Welding joints, also called communal areas, are created when thermoplastic materials are bonded using heat generation. The plastic edges are typically heated to meet them and meld them together.
It is possible to weld plastics using a three-phase surface preparation, heat application, and cooling.
PMMA, polycarbonate, polyethylene, polypropylene, polyethylene terephthalate and polyvinyl chloride (PVC) are several plastics that can be welded.
Other factors to consider include welding equipment, plastic welding rods, extruders, heating and cooling times, pressure, and many others. When the weld joint is heated, devices hold the plastics components together to allow a complete bond to form as the heat is applied to the weld joint.
For joining plastic pieces, as well as for repairing cracks, plastic welding is used.
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Plastic welding – what is it all about?
People automatically think of welding as joining two pieces of metal together. But metal is not the only material that can be welded together. Joining two thermoplastics at the molecule level is known as plastic welding. Like metal welding, plastic welding involves pressing together the materialising it and then cooling it. Due to its cooling strength in joints, plastic welding is commonly used in vehicle repair. It is possible to weld plastic in numerous ways, each with unique advantages.
Using Welding Processes on Plastics
The following is a list of different welding processes used to join plastics.
A Laser Beam Weld (LBW) is a laser beam welding process.
Using a laser, this welding technique joins thermoplastic pieces. It is also known as Laser Beam Welding (LBW). When the two parts are being welded, the laser beam produces a concentrated source of heat that allows narrow and deep welding at high speeds.
Two of its many advantages are speed and precise control.
Welding with ultrasonic technology
For a long time, ultrasound plastic welding has been a popular method. The thermoplastics are joined using high-frequency mechanical motion and heat. Electrical signals are converted into automated signals by converting high-frequency energy. You can weld almost any plastic material with ultrasonic welding. Ultrasonic welding is known for being clean, affordable, and high-quality.
Hot Gas Welding
Hot gas welding was used to manufacture smaller items (heat exchangers, chemical and water tanks, etc.). Specially designed heat guns were used for this welding process.
Upon firing the gun, stifling air softens the plastic parts to be welded and the plastic filler rod, which must be made from the same or similar plastic material as the parts to be welded. As well as the hot gas, a plastic filler material is also added to the weld joint to facilitate bonding.
Spin Welding
Using surface friction to create a circular weld joint, spin welding joins plastic components. One-part spins relative to the other, making the heat needed to melt the surfaces. During the process, a controlled load is applied to the parts. After the spinning has stopped, a cooling process is initiated.
It is possible to weld large plastic parts in this way, which is fast. However, at least one part must be circular. Containers can be sealed with this technology.
Plastic molding
The plastic is molded into a specified shape as the heated, pliable workpiece cools and hardens. Plastic molding techniques are numerous. Some of them are:
Moulding by injection. Custom injection molding is helpful for applications requiring a high melt index, such as dishware production. Using plastic resin injected into molds, it is possible to produce mass products at a low cost. During injection molding, melted plastic is injected around another part. Over molding, insert molding, and two-shot molding are variations in this process.
Blow molding. Bottles and fuel tanks are often made using blow molding. An expanded plastic bubble creates a hollow center in the mold instead of simply injecting liquid plastic into it. The added step creates a more accurate image and an open center. After hitting the cool mold, the plastic solidifies into the desired form.
Rotational molding. A hollow plastic product made via rotational molding includes canoes, toys, buoys, and automotive parts. A mold is sealed with un melted plastic, then heated and rotated to cover the interior thoroughly and evenly. Even though it does not produce uniform walls as precisely as other methods, it is suitable for larger, more complex products.
Reaction Injection Molding (RIM). Plastics used for RIM, such as polyurethane, can only be melted once. A chemical reaction combines two different polymers inside a mold, and the product is then hardened. The RIM can produce large parts, insert moldings, and varying wall thicknesses in one piece. The tooling costs can also be reduced.
Compression molding. Heat is used to compress plastic powder or pellets into the desired shape. Plastic thermoforming, discussed below, is like this. The powder or pellet is often heated and compressed to form a “biscuit”.
Processes for Fabricating Plastics
When choosing a plastic fabrication process, consider both the product’s functionality and ease of manufacture. Some methods of fabricating plastic are inefficient, so they will not be helpful for your project. Among other things to consider are:
Plastic compounds versus single plastics
The material proportion between plastics and non-plastics in the product
As an adhesion, lamination, or base material, plastic plays a crucial role in your fabrication process.
A final product’s size and application.
Plastic fabrication’s advantages and disadvantages
Advantages of plastic fabrications
Compared with other fabrication methods, such as metal, plastic fabrication offers numerous advantages. Additionally, it is highly efficient and simple. Among the benefits are:
Forming is simple
The melting point of plastic is lower than that of other popular materials. Plastic offers relative ease of creating complex geometries because of its low melting point and good malleability.
Coating or coloring a plastic part is possible before fabricating it. As a result, the color additives will be mixed with the pallets or granules, so the effort in finishing is significantly reduced, particularly in mass production.
Production is faster
Moulding and shaping plastic take a short amount of time, which reduces the production cycle. Cycle time is directly proportional to lead time and production rate.
Light Weight
Lightweight plastics have revolutionized the fabrication industry because of their specific properties. Compared to metal, they are lighter and perform better. Plastic fabrication has become more prevalent in many industries.
Chemical Resistant
Chemical reactions can damage plastics less than metals. Plastics are less prone to oxidation and reduction. They will therefore be more chemically resistant.
Disadvantages of plastic fabrication
Even though plastic is the perfect material for all fabrications, this is not the case. Plastic fabrication has some disadvantages, just like every coin has a dark side.
Resistant to limited temperatures
The resistance of plastic to higher temperatures is exceptionally low. Elevated temperatures can quickly melt or deform them.
Limitation of wear resistance
Additionally, plastics are not very resistant to acids or corrosive elements. If corrosive materials encounter them, they can lose their structural integrity.
Structural Weakness
Even though plastic is commonly used for parts that need a prominent level of strength, it is not structurally sound. Heavy equipment parts and building structures should not be made of plastic.
Non-Degradable
Unlike most organic materials, plastics usually do not degrade once they are disposed of. It is becoming more common to discard plastic products within a fleeting period after purchase, and this may be causing landfill space to be a concern.
Conclusion
Industries have been significantly impacted by plastic fabrication. Thermoplastics and thermosetting plastics are used in countless applications, including windows and doors, pipe systems, filtration systems, chemical feeders, ventilation systems, and chemical storage. Plastic fabrication is used in the Automotive, aerospace, and construction industries, so if you think your sector needs a custom plastic fabrication service, contact us!
