- The slicer never sees your CAD model, only the mesh you exported from it, and it reproduces that mesh faithfully whether or not it still matches the surface you drew.
- Surface deviation around 0.1 mm with normal deviation at 10 degrees or less is the working band, and maxing the sliders only bloats the file without improving the print.
- Export Binary rather than ASCII, and confirm the unit type in the export dialog, because a unit mismatch produces a dimensionally perfect part at entirely the wrong scale.
- Serial numbers, tool identifiers, and revision marks belong on vertical walls in a uniform sans-serif face, never on the first layer.
- A minimum font width of 0.4 mm on walls and an emboss depth of 0.25 mm keeps marking legible and free of supports.
The slicer only ever sees your mesh
A print job passes through three sets of hands before it becomes a part: your CAD model, the mesh you export from it, and the toolpath our slicer builds from that mesh. Most of the attention goes to the first and the last. However, the middle step is where fidelity is won or lost: the slicer never sees your CAD geometry, only the triangles you handed it, and it reproduces those triangles faithfully whether or not they still resemble the surface you drew.
The two settings that carry most of that weight sit in the same export dialog. Surface Deviation governs how far a flat triangle may sit from the curved surface it stands in for, while Normal Deviation, sometimes labeled angular tolerance, governs how much the facet angle may swing from one neighbor to the next. Around 0.1 mm of surface deviation, with normal deviation held at 10 degrees or less, is the working band for the parts we run: fine enough that curvature still reads as curvature, loose enough that the file stays workable.
Two ways a good model exports badly
While maxing every resolution slider feels like diligence, it is among the more common things done to an otherwise clean model. Pushing resolution to its limit produces an enormous file that slows the slicer without improving anything the printer can resolve, since the machine lays down beads of Onyx rather than mathematical surfaces. Exporting Binary instead of ASCII is the free half of the fix, because the geometry is identical and the file is significantly smaller. Before you save, the Preview Mesh function in your CAD package shows exactly how the export is triangulating the surface. That turns the whole question into something you can look at rather than guess at.
The setting that does the real damage is the one nobody checks. Unit type at export has to match what the slicer expects, and a model authored in millimeters but written out in inches arrives dimensionally perfect and entirely the wrong size, with nothing downstream to flag it, because a wrong-scale part is still a valid mesh. It surfaces late, usually when someone sets calipers on a finished part, and confirming the unit selection costs a second that can remove the most expensive failure in this workflow.
Marking is a design decision
For most parts, marking is the last thing added to the model, and it behaves like the first thing that fails. Serial numbers, tool identifiers, and revision marks all have to survive the process that puts them there, which makes placement a geometry decision rather than a labeling one. The highest resolution and the best legibility come off the vertical walls. The bottom build surface is the one place text does not belong: the first layer is the most critical in the print, and text there adds complexity exactly where you can least afford it.
Marking rules we design to
Place text on vertical walls first, on roofs only when geometry leaves no choice, and never on the first layer. Use uniform sans-serif faces such as Rubik, Helvetica, or Arial, since serif faces vary line weight across a single glyph and that variation prints as a defect. Hold a minimum font width of 0.4 mm on walls and 0.6 mm on roofs, and emboss or deboss 0.25 mm deep, a depth shallow enough that no supports are needed. Embossing generally prints better than debossing, and roof text is the exception that needs more: emboss it, raise the width to at least 1 mm, and give it a depth of two to four layers.
These marks earn their place over the life of the tool. A tool identifier embossed into the wall of a fixture can survive handling, cleaning, and years on a shop floor in a way an adhesive label does not, and it lets an operator pull the right part off a shelf without measuring it. When you come back for an exact replacement print, the revision mark is the fastest way to confirm which version we are reprinting.
Before you send the file
Overall, both of these decisions are made in your CAD session and cannot be recovered in ours: a mesh exported too coarse cannot be re-refined by the slicer, and text placed on the first layer cannot be moved to a wall without a new export. Both take under a minute to get right. Export binary, hold surface deviation near 0.1 mm and normal deviation at 10 degrees or less, confirm the unit type, and preview the mesh before you save it.
With identifiers on a vertical wall at 0.4 mm minimum width and 0.25 mm emboss depth, the mark comes off the machine as geometry rather than as a finishing step. None of this changes where a part sits on the cost curve; it decides whether the part that arrives is the one you drew. Our engineering review runs the same business day, and there is no tooling charge and no minimum order to work against while you iterate. Everything downstream of that file is ours to manage, and a printed part will only ever be as good as the mesh it was sliced from.
Let us read your file before it becomes a part.
Send the drawing, the STL, or the part itself. The product or service, configuration, quantity, and service tier you select build an instant quote, engineering review confirms manufacturability and final construction the same business day, and there is no tooling charge and no minimum order.