Depending on your application, sometimes metals will be appropriate for your design and sometimes plastics.  Modern thermoplastics have made great strides in replicating many of the strengths of metals without their drawbacks.

For example, many thermoplastics offer strength, rigidity and impact resistance that meet or exceed many metals, without the added weight.  Many transportation applications have changed from metals to plastics for this reason alone. 

Another misconception about plastics is that they burn where metals don't.  Although this is true of many plastics, there are flame retardant packages that can be added to thermoplastics that make them adhere to often stringent flame-smoke-toxicity requirements of modern aircraft and land vehicles such as rail cars.  Many thermoplastics on their own, such as PEEK and Ultem, also offer high melt points, over 575 degrees F.  Combined with glass, carbon or Aramid reinforcements, structural integrity can be maintained while achieving static dissipation.

Metals are naturally conductive without fillers, and generally are stronger and stiffer than even reinforced plastics.  It usually costs less for tooling as well.  Drawbacks can include higher weight, melt points that can be lower than some thermoplastics, and corrosion.

Depending on your application, metal or thermoplastic can solve your design challenge.  Let Certified's engineers discuss with you your specific project.  Although we do not work with metals, we can advise whether or not plastic extrusion is the correct solution.  If not, we'll tell you!