Over the past century, the plastics industry has saturated our world and drastically changed the way we live. Today there are high-strength polymers that can meet and even exceed metals in terms of strength and flexibility. This has had a transformative effect on parts manufacturing, allowing metal parts to be swapped out for plastic parts that provide the same structure, but with reduced weight, more design flexibility, more efficiency, and less cost. If you want to take advantage of these changes with an existing part, it’s time to look at a metal-to-plastic conversion for the component.
The Advantages of Converting to Plastic
When it comes to converting a metal part into a plastic part, there are quite a few advantages to be had. When doing a cost-benefit analysis (see below), remember these advantages, but also balance them against the considerations of converting.
- Weight: Plastics are significantly lighter than machined or cast parts, especially when compared to dense metals like iron.
- Cost: Plastics are cheaper to use than metals, especially when it comes to heavily machined components.
- Corrosion: Unlike metals, corrosion isn’t a factor, especially important for medical and food-safe parts.
- Design: With molded plastics, you have more design freedom than with machined metal. Steps in metal parts that would require additional machining (and time and money) are removed from plastic parts.
- Multi-Material: The ability to fuse several plastics together in a single part through overmolding, such as creating a soft seal with a rigid center.
- Throughput: Plastic parts also have a faster production cycle than metal parts. Something to keep in mind especially if you’re expanding production.
Doing a Conversion Cost-Benefit Analysis
While there are a lot of perks for a metal-to-plastic conversion, it’s important to understand there are several costs and tradeoffs that need to be considered. Likewise, if you’re only interested in one feature from the above list (i.e., saving money), you may need to rethink your strategy. Some things to keep in mind during this analysis.
The mold used to produce the parts is a complex part of machinery in its own right. It’s important to factor in the cost of this mold’s creation as part of the unit price per part.
What do you need this plastic to do? What qualities (such as tensile strength) do you need in this plastic? Does this plastic need to be medical-grade or food safe? How much are you willing to spend on the plastic? Can you use reusable plastics for scrap reduction vs. machining metal?
What production schedule are you looking at? Analyze how many parts you need per month or per year. The higher this is, the cheaper per-unit plastic parts become. Make sure to balance all these factors when thinking about how producing in plastic will affect quality, product life, and the function of the end device.
Want to learn more about metal-to-plastic conversions and if the process is right for you? Contact Midstate Mold. With over 50 years in the injection molding business, including in-house mold design and manufacturing, we can provide you with all the tools to help decide if metal-to-plastic conversion is right for your part.