Plastic welding has taken over the consumer production industry because of many reasons. Aside from plastic being a cost-efficient, more flexible choice, it has also proven its durability as a material.
Having plastic welding techniques and methods to reinforce plastic materials for various uses make it all the more relevant in consumer production.
In this post, we look at eight of the most popular and effective techniques and methods in plastic welding. Their advantages are also explored for your reference.
Plastic Welding: What It is and Its Significance in Production
Before anything else, we must lay down what plastic welding is. As a method, plastic welding is popular in plastic part fabrication. Essentially, it is made possible by joining two thermoplastics. In doing so, it is important that the thermoplastics joined are compatible.
After which, the thermoplastics are pressed using various heating techniques. This allows combining proposed joints in one welded product. In the process, continuous pressure application during the heating process is induced.
As a result, molecular bonding occurs between the welded materials. Plastic welding is a common method in electronics, medicine, construction, and consumer production, among others.
According to TWI Global, the following plastic materials are the most commonly used in plastic welding: acrylic, polycarbonate, polyvinyl chloride, and polyethylene, among others.
Plastic welding is significant in production because of its versatility and cost-efficiency. The use of plastic as material and the lack of necessity for post-processing and assembly, are just some of the reasons why it is a cost-efficient production method.
As such, it is a go-to method by manufacturers who are engaged in producing consumer products, applied in various fields.
3 Steps of Welding Plastics
For you to get a bigger picture of what truly happens in plastic welding, here are the following steps that plastic welded products go through. All the sub-steps are already incorporated in each of these steps for a more comprehensive view.
Step 1: Prepare the Working Space and Clean the Plastic Materials
Setting up the work space is crucial for a seamless plastic welding. All obstructions must be eliminated to avoid infirmities in the surface. Most especially, proper ventilation must be present since the operator shall be exposed to high heat and a lot of chemical fumes.
The basic thing to do is to clean the thermoplastics to be used first. It is done by simple water, soap, and thorough drying. If stains are visible in the plastic, you can use paint scraper, sandpaper, or liquid solvents.
Step 2: Clamp the Plastics
To hold the pieces in the desired joint, a clamp and tape are used for the parts to be welded. After which, the plastic pieces to be welded are pinned in the work bench using a C-clamp.
Note however, that there are various ways to clamp or join the plastic depending on the welding technique to be used.
Step 3: Welding and Cooling
Before cooling the welded pieces, you must fix the product to ensure smoothness. At least five minutes is needed for the welded pieces to cool down or for it to reach at least the room temperature. To fix the level of smoothness, you shall need to sand the welded piece.
Most Common Plastic Welding Methods
Knowing the steps in plastic welding is one thing. But knowing that there are various welding methods that are specifically appropriate to use for specific materials is everything.
Depending on the heat requirement, the following are the heating processes in plastic welding. Specifically, here are the most common methods in plastic welding which you should know of.
An enumeration of the pros and cons of each plastic welding method is also presented for your reference.
Ultrasonic Welding
This plastic welding method is one of the most popular in the list. As the term implies, it makes use of high frequency, mechanical vibrations combined with low amplitude. Such vibration joins the plastic polymers together.
On the upside, ultrasonic welding is beneficial because it produces high quality products. It also produces with high and at low turnaround. It is also safer to do, offers high aesthetic value, and is suitable for polyvinyl plastic material.
| Pros | Cons |
|---|---|
| Offers short intervals for production to final product turnaround. | Not suitable for most thermoplastics and plastics with high moisture content. |
| Safer as it does not use direct high heat. | Not suitable for denser, thicker plastics. |
| Applicable to other plastics such as polyvinyl chloride. | Applicable only for overlapping joints. |
| Produces sturdy weld, hence, higher product value. | Involves more processes and materials, hence, slower lead time. |
Laser Welding
As the name suggests, laser welding makes use of a laser beam, thawing the plastic for welding. To make sure that the plastic material is intact and joined strongly, the heat applied must be below the plastic material’s evaporation point.
As a method, laser welding further includes sub-types: single pass, contour, hybrid, and simultaneous. The subtype to use depends on the laser welding machine, the material, and the process speed.
One of the advantages of laser welding is its accuracy and its suitability for more complex designs.
| Pros | Cons |
|---|---|
| Offers concentrated heating, hence, high-end welded parts. | High upfront production costs. |
| Parts may be welded at room temperature. | Not suitable for thicker plastics. |
| Applicable for highly geometric plastic designs. | Improper welding may lead to brittle products. |
| Highly applicable in the field of aerospace and automotive. | |
| Clean looking products with high aesthetic value. |
Friction Welding
This is a unique plastic welding process because it does not require the application of heat. As the term suggests, it is friction which joins the plastic material in the process.
For this to happen, a continuous inducement of friction is applied. This is done by rotating the plastic materials against each other.
The advantages of friction welding include low distortion and warping of the plastic material, does not require consumables, hence, cost-efficient, produces high quality product, and most especially, the process is environment friendly.
| Pros | Cons |
|---|---|
| Oxidants are easy to remove. | High upfront cost. |
| Plastics do not warp or shrink even at low heat. | Selective; only applicable for round bars. |
| Fast welding speed and eco-friendly. | |
| Energy and cost efficiency. | |
| Perfect for the welding of different plastics together. |
High Frequency Welding
This method makes use of an installed electromagnetic field. The material commonly used for this method is plastic polymers. Through high frequency vibration, the electromagnetic field generates high heat. For plastic welding to happen, the operator shall continuously apply pressure until the desired form is welded.
Some of the advantages of high frequency welding include faster welding speed, smaller thermal influence range, and lesser splitting. On the downside, it diffuses a lot of heat which is detrimental to the operator.
| Pros | Cons |
|---|---|
| Heat influence on the production process is low. | Not very safe; emits high heat. |
| Offers faster welding and lead time. | Heating area may be smaller compared to other methods. |
| Not prone to splitting during the welding process. |
Vibration Welding
The process employed in vibration welding is quite like friction welding. The reason for this is that in vibration welding, the plastic parts to be welded are rubbed against each other but at a specific amplitude and frequency.
There are two main types of vibration welding: linear and orbital vibration welding. The difference between the two is the motion to which the vibration moves.
On the upside, vibration welding is cost-efficient because it does not require consumables, does not require that high heat, and there is also no need for surface preparation. Furthermore, it is suitable for irregular shaped plastics and in welding thin plastics.
| Pros | Cons |
|---|---|
| Cost-efficient; does not need consumables for welding. | Requires flat and/or horizontal working space. |
| Energy-efficient. | Required equipment needs high capital. |
| Work space preparation is not necessary. | Only suitable to a limited range of materials. |
| Applicable to irregularly shaped and very thin plastics. |
Hot Plate Welding
As the term suggests, this method employs heating a welding plate where the parts are welded together. After welding, the pieces are left to cool, hence, permeating a molecular bond for the pieces to be more intact and durable.
This is quite a tricky method because it requires high precision, skill, and timing. While suitable for an array of plastic types, it is most suitable for semi-crystalline and soft thermoplastics as well as larger plastics. Its advantage includes short turnaround, and produces durable welded materials.
| Pros | Cons |
|---|---|
| Cost-efficient; does not need consumables for welding. | Requires flat and/or horizontal working space. |
| Energy-efficient. | Required equipment needs high capital. |
| Work space preparation is not necessary. | Only suitable to a limited range of materials. |
| Applicable to irregularly shaped and very thin plastics. |
Hot Gas Welding
This is the more traditional type of welding. It makes use of a handheld welding gun which blows high heat to weld polymers, metals, and other materials. This is most applicable in the fabrication of containers, heat exchangers, tanks, and pipes.
Although not a very modern welding method, it still comes with various benefits. Some of these include high portability, does not require high-end tools, does not require a high level of technical skill, and most of all, does not need electricity.
| Pros | Cons |
|---|---|
| Produces some of the strongest welded joints. | Requires high maintenance equipment. |
| Applicable to large to very large plastics. | Not suitable for very thin plastics. |
| Offers shorter cycle time compared to other methods. |
Spin Welding
This is also called rotational friction welding. It is specifically used in welding thermoplastics with surfaces that are rotationally symmetric.
The method employs the rubbing of the materials under high pressure and in a uniform circular motion. The rubbing itself creates the needed heat for the welding to take place.
On the upside, spin welding does not require that much technical skills. It is also very energy-efficient, does not need consumables, and is a compatible welding method for all types of plastics.
| Pros | Cons |
|---|---|
| Portable and easy to operate. | Slower process. |
| Very cost and energy efficient. | Takes longer time for the desired temperature to be met. |
| Requires minimal labor. | Not applicable for thick plastics. |
Benefits of Plastic Welding in Production
In a day and age where high-end production tools and equipment have taken over, producers still cling to plastic welding.
Because of this, it is imperative to know some of the benefits one could get from plastic welding. As such, here are the benefits that producers and manufacturers can reap from plastic welding.
No Additional Consumables
Plastic welding is very cost-efficient because it does not require additional consumables. Consumables come in the form of clamps, fasteners, glues, and solvents.
They ensure that the parts to be welded together are intact all throughout the process. In plastic welding, such is no longer needed, thus, lesser risks on the part of the operator and lesser production costs.
Compatible With Any Joint Shape
Plastic welding is also compatible with any joint shape. This is because there are a lot of plastic welding techniques and methods that you could use for more complex shapes. So, regardless if you are working with complex shapes or not, you can depend on welding techniques.
No Workspace Ventilation Needed
A common misnomer is that all welding techniques exhaust dangerous fumes. That is not always the case. There are more plastic welding techniques that do not produce harmful fumes. As such, the need for a ventilation environment is not needed for some plastic welding techniques.
Cost-Effective
As have been said, plastic welding is a very cost-effective option. Aside from the methods no longer need consumables, it is also energy-efficient as it only depends on vibrations and friction, low cycle time in heating and pressing also makes plastic welding a cost-effective option.
Versatility in Welding Choice
Since plastic welding is suitable for different shapes, and materials of various sizes and dimensions, plastic welding is truly a highly versatile welding choice. The only thing needed here is to choose the best type of plastic welding technique for the plastic material that you have.
Lightweight Production
Plastic welding does not require rivets, consumables, and fasteners. All of these contribute to the overall weight of the product. Because these are not needed in plastic welding, plastic welding is lighter compared to the use of mechanical fasteners.
The Weld is Permanent
Compared to other methods which need adhesives for the pieces to be molded together, welding itself is a permanent method.
If you are one who does not know how to check the internal integrity of the parts to be molded together, welding makes the joining permanent without having to check the internal components of the materials.
Where Are Welded Parts Used?: Applications of Plastic Welded Parts
Since plastic welding is cost-efficient and highly beneficial, it is normal to be curious as to where it is applied. The following are the most common industries where plastic welded parts are needed.
Aeronautics
The lightweight feature of welded plastics along with accurate production without damaging or compromising internal components make plastic welded products very beneficial for the aeronautics field. As is the case, tanks, trays, and holding panels of aircrafts are made from plastic welded pieces.
Agriculture
Plastic welded parts are also applicable in modern agriculture. PVC fencing, tanks, gaskets, and misters, all benefit from the methods used in plastic welding.
Automotive
In the field of automotive, plastic welded materials are very popular. Their durability, heat and chemical resistance make them viable in the automotive industry.
Some of the most common automotive parts that are produced through plastic welding are battery cases, grills, radiators, bumpers, wheel liners, and more.
Marine
Aside from the applicability of plastic welding parts in aeronautics and automotive fields, the marine industry also benefits from the method.
Boats, tanks, holding wells, and other fishing equipment and tools are made from plastic welding. Plastic is a suitable material in this industry because plastic is resistant to rust and corrosion.
Plumbing
The production of modern series of faucets, drains, pipes, are all made through plastic welding. Most of the parts in plumbing are singly produced.
The others that are produced which need post-assembling benefit in the permanence of the welding process.
Get the Chance to Create Your Custom Plastic Parts
With all things considered, there are various reputable firms and manufacturers which offer plastic welding services. Kemal Manufacturing is one of these reputable manufacturers that can cater to any plastic welding service that you need.
From quotations, consultations, complete list of plastic welding services and more, you can create your plastic parts seamlessly and conveniently at competitive prices with Kemal Manufacturing.
Conclusion
Plastic welding seems to be an underrated method because laymen think that it is confined with just the handgun heat method. But there are different techniques and methods in plastic welding, with indubitable advantages.
Depending on your plastic material, there is a suitable plastic welding method to consider. All you must do is to narrow down the plastic material at hand and explore the best plastic welding method to use.
FAQs
There is also handy information that you might need later when it comes to plastic welding. Hence, here are some plastic welding FAQs for your reference.
References:
https://www.rapiddirect.com/blog/plastic-welding/
https://www.plastivision.org/blog/8-plastic-welding-techniques-for-precise-product-results/
https://nyfast.com/blog/post/75-8-plastic-welding-techniques-methods
https://www.twi-global.com/locations/south-east-asia/faqs/what-is-plastic-welding
https://capablemachining.com/blog/the-ultimate-guide-to-plastic-welding-10-methods-you-need-to-know/
