How to 3D Print a Solder Paste Stencil
A step-by-step guide to creating precise SMD stencils from your Gerber files using an FDM 3D printer
A 3D-printed solder paste stencil, ready to use on a PCB.
What is a Solder Paste Stencil?
A solder paste stencil is a thin plate with cutouts that match the solder pads on your PCB. You place it over the board, spread solder paste with a squeegee, and the paste is deposited precisely on each pad.
Stencils are essential for SMD/SMT reflow soldering. They make the process faster and more consistent than applying paste by hand with a syringe.
3D Printed vs Professional Stencils
3D-printed stencils are a low-cost alternative ideal for prototyping and small batches. For final production boards with fine-pitch components, professional laser-cut stencils remain the reference.
| 3D Printed (Stenchill) | Professional (laser-cut) | |
|---|---|---|
| Cost | Free (just filament) | $15-30 per side |
| Turnaround | Minutes | Days (shipping) |
| Precision | Good (0.2-0.4mm nozzle) | Excellent (laser-cut) |
| Best for | Prototyping, small batches, 0603+ components | Fine-pitch QFN/BGA, production runs |
Close pads: what to do?
On fine-pitch footprints like QFN, QFP or SOIC, pads can sit so close together that the walls between them are too thin to print reliably. If you leave Merge close pads on (the default), I fuse each row into a single slot. If you turn it off, I stay true to the original layout and trust your slicer.
What You Need
- Gerber files from your EDA tool (KiCad, Eagle, Altium, or any other)
- An FDM 3D printer (any standard model works)
- PLA or PETG filament
- Solder paste and a squeegee
- Stenchill (this website) or the KiCad plugin
Step-by-Step Guide
Export your Gerber files
In KiCad, go to File → Plot, select Gerber format, and make sure the Paste layers (F.Paste, B.Paste) and Edge.Cuts are included. In Eagle or Altium, use the standard Gerber export. You need at least a Paste layer and the board outline.
Upload to Stenchill
Go to the Stenchill homepage, drag and drop your Gerber ZIP file, or use the individual files mode to select only the layers you need. You can also use the KiCad plugin to generate directly from the PCB Editor.
Adjust settings
Configure the generation parameters: stencil thickness (0.3-0.4mm recommended for most components), shrink value, nozzle diameter for automatic compensation of small pads, and shoulder options for PCB alignment.
The registration supports hold the stencil perfectly aligned on the PCB. They are generated automatically from the board outline.
Download and slice
Download the generated STL or 3MF file. In your slicer, use these settings: 0.1mm layer height, 100% infill, 3-4 layers total (matching your stencil thickness). A 0.2mm nozzle gives the best results, but 0.4mm works too with nozzle compensation enabled.
Slow your print speed to 30 - 40 mm/s. Stencils are tiny, fine-detailed prints, and slower toolhead movement gives the extruder time to lay down clean pad edges instead of skipping fine features.
If your slicer supports it (Cura, PrusaSlicer, OrcaSlicer, BambuStudio), switch the Wall generator from Classic to Arachne. Arachne adapts wall widths to the exact opening geometry and avoids the tiny gaps that Classic can leave on pads narrower than the nozzle. If your slicer only has Classic (older Slic3r derivatives, basic slicers), the stencil still prints - just with slightly less precision on the finest pads.
Print on a smooth bed surface (glass, smooth PEI, mirror). Because the face touching the bed mirrors its texture, a smooth bed gives you a perfectly flat side to spread solder paste across, and the squeegee glides without catching. Textured beds (textured PEI, granular surfaces) still work, but the imprinted bumps make paste harder to spread evenly.
In BambuStudio (shown), set Quality → Wall generator to Arachne before exporting G-code. Cura, PrusaSlicer and OrcaSlicer expose the same option.
Spread solder paste with a squeegee across the stencil openings, then carefully lift the stencil off the PCB.
Apply solder paste and reflow
Place the stencil on your PCB. The registration shoulders automatically align it. Spread solder paste across the openings with a squeegee. Remove the stencil carefully, place your SMD components, and reflow using a hot plate, reflow oven, or hot air station.
Tips & Troubleshooting
Paste bleeds under the stencil
Check that the stencil sits flat on the PCB. Use tape or clamps to hold it in place. Make sure the bottom surface is smooth (print on a glass bed).
Small pads don't print correctly
Use a 0.2mm nozzle for best results with fine-pitch components. If using a 0.4mm nozzle, enable nozzle compensation in Stenchill. It automatically enlarges pads that are too small for your nozzle.
Stencil warps after printing
Print on a heated glass bed for best flatness. PETG warps less than PLA. Make sure your first layer adhesion is good and avoid removing the stencil while it's still warm.
Shoulders don't fit the PCB
Increase the clearance parameter in the settings. The default 0.3mm works for most PCBs, but if your board is slightly oversized, try 0.5mm.
Pads printed partially filled or skipped
If your slicer supports it (Cura, PrusaSlicer, OrcaSlicer, BambuStudio), switch the wall generator to Arachne. It produces variable-width walls that fit narrow pad openings, whereas the Classic generator skips or under-fills walls thinner than the nozzle.
Ready to try?
Generate your stencil in seconds. It's free, no account required.