bond. Polyurethane and PVC are welded with this technology
Plastic welding has numerous advantages and is essential in rapid prototyping and other industries. Here are a few benefits:
The method works with components of any shape. The ability to work with complex shapes is made possible by advancements in various welding procedures. As a result, welding pieces with curved or irregular shapes are simple.
Some plastic welding methods, including vibration-based welding, don't result in fuses. Consequently, there is less requirement for safety equipment and ventilation-related infrastructure.
Plastic welding requires low consumable costs and low cycle times. As a result, it is superior to other joining techniques like riveting.
In contrast to adhesives or other plastic connecting methods, the welded joint is irreversible. It is a reasonable option if you don't want the integrity of the internal component to be compromised.
Several industries can use plastic welding. These are some of the industries that use the plastic welding method:
The method can create boats, ballast tanks, fish-holding wells, water-holding tanks, and other plastic-welded maritime equipment. Plastic is used in the marine environment because of its corrosion resistance and other qualities.
Aerospace polymers demand precision permanent welding that doesn't affect their characteristics. As a result, the method is appropriate for producing plastic welded components such as interior panels, holding tanks, and trays.
The connecting of plastics in the construction of grills, radiators, battery boxes, tire well liners, bumpers, etc., is accomplished by plastic welding.
Plumbing Plastic welding is widely used to construct DWV pipes, drains, faucets, and other plumbing fixtures. These components are made separately and require assembly. Welding is popular because it is permanent, unlike other plastic joining techniques.
Agricultural Plastic welded parts have several uses in agriculture, including gaskets, PVC fencing, tanks, and water and misting lines.
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Plastic polymers play a significant role in the production of products, and plastic welding makes it simple for a product producer to improve designs while speeding up assembly. We've covered the eight different types of welding processes in this article. Are you in need of top-notch plastic welding? Contact Ares Prototyping ama let's get started.
