There are many causes for failure in plastic parts. These can cause a variety of problems too. Here are some common root causes:
- part was originally designed to be made from metal.
- part may have design flaws due to stress concentrations and creep.
- chemical interactions; in fact, even when a plastic may not be affected by a chemical under low stress, it may be susceptible in higher stress scenarios (environmental stress cracking or ESC).
- poor decisions when utilizing material substitution and additives.
- manufacturing process, or lack of control thereof.
With all of these common causes for the failure of plastic parts, one might wonder how does one maneuver the design and process mine field. It is important to traverse these issues since a failure in plastic parts can cause lose of valuable time, materials, customers, and can even lead to litigation. One important tool a company can use to combat and prevent such failure is making sure the engineering education of employees is up to the task for designing plastic parts and/or their molds. It is also important to seek out experienced processors who have the knowledge base required for successful part making. Of course, even when everything is done right, problems may still arise. This is where experience in process and design can be the difference between quickly correcting issues or getting stuck without any support.
Source: Fighting Failure in Plastics by Michael Tolinski – Plastics Engineering July/August 2009