Compared to traditional metals, steel and aluminum, plastic resins are expensive and their high costs must be compensated for by a smart exploitation of their unique properties and the broad possibilities of processing. Often, customers are not willing to pay more than for a traditional device and, therefore when designing, it is essential to consider the [performance-to-cost] ratio rather than the cost itself. According to the context, an increase of the lifetime and the disposal after use can be taken into account if customers pay attention to those advantages and agree to pay a fair overspend. Of course, as for all industrial activities, it is necessary to reach a realistic balance between economic and technical parameters.
Generally, the potential [performance-to-cost] ratio of the used resin is the first examined parameter but one must keep in mind that it is only one element among others such as manufacturing costs and possibly running costs, disposal cost including waste collection and, if appropriate, recycling costs less recyclate value. The resin cost rating can be turned upside down by manufacturing costs on the one hand and by technical requirements on the other hand. For example unidirectional carbon fiber reinforced composites, despite their unique tensile strength rating, are not used for mass-produced cars because of the high cost of end parts.
There are many ways leading to higher [mechanical performance-to-cost] ratio. The most used is, perhaps, the thickness lowering thanks to more performing resins or reinforced compounds. Apart from the direct weight and cost savings there are also cooling and cycle time savings, which reduce processing costs. However, strength is reduced in proportion of the affected dimensions.
Randomly dispersed short glass fibers reinforced polymers are often used but can induce some anisotropy, which can be minimized by partly replacing some glass fibers by glass beads.
For some applications, construction for example, a high [durability/cost] ratio leads...