Materials
CNC Material Selection
Match the material to the job, not the other way around.
To choose a CNC material, start from your part’s actual requirements, not habit: rank strength, weight, operating temperature, corrosion environment, wear, electrical or thermal needs, appearance, and cost, then pick the cheapest material that clears all of them. For most parts that’s 6061 aluminum; you only step off it when a specific requirement forces the move. The materials hub covers every grade in detail, and a real person consults on the call before you commit. Send a file for a quote in 24-48 hours.
Updated October 2026
Aluminum 6061
The default alloy for a reason: strong enough for most work, light, and it anodizes well.
Material selection starts from requirements, not habit
The most expensive material mistakes happen when someone picks a grade out of habit instead of need. Before you look at any alloy, list what the part actually has to survive and rank it. Strength and load: will it carry real force, or just hold a sensor in place? Weight: does every gram matter, or is it bolted to a frame? Operating temperature: room temp, or 200F next to a motor? Corrosion environment: indoors and dry, washed down, or living in saltwater? Wear and hardness, electrical or thermal conductivity, cosmetic appearance, and cost round out the list.
Almost no part needs all of these at once. The skill is figuring out which two or three genuinely decide the choice and which are nice-to-haves. Once you’ve ranked them, the material usually picks itself: choose the cheapest grade that clears every hard requirement, and stop there. Over-speccing is just paying for properties the part never uses.
Aluminum: the default for most parts
If you have no strong reason to use something else, the answer is aluminum. It’s light, corrosion-resistant enough to live bare indoors, it anodizes cleanly in clear, black, or color, and it cuts fast and predictably. Since machining time is the dominant cost in a custom part, that speed is what keeps aluminum CNC parts affordable. 6061 is the workhorse, roughly 40 ksi yield in the T6 temper, weldable, and stocked in every shape; it covers most brackets, housings, plates, and manifolds.
Step up to 7075 when strength is the deciding factor: about 80% higher yield, the alloy of high-load brackets and motorsport hardware, at two to three times the material cost and no weldability. One catch worth knowing: 6061 and 7075 are equally stiff, so neither fixes a part that flexes too much (that’s geometry, not grade). When the call is close, the 6061 vs 7075 comparison walks through it, and both can be quoted on one request.
When metal needs to be more than aluminum
Corrosion or strength sometimes pushes you past aluminum, and that’s where stainless and steel come in. 303/304 stainless is the general-purpose corrosion grade: 303 machines easily, 304 welds and resists more chemicals, and both handle washdown, food, and outdoor use. When you need real strength and corrosion resistance together, 17-4 PH is the heat-treatable answer for shafts, valve parts, and load-bearing hardware that can’t rust. The full grade rundown lives on the stainless grades page.
If corrosion isn’t the concern, steel gives you the most strength per dollar: alloy and tool steels for shafts, gears, dies, and high-load fixtures, usually with a plating or coating to keep rust off. Titanium earns its place when you need the best strength-to-weight or biocompatibility (aerospace, medical implants, premium hardware), accepting a real price premium and slower, more deliberate cutting. Don’t reach for titanium where 304 already works; the price gap is large and rarely justified.
Brass and engineering plastics
Brass machines beautifully, conducts electricity well, and looks the part, which makes it the pick for electrical contacts and terminals, fittings, fluid components, and anything decorative. It’s denser and pricier than aluminum, so use it for what it does best rather than as a default.
Plastics solve problems metal can’t. Delrin / acetal is the low-friction, dimensionally stable choice for gears, bushings, wear pads, and snug-fitting mechanical parts where you want quiet, self-lubricating motion and electrical insulation. PEEK is the high-performance plastic: it holds up to high temperature and aggressive chemicals where Delrin would soften or swell, which is why it shows up in medical, semiconductor, and chemical-handling parts. Both cut cleanly and avoid the cost of metal where the application allows it.
Decision tips and getting it priced
A few rules keep the choice honest. Default to 6061 unless a ranked requirement pushes you off it. Don’t over-spec: titanium where 304 works, or 7075 where 6061 carries the load, just spends money the part doesn’t need. And remember cost scales two ways, the raw material price and how hard the grade is to cut, so a cheap-per-pound material that machines slowly can still quote high. Naming your real loads, environment, and finish on the request lets the price land where it should. Grade is only half of it: the geometry you draw moves the number just as much, which is what design choices that raise a quote covers.
If you’re between grades, that’s normal, and you don’t have to decide alone. A real person reviews your files and consults on the grade before you commit; it’s part of the quote, not an upsell. Note your requirements (or just your uncertainty) and you’ll get a recommendation back with the price. When the call is close, ask for the part in one grade or a couple to compare side by side, then start a quote and a real number comes back in 24-48 hours.
Questions
Before you send a job.
01 How do I choose the right CNC material?
Rank what the part actually needs, strength, weight, temperature, corrosion, wear, conductivity, appearance, and cost, then pick the cheapest grade that clears every hard requirement. For most parts that’s 6061 aluminum. You only move off it when a specific need (more strength, corrosion resistance, heat tolerance, or low weight) forces the change. The materials hub details each option.
02 What’s the best default material if I’m not sure?
6061 aluminum. It’s light, corrosion-resistant indoors, anodizes well, cuts fast (which keeps the price down), and is stocked everywhere, so it covers the bulk of brackets, housings, and plates. Step up to 7075 only when a part bends or cracks in 6061, and switch materials entirely only for heat, corrosion, or weight reasons aluminum can’t meet.
03 When should I choose stainless over aluminum?
When corrosion resistance or strength is the deciding factor. 303/304 stainless handles washdown, food, marine, and outdoor exposure that bare aluminum can’t; 17-4 PH adds heat-treatable strength on top of corrosion resistance. The tradeoff is cost and slower cutting, so use stainless where the environment or load genuinely calls for it, not by default.
04 Is titanium worth the cost?
Only when you truly need its strengths: the best strength-to-weight ratio or biocompatibility for medical and aerospace work. Titanium carries a real price premium and cuts slowly, both of which raise the quote. If 304 stainless or 7075 aluminum meets your requirements, use them instead, titanium where a cheaper grade works is wasted money.
05 Can someone help me pick a material before I order?
Yes. A real person reviews your files and consults on grade as part of the quote, not as an upsell. Note your loads, environment, and finish (or just say you’re unsure) and you’ll get a recommendation back with the price. When the call is close, you can quote the part in one grade or a couple to compare before committing.
Get Started
Send us your files.
We’ll take it from there.
A quote in 24-48 hours, no minimums. Like the quote, and we’ll make your parts and ship them to you.
Get a Quote