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How to Prepare CAD Files for 3D Printing Bureaus
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How to Prepare CAD Files for 3D Printing Bureaus

By Keagan Walker (AI-assisted)•Published: 12 June 2026
Summary

High-quality 3D prints depend on properly exported CAD models. Using STEP files, exporting individual shells, and budgeting correct clearances prevents geometric errors and fits issues.

Smooth Data Transfer from Screen to Print

To get an accurate, fast quote from a 3D printing bureau like NovaLab 3D, exporting your CAD data correctly is the most important step. A poorly exported file can result in faceted curves, incorrect scale, missing holes, or components that fail to slice.

This guide outlines how to configure your CAD exporter to ensure your designs transition smoothly from your screen to our Pickering facility.

Key Takeaway

Export files in STEP format whenever possible. If you must use STL, set export resolutions carefully to avoid visible facets on curved surfaces.

1. The File Format: STEP vs. STL

Traditionally, STL was the industry standard for 3D printing. However, STL files represent surfaces as collections of triangles, which discards the original mathematical curves of your CAD model.

  • STEP (Recommended): A STEP file preserves the true mathematical geometry (B-Rep) of your design. Our slicers can read STEP files directly and generate incredibly smooth toolpaths, avoiding faceted perimeters on holes and cylinders.
  • STL (Fallback): If you must export to STL, ensure your exporter resolution is set to 'Fine' or 'Custom' with a chord deviation of around 0.01mm.

2. Sizing and Units

STL files are unitless. The file simply contains numbers like "50", which the slicer must interpret.

  • Standard Unit: The vast majority of 3D printing slicers operate in millimetres (mm). Ensure your CAD software exports using millimetres as the baseline unit. If you export in inches, your 2-inch bracket will load into our slicer as a tiny 2mm speck.
  • Explicit Scale: If your part was designed in inches or meters, let us know in the quote description so we can apply the correct scaling factor.

3. Handle Assemblies Separately

Do not export a complex multi-part assembly as a single STL file. The slicer will merge the overlapping geometries into a single solid mass, making it impossible to print them as separate components or assemble them later.

  • Export each individual component as a separate file.
  • If parts fit together, include an assembly drawing or name files logically (e.g. housingbase.step and housinglid.step).

Secure CAD Upload

At NovaLab 3D, we accept STEP, STL, and major native CAD files securely. We treat all client data as strictly confidential. Upload your files today for a professional engineering review.

Frequently Asked Questions

STEP files contain true mathematical curves and NURBS data, which our slicers translate directly into smooth toolpaths. STL files tessellate surfaces into flat triangles, which can leave visible facets on curved walls.

For interlocking or rotating assemblies, design a clearance gap of at least 0.2mm to 0.3mm to ensure they don't fuse together during printing.

No, export each individual component as a separate file. This allows us to orient each part independently for optimal print strength and surface finish.

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Keagan Walker

Founder & Lead Designer

NovaLab 3D is a boutique engineering and additive manufacturing studio based in Pickering, North Yorkshire. We provide B2B clients and product developers with direct access to lead engineering consulting, fast 48-hour turnarounds, and custom FDM production runs.