Tell us what your part does and where it is used. The finder checks every material against your needs, shows why each one wins or drops out, and turns your answers into a spec you can send with your drawing.
Ratings are a quick guide for comparing materials, not a material spec sheet. Our engineers confirm the material and grade in your quote. Full property data (density, strength, hardness) is in the CNC machining materials guide →
The fastest way to find a CNC material by requirement is to start with the one need that rules out the most options. Food contact points to stainless steel 304 or 316, salt water to 316 or titanium, heat above about 120°C rules out most plastics except PEEK and PTFE, and electrical insulation rules out all bare metals. Tap Use in finder on a card to add that need.
Stainless steel 304 and 316 are almost non-magnetic when annealed, but 304 can turn slightly magnetic after machining or bending. Stainless 416, 17-4 PH and carbon steel are magnetic.
Stainless steel and titanium keep their strength far above 300°C, while aluminum starts to weaken above about 150°C. In plastics, PEEK and PTFE work continuously up to about 250–260°C; POM, ABS, nylon and PC soften around 80–115°C.
Stainless steel 304 and 316 are the default food-contact metals. Anodized aluminum and FDA-grade POM, PTFE and PEEK are also used. A part is food safe only with the right grade, a suitable finish and a test report for your market.
For salt water and sea air, titanium and 316 stainless steel are the most corrosion-resistant common metals. Bronze is a classic marine metal. Aluminum needs anodizing, and bare mild steel rusts quickly.
Titanium Grade 5 (about 950 MPa at 4.43 g/cm³) has the best strength for its weight. Aluminum 7075-T6 (about 570 MPa at 2.81 g/cm³) is the lower-cost option. PEEK is the strongest light plastic.
Copper conducts electricity best of the common CNC metals, then aluminum, then brass and bronze. Stainless steel and titanium conduct poorly, and all plastics are insulators.
All six plastics in this guide (POM, ABS, nylon, PC, PEEK, PTFE) insulate electricity, and PEEK and PTFE also handle heat. Anodizing on aluminum is thin and not a reliable insulator.
Aluminum 6061 moves heat well (about 167 W/m·K) at low cost and weight. Copper is about twice as good but heavier and pricier. Stainless steel is poor (about 16 W/m·K).
PTFE has the lowest friction of any common plastic; POM (Delrin) is slippery and holds tight sizes; nylon is tough. Bronze is the usual metal for bushings.
Steam sterilization (autoclaving) runs at about 121–134°C. Stainless steel 304 and 316, titanium, PEEK and PTFE handle repeated cycles; ABS, POM and nylon do not.
PTFE is not affected by sunlight. Most other plastics, such as ABS, POM and PC, need a UV-stable or black grade outdoors. Metals are not harmed by UV light.
Polycarbonate (PC) is the usual clear, tough plastic: it is very hard to break and can be polished after machining, but it scratches easily.
Source: Typical values; source: ASM Handbook / MatWeb and resin makers’ data sheets for plastic heat limits; actual values depend on grade, temper and supplier certificate. Full data: typical properties table.
To choose a CNC material, write down the part’s job, where it is used and its top three needs, then check rules such as FDA food contact or RoHS, and finally match the finish and quantity. Start with aluminum 6061; move to stainless steel only for food, water or chemicals, to engineering plastics to slide or insulate, and to titanium or PEEK only if nothing cheaper passes.
The part’s job (cover, shaft, gear, heat sink) often cuts the material list in half, because a shaft needs strength and a cover needs low cost.
Food, water, salt, sunlight, cleaners and heat cause most material failures, so note each one and the highest working temperature of the part.
No material is best at everything: rank low cost, light weight, strength, wear, looks or conductivity and keep only the top three.
Food contact (US FDA 21 CFR, EU 1935/2004), RoHS and medical rules remove some materials completely, so check them before you compare prices.
The finish you want (anodizing, polishing, powder coating) narrows the metal, and for orders above about 500 pieces the fastest-machining material usually costs least.
The Dayao Material Finder is a free first filter, not a final specification: it scores 18 common CNC metals and plastics on your answers to 7 questions and rules out any material that clearly fails, such as a plastic above its heat limit. An engineer then confirms the exact grade against your drawing when you request a quote.
Reviewed by the Dayao engineering team · Updated October 2026
Full data for all 18 materials lives in the Dayao CNC machining materials guide: typical density, tensile strength and hardness, 14 A-vs-B answers such as 304 vs 316, the 9 most common material problems, food-contact rules and which finish fits which metal. Use the finder for a shortlist and the guide to check the details.
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