You’ve heard the saying, “They don’t make things like they used to.” Or how about the one of new products just aren’t made to last very long anymore? In some cases that may be true, and others it could be that the wrong material was chosen. If you want durability and practicality, perhaps now is the moment to switch over to plastic parts instead of metal. If you’re unsure on making the switch, you should read below on why plastic may be the better choice for your new project.
Is Plastic or Metal the Better Choice?
Metal products have been used for centuries. Helmets in Roman times, cutlery in the Wild West, and metal is still used today in many instances. Debating if it’s the better choice isn’t cut and dry. There are many instances where metal is the better choice on a new project. Determining that is where the research needs to be done in-depth, and two factors that should be considered are durability and practicality.
Durability is defined as the ability to withstand wear, pressure, or damage for an extended period of time. There are thousands of resins available, and many engineered resins can exhibit equal or increased strength when directly compared to metal. For instance, thermoplastic composites have been proven to be as strong and durable as steel or aluminum with the added bonus of reduced weight. Three categories of reinforced plastics offer the most competition to metals:
- Short Glass Fiber-Reinforced Plastic – increased strength and stiffness, with a high heat tolerance
- Long Glass Fiber-Reinforced Plastic – high-performance with additional weight reduction
- Carbon Fiber-Reinforced Plastic – additional weight reduction and perfect for large components or panels
Beyond strength, plastics can offer increased durability through natural corrosion resistance. Metals typically require a secondary or tertiary operation to apply a coating to prevent corrosion. That may include a spray or dipping process to apply that specific coating. Specialized metal alloys offer significant corrosion resistance, but that can also require extra expense on the investment side as a penalty. Plastic resin is naturally resistant to corrosion and should not need the extra steps to prevent corrosion from a harsh environment.
Practicality is a harder concept to define. It involves the subject being used in action in a sensible manner. Does that equate to lower costs or reducing the volatility of the raw material? Can that also have reduced restrictions incorporated as well? What some may think is a bad idea, others may think it easily fits into a sensible situation.
Plastic injection molding can offer reduced tooling costs compared to metal forming or casting dies. Casting dies can take up to 16 weeks to complete. Injection molding dies can be completed in as little as 6 weeks. For practicality you could be trialing your new injection molding dies and producing parts in half the time of casting dies. Plastic injection molds can also last up to six times as long as a casting mold before requiring replacement. That increased durability and wear resistance can save additional money over the life-cycle of the product.
Beyond lower tooling costs, plastic injection molding can offer lower manufacturing costs as well. Injection molding typically produces less scrap material from manufacturing, doesn’t require extra lubricants for forming, nor do they require significant secondary work before shipping to a distribution center or directly to a customer. Companies that have made a change from metal to plastic have identified cost savings of up to 50% through individual part cost and an increase in manufacturing efficiency.
Industries Already Converting Metal Parts to Plastic
Many industries are currently converting from metal parts to plastic through replacement tooling and new product development. Here are some of the latest ideas coming to market:
- Logistics and Supply Chain: Packaging is being converted from disposable materials to reusable plastic. Shipments on cargo ships encounter corrosive sea water that doesn’t affect a plastic container. Individual parts and bulk packaging are also not affected, which makes the plastic packaging indefinitely reusable.
- Automotive: The automotive market has seen major body panels made from engineered resins. Niche markets and low volume production are benefitting from plastic with the aftermarket able to 3D print large parts on a practical scale. Replacement and new products may be developed with plastic in mind to reduce cost and weight.
- Home Appliances: The home appliance market has seen more and more appliances, both large and small, converted to engineered plastics. Individual components can be made more efficiently with plastic injection molding. Exterior appliance body panels could be designed for plastic to reduce weight and secondary coatings. Any product can have multiple color options with the simple change of the resin coloring. A similar option for metal may not be available in a practical manner.
- Aerospace:With plastic injection molded products weighing less than metal, many metal options are being replaced with engineered plastics. Small changes can add up, and that can reduce the overall weight of the airplane. Cabin interiors, insulating components, fasteners, gears, and more are slowing converting to plastics to offer more competition to metals.
Durability and practicality are often debated when the choice to convert metal to plastic seems to be very enticing. Deciding which material is better may not be an easy choice to make. You may need a partner well versed in the process. SEA-LECT Plastics can aid with resin selection, turn-key assembly options, and program management to see the complete development cycle through with success. Give us a call at (425) 339-0288 or email us at mattp@sealectplastics.mystagingwebsite.com. We can offer you advice on the best technology to use, the best materials to meet your product demands, and how to navigate through each development stage. At SEA-LECT Plastics, we specialize in military product applications, outdoor adventure gear, musical instruments, supporting the medical and consumer product industries. Our goal is to make your project efficient and cost-effective to manufacture, assemble, and ship no matter how complicated your concept is.
Matthias Poischbeg was born and raised in Hamburg, Germany. Matt moved to Everett, Wash., after finishing his bachelor’s degree in business in 1995 to work for Sea-Dog Corporation, a manufacturer, and distributor of marine and rigging hardware established in 1923.
In 1999, Matt took over the reins at Sea-Lect Plastics Corporation, a sister company of Sea-Dog and a manufacturer of plastic injection molded products with an in-house tool & die shop. Matthias Poischbeg is also a contributor to Grit Daily.