It is not always obvious how to go about choosing the right high-performance polymers for your custom plastic machining needs. And within the business, there are some stubborn myths about the differences between injected molded and machined fabricated plastic components.
Elements To Consider
First, you need to think about the application of your component to decide which material to use. What temperature will it be required to work at? Will it be exposed to sunlight, chemicals, etc. Then, there are the demands on strength, transparency, and general wear and tear to consider.
Plastics which are melt processible such as PSU, PEI, PPS and PPSU are often chosen for those fabricated plastic components which need to be high grade of polymer.
Other questions to ask are whether the component is to be part of a bearing or a wear element within a structural component. What must its impact resistance be, and so on?
Next, you need to determine the design of the polymer part you will use. This means looking at the design with relation to stiffness, strength, wear resistance, friction, and fatigue resistance.
Then there is the grade to think about, whether your plastic component should be of a glass or carbon-reinforced grade, or a wear grade, with graphite PTFE.
Also, consider the size of the part needed, is it large or does it have a difficult to machine feature? What is the material with the most economical cost for a high level of output? Also, might your design be subject to change before being finalized?
Then we come to the process. This is where it is helpful to ask your supplier about the process of custom plastic machining you will need.
Unfortunately, despite the wide choice of material available, it is not always possible to get the fabric you desire, in every size you might want it.
And as engineers often favor materials with a low viscosity for injection molding, this can lead to financial considerations.
Even now, it is often incorrectly assumed that all fabricated plastic components are automatically cheaper than their metal alternatives.
However, fabricated plastic components can frequently cost more than metal parts to manufacture. In particular, these higher standard of plastics are costly to produce when compared to the raw metal material alternatives.
Where the costs come down are with the manufacturing processes. Injection molding is less expensive than the process of forging a metallic shape. Cost analysis must be applied to the investment needed for making a mold for parts which will be injection molded, also remembering to take into account the entire lifetime of the component manufactured.
Injection molding is both speedy and effective when it comes to making fabricated plastic components, but it still requires an outlay. This may be between AUD1000 to AUD10000 depending.
Making Your Choice
Choosing the right materials for your design takes a high degree of specialism – be sure to select the best material and process for your needs and don’t be afraid to ask questions along the way to ensure your choice is an informed as possible.