What is Extrusion Welding

What is Extrusion Welding?

Extrusion welding is the process of welding plastic or other composite materials through a heated automatic or semi-automatic process. 

In the process, a welding head or nozzle is used to push hot air as an extruder pushes filler material out to combine the materials being welded together with the filler material, all forming a Physical bond together. When this happens the base and filler material is heated and then pressed together with plastic needed to bond together through the skillful application of the welder. 

Even more simply put, extrusion welding can be thought of as the process to weld plastics together. It was developed as an evolution of hot gas welding. 

Extrusion Welding Process

1. First the base material is prepared for welding. This is usually two plastic pieces that are welded together, for example two edges for a box we are going to put together. In this first step, we would machine any needed grooves and prepare the material to be welded together. This includes removing any dirt, dust, or other material so that we will have a clean weld put together. 

2. Next, all the welding joints are fitted together and prepped for the welding. This will usually involve utilizing clamps to place the materials together so that they are ready for welding. 

3. Welding then takes place. The extruder feeds material to the body of the extruder and heats it while simultaneously heating the base material. This is where the welder will use the right combination of heat, air, pressure, and extrudate to ensure a stable and well-put together weld. 

4. Adjustments to the weld finish are made. This is where a scraper or any adjustments to both the appearance and the overall welding finish are made. 

5. Lastly, cooling and drying takes place to finish the weld. Once this is done, the clamps are removed, and you’re all set with your finished weld. 

What is Extrusion?

Extrusion is the process where a material is pushed through a die and used for the purpose of combining two cross-sectional materials. Extrusion is a process in which many plastics are combined. In extrusion welding, an extrusion material is used with a welding gun and extruded utilizing heat to create a bond between two plastic pieces. 

The extruded material can be a few different things, but it must be able to bond the base materials well. In addition, there are a few different ways that the extrusion process can work. It can also work with other materials besides plastic, but generally there is a material that is heated and used to help two plastic materials come together through the welding process.  

Getting a Good Weld

To ensure that your project is well put together, there are a few things that you need to keep in mind. Of course, we also recommend a skilled welder who understands extrusion welding well. In general, these factors work together, but you will want to consider: 

• The welding speeding - extrusion welding can be done through an automated process or manually. You will want to consider how fast the weld is being done. Going too fast, the materials could have a poor bond. However, going too fast could use too much material being used and a poor looking weld being done. 

• Temperature of the extrudate - the best temperature will depend on the polymer being used. A skilled welder will generally have a good eye for this. Too hot, and the filler material can break down. Not hot enough, and the extrudate material won’t be able to flow and thus bond with the other materials. 

• Position of the welding head - making sure that the filler material is applied in the right places so that the bond works well together with the material. 

• Airflow rate - how fast the air is being applied to the extrudate and the base materials. This will ensure that the heat is spread evenly, and the bond is consistent throughout.

• Extrusion rate - this is just how much of your third material is being used to apply the bonds to your materials. For example, you want enough extrusion in your joints so that a strong enough bond is formed between your two surface materials.  

Benefits of Extrusion Welding 

Welding has come a long way over the last several years and plastic welding specifically. The main benefits of extrusion welding involve combining plastic in ways not before possible to help businesses and other organizations. 

One benefit of extrusion welding is to efficiently and effectively bond two pieces of plastic together. At Pro Plastic Welding this is done for our clients. A great example of this is working for a laboratory that needs plastic pieces seamlessly put together for their lab. This can be done by creating very effective equipment that helps reduce future time-intensive cleaning tasks. 

In addition, one huge benefit to extrusion welding is saving money on expensive molds for rotational molding or injection molds. If you are in an R&D phase or just building one off assemblies, having a skilled extrusion welder is a benefit to your bottom line. Extrusion welding can produce incredibly strong welds that can be watertight.  

Another benefit to extrusion welding over other welding processes is the ability to weld thicker materials in a single pass. Hot gas or welding with a heat gun and rod typically won't be able to weld thicknesses over ½ inch thick. This would additionally take multiple passes to complete that weld. An experienced extrusion welder operator can weld that same material thickness in a single pass that would exceed the strength of the previously mentioned processes. Pro Plastic Welding has the capability to weld certain plastics up to an inch thick!  

The benefits to extrusion welding are quite numerous. We have created many projects using extrusion welding. You can check out some in our gallery or if you are interested in getting started on a project, you can contact us.