Machining is all about precision, strength, and durability, but the material you choose can make or break your production process. Some materials cut like butter, while others eat through tools, heat up, or deform under stress. Whether you’re making aerospace parts, medical devices, or industrial components, picking the right metal or plastic affects speed, cost, and final performance.
Let’s break down the best materials for machining—and which ones to avoid unless absolutely necessary.
Metals: Strength, Cost, and Workability
Aluminum: The Easy-to-Machine All-Star
Aluminum is lightweight, corrosion-resistant, and cuts fast, making it a top choice for aerospace, automotive, and industrial parts. 6061 aluminum is the most common, offering good strength and affordability, while 7075 aluminum is tougher but harder to machine. It’s one of the most cost-effective and tool-friendly metals out there.
Stainless Steel: Tough, But Hard on Tools
Stainless steel is the go-to for medical, marine, and food-grade applications, thanks to its corrosion resistance and strength. 303 stainless steel machines the easiest, while 316 stainless steel offers superior corrosion resistance but requires slower speeds and tougher tooling.
Carbon Steel: Strong and Budget-Friendly
Carbon steel is durable, affordable, and easy to machine, making it a great option for shafts, gears, and structural parts. 1018 carbon steel is highly machinable, while 1045 carbon steel is stronger but tougher to cut. It rusts easily, so it often needs protective coatings.
Titanium: The Strength Champion (and Tool Killer)
Titanium is lighter than steel and just as strong, making it essential for aerospace and medical implants. But machining it? Painfully slow and tool-intensive. Grade 5 titanium (Ti-6Al-4V) is the most common, offering high strength but requiring specialized tooling and low speeds. It’s expensive and difficult to machine, so only use it when absolutely necessary.
Plastics: Lightweight, Tough, and Sometimes Tricky
Delrin (Acetal): The Machinist’s Favorite Plastic
Delrin is strong, wear-resistant, and holds tight tolerances, making it perfect for gears, bushings, and mechanical parts. It machines cleanly without melting, unlike some softer plastics.
Nylon: Tough, But Prone to Moisture Issues
Nylon is impact-resistant and self-lubricating, great for bushings and gears, but absorbs moisture, which can affect stability over time. It also generates heat when cut, so proper cooling is key.
PTFE (Teflon®): The Slippery, Chemically-Resistant Workhorse
PTFE is heat-resistant and chemically inert, making it ideal for seals, gaskets, and medical components. But it’s soft and deforms easily, making tight tolerances tricky.
PEEK: The High-Performance Powerhouse
PEEK is one of the strongest, most heat-resistant plastics, used in aerospace, medical, and automotive applications. But it’s abrasive on cutting tools and extremely expensive, so it’s only used when nothing else will do.
Making the Right Choice
Material selection impacts cost, machining time, and durability. Aluminum is fast and affordable, stainless steel offers strength and corrosion resistance, and titanium is only for extreme applications. For plastics, Delrin is the easiest to machine, while PEEK and PTFE require extra care and cost considerations.
At RapidMade, we specialize in precision machining and can help you choose the best material for your needs. For expert consultation, visit rapidmade.com or contact info@rapidmade.com.
