Plastics are regularly used to replace tough, expensive metals such as bronze, aluminium, and stainless steel in numerous applications. This is because plastic can offer a longer part life, reduce wear, corrosion resistance, and near or total elimination of lubrication. The key to effective engineering plastic products is making the right decisions during the pre-production process. These decisions will ultimately determine how useful the plastic product will be. There are six factors to consider during the decision-making process.
The first factor to consider is what the plastic product will be used for. Will it be a bearing and wear application or a structural application? Determining the primary function of the engineered plastic product will help identify what group of materials should be used during production.
The second factor to consider is the thermal requirements of the application. It is a good idea to look at both the typical and extreme conditions it will be used in. This ensures the plastic part will not unexpectedly fail under extreme conditions. When engineering plastic products, the heat resistance will be characterized by its heat deflection temperature and the continuous service temperature.
The third factor to consider is the chemicals which will be used to clean it. Chemical compatibility information is critical to consider because certain plastics have diminished lifespans in aggressive chemical environments. Many plastics suitable for industrial environments, such as Nylon, do not perform as well when exposed to harsh chemicals on a consistent basis.
The fourth factor to consider is in any additional material characteristics when engineering a plastic product. This can include tensile elongation, tensile impact strength, and water absorption. Certain industries must meet specific regulations or guidelines related to material usage. Any of these regulations may affect the material characteristics as well.
The fifth factor to consider is cost-effectiveness. Cost-effectiveness will not only be tied to the materials used when engineering a plastic product but also the shape of the final product. The shape of the object will largely determine what type of manufacturing or production process is the best. The most common options include extrusion, casting, compression moulding, and injection moulding.
Finally, the sixth factor to consider is the machinability of the materials used should be considered. Glass and carbon reinforced plastics can be significantly more abrasive on tooling while also being more notch sensitive during machining than their unfilled counterparts.