How to Prepare an STL File for 3D Printing (No File? Send a Photo)

A clean file is the difference between a print that comes out right the first time and one that fails halfway up the plate. The good news: preparing a file is mostly about avoiding a few common mistakes. And if you don't have a file at all, that's fine too. Here is everything you need to know to hand us something we can print.

File types we accept

You don't need to convert anything to a specific format before sending it. We work with all the common ones.

If you have a choice, STEP is ideal for mechanical parts because it carries true dimensions and clean surfaces. STL is perfectly fine and the most common thing we receive. Send what you have.

Common pitfalls to avoid

Most file problems fall into a short list. A quick check before you send saves everyone time.

• Wrong scale or units. STL files don't store units, so a part can show up at 10 times its intended size, or one tenth. Always tell us the intended dimensions of at least one feature.
• Non-manifold geometry. Holes in the mesh, flipped faces, or surfaces that don't fully enclose a solid. The model needs to be "watertight" to print.
• Walls too thin. Anything below roughly 1 mm gets fragile and may not print reliably. For structural parts, thicker is better.
• Tiny unsupported details. Fine features can be lost or break off, especially on FDM. We'll flag these.
• Overhangs without support. Steep overhangs need support material. We handle that in setup, but extreme geometry may need a redesign.
• Merged or overlapping bodies that confuse the slicer.

You don't have to fix all of this yourself. Part of what we do is review the file and catch these before printing. But knowing them helps you send a better file.

Design-for-print tips

If you're modeling the part yourself, a few habits make for stronger, cleaner prints:

1. Mind wall thickness. Keep walls at or above 1 to 2 mm for durability; more for load-bearing parts.
2. Add fillets to corners. Rounded internal corners reduce stress concentration and cracking.
3. Design for orientation. Layer lines are weakest in the direction they stack, so plan for the part to be printed with load running along layers, not across them.
4. Avoid extreme overhangs where you can; angles under about 45 degrees from vertical usually print without support.
5. Build in tolerance for fits. For parts that slot together, leave a small gap (often 0.2 to 0.4 mm) so they actually assemble.
6. Keep holes a touch oversized. Printed holes tend to come out slightly undersized; account for it or plan to ream them.

If any of that sounds like a foreign language, don't worry. Tell us what the part needs to do and we'll handle the print-specific decisions.

No file? Send a photo

Here's the part people don't expect: you don't need a 3D file to get a 3D printed part. A large share of our work starts with no model at all.

If you don't have a file, you can send us:

• The physical part itself (the broken original is the best reference there is).
• Clear photos from multiple angles with a ruler, coin, or calipers in the shot for scale.
• A rough sketch with dimensions for something that doesn't exist yet.
• A reference product you'd like us to adapt or improve.

From any of those, we can model the part for you. A photo with a known measurement is often all it takes to get a quote started.

A quick pre-send checklist

Before you hit upload, run through this:

• Is the scale correct, or have you noted the intended size?
• Is the model a single watertight solid (or clearly separated parts)?
• Have you noted the intended use so we pick the right material?
• Any critical dimensions that must be exact?
• A deadline we should know about?

Send it over

When you're ready, upload your file (STL, STEP, 3MF, OBJ, or a ZIP of several) and we'll review it for printability, usually within a business day. No file? Request a quote with a few photos and we'll take it from there, built layer by layer in Texas.