How designers across multiple industries are reducing costs and increasing profits by incorporating plastic instead of metal in new product designs.

Elk Grove Village, IL. 2/25/15  Ask any plastic manufacturer if a part should be designed in plastic or metal and they will give a list of reasons why plastic is always the way to go. Ask any metal manufacturer the same question and you will get a list of reasons why metal is superior. In our experience, as we talk with clients during their initial design phases, we have found there is a general lack of knowledge and many misconceptions surrounding the benefits of engineering-grade plastic resins.

Historically, metal has always been thought of as the go-to material when designing a part that needs to withstand the test of time. However, over the last sixty years there have been major advancements in the field of plastic engineering leading to new engineering-grade plastic resins that are continuously outperforming metal in industries across the board. Plastics now offer similar tensile strengths of metal, can be thermally conductive, resistant to heat and chemicals, and offer many other properties once thought of to be unique to metals. Certainly there will always be a need for metal, but for many industrial and consumer markets, plastic is becoming the material of choice for many convincing reasons, and the most important of which is cost reduction.

If a part is too expensive for the market, it will never sell, regardless of how amazing a new part design is or how much it will change the industry it is suited for. Companies are constantly dealing with tight margins and increasingly competitive marketplaces which puts an enormous amount of pressure on engineering teams trying to develop new products that are both cost-effective and of sound design. The automotive industry is a perfect example of this struggle – the federal government has established new standards requiring that by 2025 automotive brands must average 54.5 MPG throughout their consumer vehicle line-up for cars and light trucks; a daunting task for automotive designers who have to redesign their vehicles with materials that are cost effective, just as durable as their metal counterparts, but weigh significantly less. Just as the auto industry is dealing with reducing automotive weight and increasing efficiency, industries across the board are dealing with the issue of improving their part designs to outperform their competitors while reducing overall part costs.

Reducing overall part weight has a dramatic impact on a company’s bottom line through savings in shipping, packaging, and installation costs. Below is a specific gravity (kg/dm3) comparison of a few common metals compared to commonly used plastic resins:

MetalChart of plastic versus metal specific gravity

  • Aluminum: 2.5 - 2.8
  • Brass: 8.4 - 8.7
  • Copper: 8.8
  • Zinc: 6.9 - 7.2
  • Steel: 7.7


  • Polycarbonate: 1.2 - 1.4
  • Nylon (general grade): 1.2 - 1.7
  • Polyethylene: 0.92 - 0.95
  • Polypropylene: 0.90 - 1.04
  • ABS: 1.02 - 1.4
  • Acrylic: 1.15 - 1.2
  • Polyvinylchloride (PVC): 1.4


Although part weight reduction can be attributed to a large portion of cost savings for companies, plastic parts also generally cost less than their metal counterparts. Traditionally, plastic itself is often a less expensive raw material compared to metal. Additionally, the manufacturing process of plastic utilizes faster cycle times compared to metal, achieving lower production costs of plastic components versus metal components.

In addition to lower raw material and manufacturing costs, working with plastic allows product designers to incorporate multiple part components into a single mold or extrusion, reducing assembly costs and increasing the overall durability of the final product. Specifically within the lighting industry, we are seeing many manufacturers of luminaires converting their metal housing and heat sinks into single injection molded parts using modern engineering-grade polymers that have similar properties as aluminum. Below is a diagram released by PolyOne® Distribution highlighting the ability of being able to reduce the overall parts of a luminaire by converting to plastic.

Metal to plastic conversion

It is clear to see that converting from a traditional metal luminaire system to one composed mostly of plastic dramatically reduces the amount of assembly required to create the final product. Additionally, overall part weight is reduced and the manufacturing process becomes more efficient by going with plastic over metal with minimal secondary operations needed. This plastic conversion model that the lighting industry is moving forward with can easily be applied to many industries across the globe.

Plastic resins are continually evolving, becoming more suitable to accommodate modern product demands of being lightweight, durable, thermally conductive, and easy to manufacture. The engineering team here at Custom Plastics has decades of experience in assisting companies during the design phase of projects and are experts at letting our customers know what types of designs can and cannot work for plastic extrusion and injection molding. With the help of our engineering team, companies are often relieved that we are able to modify and adjust part designs to maximize efficiencies and reduce secondary tooling costs that often plague companies after the initial sample run is complete.

If you are starting a new project or are looking to convert a current product from metal to plastic, please don’t hesitate to give us a call at 847.439.6770 or email us at sales@customplasticsinc.com.


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