Welding Plastics: Methods, Materials and Key Considerations
We work with plastics on a daily basis and know that welding is a vital part of many manufacturing processes. But which methods work best, and which materials are suitable for welding? Here, we go through the most common methods for welding plastics, as well as discussing material properties and common problems that may arise.
Metoder för svetsning av plast
There are various methods for welding plastic, but the most common are hot-gas welding, extruder welding and friction welding. Hot-gas welding uses a gas flame to heat the plastic to its melting point, after which it is shaped and joined. Extruder welding uses an extruder to melt and shape the plastic, whilst friction welding uses pressure and friction to melt and join the plastic.
Vi har erfarenhet av att arbeta med dessa metoder och ser att varmgassvetsning är en av de mest flexibla. Men vilka material kan svetsas med denna metod?
Material som lämpar sig för svetsning
Några av de material som passar bäst för svetsning är PE-HD, PE-1000, PP och PVC. Dessa material har en relativt låg smältpunkt och är därför lättare att svetsa. PVDF är ett annat material som kan svetsas, men det kräver högre temperatur och noggrann kontroll av processen.
Men vad händer om vi försöker svetsa material som POM C eller PTFE? Dessa material är svåra att svetsa på grund av deras höga smältpunkt och låga förmåga att binda till varandra. PTFE kan faktiskt inte svetsas alls, på grund av sin extremt låga friktionskoefficient och höga smältpunkt.
Varför är vissa material så svåra att svetsa? Det finns saker som kan göras för att förbättra svetsbarheten, till exempel att använda en annan svetsmetod eller att tillsätta en svetsförbättrande komponent till materialet.
Förberedelse av fogar
An important part of welding is the preparation of the joints. It is important that they are clean and dry, and that they are the correct shape and size to be joined together. We often use a joint cutter to cut the joints to size, and then we clean them with a brush and cleaning fluid.
If the joints are not properly prepared, this can result in poor-quality welds and joints that do not hold up over time. It can also lead to damage to the material, or the weld not being strong enough.
Testing welds
Once the weld is complete, it is important to test it to ensure it is of a good standard. We often use a combination of visual and mechanical tests to check the quality of the weld. We examine the appearance of the weld and check that it is straight and even. We also test the strength of the weld by subjecting it to stress and seeing if it holds up.
If the weld is not up to standard, it may need to be redone or repaired. In some cases, it may be necessary to replace the entire piece of material.
Common faults that can occur
There are several common faults that can occur during welding. One common fault is that the weld becomes too hot, which can result in damage to the material or the weld not being strong enough. Another common fault is that the weld becomes too cold, which can result in the weld not being strong enough.
We have also observed that the weld can become porous, which can result in it not being strong enough. This may be because the material does not have the correct properties, or because the welding process has not been carried out correctly.
When welding is better than gluing
Ibland är svetsning att föredra framför limning. Svetsning är ofta bättre när materialet är tjockt, eller när svetsningen behöver vara mycket stark. Limning kan vara bättre när materialet är tunt, eller när limmet är starkare än svetsningen.
If we cannot decide whether to weld or glue, it may be a good idea to try both methods and see which works best.
Welding plastic is a complex process that requires precision and experience. With the right materials, the right method and the right preparation, the weld can turn out very well. Do you have any questions or concerns about welding plastic? Please feel free to contact us!
Would you like to discuss your requirements for welded plastic components?
Svetsa plast: Metoder, material och viktiga aspekter