The Benefits of Plastic Welding

The use of plastic in manufacturing is now extraordinarily common — and with the rise of 3D printed objects, more manufacturers are looking to plastics for their production needs. 

As a result, we're also seeing the increased printing of individual plastics that need to be joined together during the manufacturing process. In cases like these, it's possible to use adhesive bonding or mechanical fastening. These methods, however, can't always create long-lasting and permanent bonds. 

Fortunately, it's possible to use one of the several available plastic welding methods — which can also offer distinct advantages over other bonding techniques — to join different plastic components.

What Is Plastic Welding?

Plastic welding, along with adhesive bonding and mechanical fasteners, is one of the three main methods used to join together plastics. Like metal welding, plastic uses one of several different techniques to permanently bond two plastics at the molecular level. 

Many different types of plastic welding are available. Some of the most commonly used are ultrasonic, laser, hot plate and several different kinds of vibration welding. In each of these different types, energy is applied to the join area — through friction, ultrasonic vibration, laser radiation and so on — melting the plastic. 

Once both plastics have cooled, they are joined together into a single part without the need for adhesive or mechanical fasteners.

When Plastic Welding Is a Better Fit

In some instances, plastic welding will be the best available method for joining together two plastics.

Welding can also provide an alternative to mechanical fasteners when joining plastics that can be difficult to bond with solvent, like certain thermoplastics, fluoropolymers and polyoxymethylene resins — also known as acetal or polyacetal resins.

When welding two different plastics with complex geometries or an unusual bonding angle, solvents and mechanical fasteners won't always be appropriate. Several different types of plastic welding, however, can be used to create welds, even between two components with complex or unwieldy geometry.

It can be challenging to establish a waterproof or air-tight part-to-part seal on a plastic object using adhesive. Mechanical fasteners, obviously, can also be problematic if you need an air-tight seal. In cases like these, plastic welding can provide an alternative.

Welded objects can also be lighter than those joined by other methods. Fasteners — especially those made out of dense materials, like metal — can add a significant amount of weight to a finished product. Because plastic welding doesn't add any mass to the objects, components joined with this method will be lighter than those joined with fasteners.

Other Advantages of Plastic Welding

Plastic welding can also offer some unique benefits that make it a better bonding option, even in situations where fasteners and adhesive bonding may be suitable.

Plastic welding can require less surface preparation of the area that will be bonded compared to adhesive bonding. Some methods of welding will also need no curing time once the process is complete, unlike adhesive bonds, which need time to cure and set. With plastic welding, you also won't need to keep track of your store of bonding consumables — like solvent or individual fasteners. As long as the welder is functional, you'll be able to continue work.

Manufacturers can also use plastic welding to create more aesthetically-appealing bonds. Solvents and mechanical fasteners will almost always be visible on a finished product — and, depending on fastener placement, can make joined plastics less ergonomic or a little less pleasant to hold. With hot air welding, for example, you can create weld seams that are both subtle and air- or water-tight. Laser welding can be used to join complex shapes, creating hardly-visible bonds. 

Welding can also streamline the recycling process for plastic objects, as it's possible to keep an object mono-material. With other joining methods, the addition of a solvent or mechanical fastener of a different substance may require the materials to be separated before it can be recycled. This process often is difficult or impossible for recycling companies — which has led some manufacturers to use plastic welding, rather than metal, in their objects.

Reaping the Benefits of Plastic Welding

The increased use of plastics in manufacturing has made plastics bonding more relevant than ever. While many manufacturers opt to use adhesive bonding or mechanical fasteners to join two plastics, these methods don't always produce suitable bonds. Often, plastic welding is a better option.

Plastic objects welded together can be lighter and easier to recycle. The bonds created by the welding process can also be less apparent and more aesthetically appealing than those produced by adhesive or fasteners.

Megan R. Nichols is a technical writer and blogger who covers manufacturing and industrial automation topics. She regularly contributes to sites like IndustryWeek, MHL Network, and ReadWrite. Follow her on Twitter.

 You can also check out an interesting article on tips to wire a plug for a welder.

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