Is It Cheaper to 3D Print or CNC Machine a Single Part?

What Drives CNC Cost

A CNC machine cuts a part out of a solid block. Much of the cost is spent before the first chip falls, and that cost is the same whether you order one part or fifty.

• Setup: loading stock, setting work offsets, and proving out the first part.
• Programming: a machinist builds toolpaths in CAM software for every feature.
• Fixturing: odd shapes need soft jaws or custom fixtures to hold them, sometimes for several setups.
• Material removal: machine time grows with how much material must be cut away, and the stock you pay for is often much larger than the finished part.
• Tool changes: small radii, deep pockets, and threads each add tools and time.
• Minimum charges: many shops have a minimum per order to cover the fixed work above.

Spread across many parts, those fixed costs become small. On a single part, they are most of the price.

What Drives 3D Printing Cost

FDM printing builds the part layer by layer straight from your file. There is no tooling, no fixture, and very little programming, so cost tracks the part itself.

• Material volume: the plastic in the walls and infill, which is usually far less than a machined block.
• Print time: larger and taller parts take longer on the machine.
• Supports: overhangs need support material that adds time and removal work.
• Finishing: support removal, cleanup, inserts, or any secondary work.

Because complexity costs almost nothing extra to print, a part with internal channels or organic curves can cost about the same as a simple block of the same size. For a closer look at pricing factors, see how much 3D printing costs in Houston.

When 3D Printing Is Cheaper

• One part up to a few hundred plastic parts, where CNC setup cannot be spread out.
• Internal features such as channels, pockets, and hollow sections that a cutter cannot reach.
• Complex or organic shapes that would need many setups or five axis machining.
• Fast design changes: edit the file and print the next revision with no new fixture or program.
• Bridge production while injection molds or machined versions are still being made.

When CNC Machining Is Cheaper

• Metal parts. FDM prints plastics and composites, so aluminum or steel parts belong on a machine.
• Tight tolerances beyond what a printed feature can hold.
• Parts that need high strength in every direction. Machined stock is uniform, while printed parts are weaker between layers.
• Simple geometry at volume, such as plates, spacers, and blocks, where setup is quick and cutting is fast.
• Critical sealing faces that need a machined surface finish.

If your part has a tolerance callout that matters, check it against our FDM tolerance guidance before you decide.

A Combined Approach

The cheapest answer is sometimes both. A few ways shops combine the two processes:

• Print most of the part, then machine one critical face, bore, or thread.
• Print the fixtures, jigs, and soft jaws that hold a machined part, cutting setup cost.
• Print early prototypes to settle the design, then machine the final metal version.

How to Decide for Your Part

Run through this checklist before you request quotes:

• ✓Material: does it have to be metal, or will an engineering plastic do the job?
• ✓Tolerance: which features truly need tight tolerances, and which do not?
• ✓Quantity: one part, a short run, or ongoing production?
• ✓Geometry: are there internal features, undercuts, or complex curves?
• ✓Timeline: how soon do you need parts, and will the design change again?

How Spline Arc Can Help

We print FDM parts in house on our Houston print farm, and we source CNC machining through our vetted partner network, managed by Spline Arc as your single point of contact. Send us your file and we can quote both options so you can compare them side by side. Orders start at $150. For recurring business orders, see our industrial 3D printing services, or request a quote.

Frequently Asked Questions