Before you can get a fast quote or a clean part, you need to prepare a 3D model for printing the right way. After 22+ years of running prints for engineers, inventors, and designers across Los Angeles, we can tell you that most failed prints and delayed quotes trace back to the same handful of file issues. Here is what we check on every incoming file at our Glendale studio, and how you can catch these problems before you hit send.

Start With the Right File Format

For most jobs, STL remains the standard. It describes your part as a mesh of triangles and works with every technology we run, from FDM and SLA to SLS, MJF, PolyJet, and DMLS metal printing. When you export an STL, keep the resolution sensible: too coarse and curved surfaces show visible facets, too fine and the file balloons past 100 MB with no visible benefit. A chord height of about 0.01 mm is plenty for most parts.

If your part may need design changes, send a STEP file as well. STEP preserves the true CAD geometry, so we can adjust dimensions, add draft, or thicken walls without rebuilding the model. 3MF is also welcome, since it carries units and color data that STL does not. OBJ works for full-color models with textures.

Get Wall Thickness Right for Your Process

Wall thickness is the most common reason a model that looks perfect on screen fails on the printer. Each technology has its own practical minimum. As a rule of thumb, keep walls at 1 mm or thicker for FDM, around 0.5 to 0.8 mm for SLA and PolyJet, and about 0.7 to 1 mm for SLS and MJF. Metal printing generally wants 0.5 mm minimum, and thicker for structural features.

Remember that these are minimums, not targets. Tall thin walls warp, flex, and break in shipping. If a feature matters structurally, give it generous thickness or add ribs. Embossed or engraved text should be at least 0.5 mm deep and wide, or it will disappear at print resolution.

Make Sure the Mesh Is Watertight and Scaled Correctly

A printable mesh must be watertight, meaning every edge is shared by exactly two triangles with no holes, gaps, or self-intersections. Sculpting tools and mesh editors often leave non-manifold geometry that slicers cannot interpret. Free tools like Meshmixer or the built-in repair in most CAD packages will flag and fix most of these errors.

Units matter just as much. STL files carry no unit information, so a part modeled in inches can arrive at our shop 25 times smaller than intended. Always confirm the export units and include a key dimension in your notes so we can verify scale before printing.

Common Mistakes That Slow Down Your Order

Beyond format and thickness, a few recurring issues delay quotes every week. Assemblies exported as a single fused body cannot move after printing, so leave at least 0.3 to 0.5 mm of clearance between mating or interlocking parts. Perfectly sharp internal corners concentrate stress, and a small fillet costs nothing digitally but adds real strength. Finally, tell us which surfaces and dimensions are critical. Knowing that a bore must fit a bearing or a face must stay flat lets us choose the right orientation and technology the first time.

Not Sure Your File Is Ready? Send It Anyway

File preparation should never be a barrier to getting your project moving. If you are unsure whether your model is printable, send it to us as is. We review every file by hand, repair minor issues at no charge, and flag anything that needs a design decision before we print. You can read more about our capabilities on our 3D printing service page at https://ecadcam.com/3d-printing/ or our product design page at https://ecadcam.com/product-design/ if the model still needs CAD work.

Ready to print? Request a quote from eCadCam in Los Angeles. Call us at 213.489.1173 or stop by our Glendale studio at 4212 San Fernando Rd, and we will get your parts moving.