Plastic injection molding
Plastic injection molding is one of the most widely used mass production techniques.
And for good reasons;
it enables the production of parts with complex shapes, and a great number of details. All of this at a low cost price.
On the other hand, investments for this process are relatively high. That is why it is very important to get all the technical details of the parts absolutely spot on.
Aiming for First-time-right is essential; it can save a lot of money and time.
There is a wide range of plastics available, all with their own pros and cons.
Price, looks or mechanical properties. But also resistance to sunlight, to certain chemicals likes petrol or suntan. How they behave in high or low temperatures. Do they stand op to constant pressure? The list goes on and on…
It is quite possible to make robust plastic parts, but it does not come easy.
Compared to metals, plastics are relatively weak. The design margins are small.
We all have, at some point, experienced plastics parts failing on us during normal use. Any improperly dimensioned detail can inadvertently create weak spots that lead to failure. FEM analysis really helps avoid such failures.
Quite often it is very well possible to replace metal parts with plastic parts and save costs.
But a thorough understanding and FEM analysis are essential.
The production process also imposes demands on the design and on the detailing.
A well-engineered product has a minimal cycle time, and can be produced with very little scrap.
Also in production small details can make a big difference.
High volume production
In High volume production small savings on the weight of the product and on the cycle time can add up to enormous savings. Optimizing a small technical product using FEM analysis can improve the function of the part and create great savings at the same time.
A pretty surface can be easily disturbed by inappropriate details on the inside. Even the way the plastic flows into the mold with every injection, has quite some influence.
When using metallic colors, this can become very apparent. Only with careful detailing, and with a well-chosen injection point, can unnecessary flow lines be avoided.
On the other hand, if required, flow lines can be used for the benefit of creating sections that can be broken away easily. (Additional openings, locking strips)