Is plastic an ideal replacement for metal?
28 February 2016
RP Technologies turned to partner, EMS Grivory for its knowledge to ensure metal replacement plastics match customers’ specifications.
products are targeting metal replacement from the concept idea to the sustainable transformation into injection moulding. In the Automotive Industry the drivers behind metal replacement are the reduction of component cost and component weight, which can be achieved by intelligent integration of functions and also as a result of no post treatment processing.
But the question we often hear around metal replacement in the modern day vehicle is: can plastic really replace metal? And is it possible to prove this before committing to production tooling?
It is clear that metals
have strong solid properties; however, with impressive design techniques, high performance polymers
are now challenging metals
. And by using sophisticated FEA and MF software
component predictability is improving.
There is a strong trend towards virtual component development and testing, which makes it possible to greatly shorten development times while achieving better component quality. However, consideration has to be given at the start of a project for the prototype phase of introducing polyamides for metal replacement.
Grivory HT Polyphthalamides (PPA) need to be processed correctly to ensure all the characteristics of the material are optimised. Incorporating this at the prototyping
stage by utilising aluminium tooling involves less risk as it’s a cheaper and faster process to produce prototype components for testing.
One of RP Technologies’ specialities is processing high temperature metal replacement materials
such as Polyphthalamides (PPA) whilst using aluminium prototype tooling. The company's extensive experience in this field gives customers high quality, reliable prototype components.
When processing PPAs there are many different factors that have to be taken into consideration from a tooling point of view. The grade of aluminium used, how the temperature is controlled, how the material is conditioned and the type of lubricant used on the tool to overcome extremes of temperature (140°C - 180°C) have to be given serious consideration to ensure components are produced within the correct process conditions of the Polyphthalamides.
If all of these conditions are correct, then a robustly designed part will have the structural integrity of the material that gives the moulded component its optimum condition. This results in prototype parts of production quality that not only withstand full testing and development, but also meet critical tight tolerances.
Grivory PPAs are characterised by their high-performance properties. Technical injection moulded parts made from Grivory HT retain their shape even at high operating temperatures. Characteristics such as stiffness and strength - among the most important in metal replacement - are achieved thanks to little change in property values after absorption of water. In addition, low warpage, good dimensional stability, chemical resistance and a high surface quality are all possible.
A good application example of Grivory polyamides is their use in a new generation of automotive adaptive headlights - so-called AFL (Adaptive Forward Lighting
AFL uses moveable lenses to enable the light to be dynamically adjusted to suit the road. The required manoeuvrability in the headlight unit, which weighs about 0.4kg, is provided by a swivelling module made of Grivory HT1. This component is exposed to temperatures of up to 150°C for long periods.
To guarantee precise angling of the light cone, the swivelling module must not become deformed, nor must any vibrations impair the functioning of the lighting
system. Grivory HT1, with its extremely high rigidity, durability and heat resistance, offers the required level of performance for this demanding application where tight dimensional tolerances must be met.
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