The Cost, Weight, and Performance Case for Metal to Plastic Parts in OEM Programs

Metal-to-plastic conversion isn’t just a cost play — it’s an engineering decision that impacts performance, manufacturability, and supply chain agility. Beyond just material savings, plastics offer faster time-to-market, weight reduction, improved fuel efficiency and emissions, and significant performance gains. 

For OEMs, the shift to plastic parts has real benefits but requires the right partner to get it right. Design expertise is key, requiring deep materials knowledge and DFM experience. OEMs need partners who can collaborate across the value chain, aligning with cost, quality and performance goals. Let’s explore how partnering with Thogus can facilitate a successful metal to plastic parts transition. 

Why OEMs Are Replacing Metal with Plastics

OEMs are prioritizing weight reduction for easier handling, assembly, or performance improvement. Lighter parts can improve acceleration and system efficiency, and also enables faster and more precise manufacturing. 

When switching from metal to plastic parts, OEMs can expect lower material and processing costs compared to metal machining or casting. Engineering-grade plastics are often cheaper compared to metals like aluminum or steel, and injection molding allows for faster cycle times. 

In addition, injection molding allows for improved corrosion resistance and better chemical/environmental durability. Plastics do not rust, making them well-suited for outdoor applications without needed added coatings or treatments. They often require less maintenance over time, lowering total lifecycle costs and improving overall product reliability. 

Performance Factors Beyond Weight and Cost

Plastics can deliver comparable strength-to-weight ratios when properly engineered. They offer high strength with reduced mass, adding structural integrity in demanding applications. Injection-molded plastic parts can also achieve tight tolerances and repeatability, which is key for assemblies that demand precision. 

Advanced polymers can meet performance-critical demands. High-performance polymers like PEEK, PPS, and LCP can provide increased thermal resistance, making them well-suited for under-the-hood or industrial applications. Thermoplastics can also handle significant mechanical loads, and offer wear and friction resistance. 

Don’t underestimate the importance of matching resin properties to the specific application. Consider impact resistance, UV exposure, compliance standards and more in order to achieve success in metal-to-plastic conversion. 

Design for Manufacturability in Metal-to-Plastic Conversion

DFM is critical when moving from metal designs to plastic equivalents. Plastics behave differently, so simply copying a metal part’s design can lead to warping or unmanufacturable features. DFM reduces time, cost, and rework, and important design considerations include wall thickness, gating, draft, and part geometry.

At Thogus, we provide early engineering collaboration in order to prevent conversion pitfalls. Bringing in plastic part design experts during the early prototyping phase ensures that issues are caught before tooling, not after. We take a solution-first approach, engineering plastic parts that exceed metal part function rather than simply trying to replicate them.

How Tooling and Process Control Enable Reliability

Metal-to-plastic conversions demand precise tooling for dimensional accuracy. Plastics react differently than metals during molding, and require tooling designed specifically for plastics in order to maintain tight tolerances. Automation and monitoring help ensure consistency in high-volume runs. Since automated molding machines reduce variation and maintain consistent cycle times, OEMs can expect enhanced traceability and efficiency. 

At Thogus, we focus on precision tooling and process discipline. With our in-house tooling expertise, Thogus tailors molds to the chosen plastic resin and the part’s performance requirements, ensuring optimal results and maximizing reliability. 

Case in Point: Where Conversion Pays Off

Examples of successful metal-to-plastic conversations include industrial housings and enclosures that are converted from aluminum or steel, resulting in weight savings, faster assembly, and reduced corrosion risk. Consumer product components, such as power tool housings and electronics casings, have transitioned from metal to plastic parts for better design flexibility and lower production costs. Lightweight structural components used in automotive or aerospace equipment have also been converted to plastics that meet durability requirements, delivering weight reduction for better fuel efficiency and performance. 

OEMs choose plastics for scalability, supply resilience, and performance. Injection molding supports rapid, repeatable production at scale, enhancing design freedom, performance, and overall costs. 

Ready to Explore Metal-to-Plastic Conversion?

Conversion done right reduces cost, weight, and complexity without compromising performance. Partner with Thogus for engineering-led support in converting metal to plastic parts that meet your program’s performance and cost goals.