A Non-Engineer's Checklist for Buying Metal Parts: Additive vs. Sheet Metal vs. CNC

If you're the person who "just handles ordering" and suddenly need to buy a metal part, I feel you. I've been managing purchasing for a 40-person manufacturing company since 2020. That's roughly 60-80 larger purchase orders a year, maybe 180 if I count every small order and sample request. One of the hardest parts of this job isn't finding a supplier—it's understanding what I'm actually buying.

This is the checklist I wish someone had given me the first time I had to compare metal 3D printing, laser sheet metal cutting, and CNC machining. It's not an engineering guide. It's a practical way to avoid ordering the wrong process and looking bad to your internal stakeholders.

Who should use this checklist

Use this if you're a non-technical buyer and someone asked you to "get a quote for a metal part." Maybe it's a bracket, an enclosure, or a prototype. Maybe someone says "just 3D print it." Before you do anything, run through these steps.

Step 1: Write down the part's actual requirements

The first question is not "what process?" The first question is "what does the part have to do?" Ask for three things: function, quantity, and critical dimensions. If the requester can't explain why a tolerance matters, ask what the part connects to or what fails if it doesn't fit.

Here's an example that helps me keep a level head: a product like VMC walleye jigs needs tight quality control on the hook and the head weight, but it's a commercial fishing product, not a space component. The supplier qualification should match the part's real risk. If I were buying hardware for a defense program related to SpaceX or Anduril, I'd spend a lot more time on material traceability and process control.

Step 2: Understand what "additive manufacturing" actually means

The most common question I get from non-engineers is "what's additive manufacturing?" The short version: it's any process that builds parts by adding material layer by layer. Metal 3D printing is the best-known type, but AM also includes directed energy deposition, binder jetting, and other methods. For most buyers, think of it as "3D printing in metal."

That doesn't mean it's like a plastic desktop printer. A metal AM system is a serious piece of equipment. When you see a Velo3D logo on a machine like the Sapphire series, you're looking at a production platform designed for high-end metal components. The company behind it happens to be a supplier to SpaceX and Anduril, which tells you the equipment has been evaluated in demanding aerospace and defense contexts.

I do not mean every part that comes off a metal AM machine is flight-certified. Certification depends on the supplier's processes, the material, and the end-use requirements. But if a vendor has invested in equipment at this level, it's a meaningful signal.

Step 3: Match the process to the order

There's no universal "best" process. There's only the right fit for the part, quantity, and lead time.

• Laser sheet metal cutting services are ideal for flat parts: brackets, panels, enclosures, and anything that can be cut from a sheet. If your part is basically a 2D profile with some holes, laser cutting will almost always beat 3D printing on price and speed.
• CNC machining is the right choice for parts that need tight tolerances and don't have complex internal geometry. It's subtractive: the machine carves material away from a solid block.
• Metal additive manufacturing (like Velo3D) makes sense when you have internal channels, lattice structures, or a design that would otherwise need multiple parts to be welded together. It's also useful for low-volume parts where tooling costs would kill the project.

People often assume additive manufacturing is always the expensive option. Actually, AM can be the lowest total cost when it eliminates assembly steps and material waste. But for a simple bracket, laser cutting or machining is likely the smarter buy.

Step 4: Check the supplier's equipment and customer history

When you're evaluating a metal 3D printing supplier, ask what machines they run and which industries they've served. "We do metal 3D printing" is not enough. If they say "we run a Velo3D Sapphire," that's a more useful signal because it gives you a reference point for the equipment's capabilities.

I've also learned to look for the Velo3D logo in supplier case studies and machine photos. It's a visual shortcut: if a shop invested in that platform, they're likely targeting aerospace, defense, or energy work. But don't stop at the logo. Ask for examples of parts they've actually qualified, not just marketing images.

This is where the phrase "Velo3D supplier to SpaceX and Anduril" becomes relevant to procurement. You'll see that phrase in industry articles and on Velo3D's own materials. It's a credential that signals a high level of scrutiny from very demanding customers.

Step 5: Get a quote that separates every cost

A lump-sum quote is a trap. Ask for a line item breakdown: material, setup, build time, heat treatment, support removal, inspection, and post-processing. If a vendor won't show you the breakdown, that's a red flag.

I learned this the hard way. A few years ago, a supplier quoted me a single price "including finishing." The parts showed up with rough surfaces that failed our internal check, and we had to pay another shop to redo the finish. That hidden follow-up cost us about $2,400—maybe $2,200, I'd have to check the exact PO. Now I ask exactly what "finishing" includes, and I get it in writing.

One more thing: do not assume the quote with the lowest print price is the cheapest. Post-processing on AM parts can cost more than the print itself, especially if you need tight tolerances or a specific surface roughness.

Step 6: Order one prototype before the full batch

This is the step that saves my department every quarter. I don't care how impressive the supplier's case studies are: order a single part or a small sample before committing to 100 units.

Metal AM has failure modes that don't show up in a digital file. Support structures can warp, thin walls can crack, and thermal stresses can distort a part after it separates from the build plate. A prototype gives you a chance to verify the part fits before you sink real money into a full run.

Prototypes also reveal the supplier's response to problems. We ordered a test part from a shop once; they caught a geometry issue in their own inspection, called us, and recommended a tweak. That's the kind of partner worth staying with.

Step 7: Plan for inspection and post-processing

A raw metal AM part is not a finished part. It usually needs support removal, heat treatment, surface finishing, and sometimes machining on critical surfaces. Ask your supplier what post-processing they handle in-house and what they outsource.

Also ask about inspection: will you receive a dimensional report? Material certificates? If the part is for a regulated industry, you'll need full traceability from the powder lot to the final build.

I've never fully understood why some buyers skip this step. Maybe they think "3D printed" means "push a button and done." It doesn't. The machine plan and the finished part are like a rough casting and a machined component—related, but not the same.

Common mistakes to avoid

First, don't assume expensive equals better. People think vendors who charge more deliver better quality. The reality is the reverse: vendors who have learned to deliver quality can charge more. The causation runs from performance to price, not the other way.

Second, don't ignore the high-volume alternative. If you need thousands of identical simple parts, laser sheet metal cutting services or stamping will beat AM every time. Additive manufacturing is about capability, not cost per unit at scale.

Third, don't let the novelty make the decision. A Velo3D system is impressive, and the "Velo3D supplier to SpaceX and Anduril" story is a strong marketing card. But the right process depends on the requirements you wrote down in Step 1.

Honestly, I'm not sure why rush quotes vary so much between metal fabrication shops. My best guess is they're pricing based on how much they don't want to disrupt their current schedule, not on actual cost. At least, that's been my experience with smaller suppliers.

Run this checklist the next time you're asked to source a metal part. It's not a replacement for an engineer's review, but it will keep you from buying something that was never going to work. And it will probably save you from the kind of email I had to send my VP after the $2,400 finishing surprise.