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Plastic vs Metal – is cost the only consideration?

June 23, 2016

PLASTIC vs Metal – is cost the only consideration?

There will always be an argument for using metal over plastic, which has often been seen by both the engineering fraternity and the general public as a ‘poor cousin’.  However, the field of Plastic Component Design and Production has been evolving in recent years, and should now be viewed as a technical solution that in some cases can out-perform machined or cast metal ……

As is often the case, the automotive and aerospace industries have been leading the way. The cabin of even a prestige car now contains a vast array of technical plastic solutions.  Plated plastic bezels and door handles look like chromed steel or brushed aluminium, but the strength of the technical polymers used keeps dimensions the same, whilst greatly reducing component weight. Reduced weight is critical if vehicles are to meet the political and economic demand for better fuel economy and lower emission levels.

In more recent years, under bonnet components are also becoming more common. No longer just water reservoirs filter housings and fans, these days even engine manifolds can be produced using special heat resistant plastics.

Injection moulded parts can also be complex and of a tight tolerance, for example having clips that negate the need for metal fixing (which helps with build time and re-cycling legislation).

So what about developing new products in plastic, or replacing heavy and/or expensive metal parts?

As a starting point, the UK has a good number of specialised technical polymer suppliers like Counterplas that can provide a specially ‘compounded’ solution.  There is a vast array of polymer types available, each with their own inherent properties. On top of this, fillers can be added that alter the strength and stiffness of the plastic.  Additives can also be built into the plastic, from anti-microbial agents, colour pigments, flame retardants, fluorescent additives, and even anti-counter fitting agents!  In conclusion, there is a plastic grade available that is capable of taking the place of a metal in most engineering applications.

What about part design and production?

The UK Plastics Sector is now doing well.  There are plenty of highly competent Design and Development companies that know everything about designing a functional plastic component that can be manufactured with the minimal amount of tooling outlay. If you have a design already, Counterplas can produce 3D Printed components, or low cost aluminium tooling directly from a CAD file. Fully hardened production tooling is also an option.

Do you need more information? Contact our sales and technical team, they are always happy to help.