It seems so easy to produce a good plastic weld. But, is it really so, or are there some hidden failures that might occur that nobody is able to recognize? Well, an expert can probably tell a good weld from a bad weld. When you know what kind of failures can occur, you will have a better understanding of plastic welding and what constitutes a good or a bad plastic joint. As I mentioned in previous articles, there are several things to consider before you start welding. As a reminder, I would like to briefly go over some important considerations or, if you missed my previous articles (which can be found at www.plasticsmag.com), use this as a start.
First, there are two primary groups of plastics, thermosets which are not weldable, and thermoplastics which generally are weldable. Don't try to weld thermosets, they won't melt. Basically, different thermoplastics cannot be welded together. Only the same materials can be welded successfully. Use caution with Polyamides (a common trade name is Nylon) or Polyurethanes.