Direct Ink Writing (DIW) on NanoPaper: Voltera Nova-Style Baselines

This page gives starting points for DIW printers (e.g., Voltera Nova). Exact values are ink- and tool-dependent—tune using your vendor’s rheology and cure guidance.

Substrate prep

Acclimate sealed packs ≥2 h at 40–60% RH, 18–24 °C.
Handle with nitrile gloves; avoid prints over fingerprints.
Mount sheets flat using low-tack frame tape; avoid stretching.

Tool & material setup (DIW)

Nozzles (ID): start 150–250 µm for traces; 300–410 µm for fills.
Z-offset: tip just kisses the surface (≤10 µm standoff). If the bead pearls, lower Z; if it scrapes, raise Z.
Ink conditioning: degas if recommended; equilibrate syringe to room temp; verify thixotropy (bead should slump minimally in 60 s).
Purge/prime: extrude a short line off-part; wipe; re-zero Z if needed.

Baseline process window (starting ranges)

Pressure / flow: 20–80 kPa (or vendor-specific units) for ~200–300 µm nozzles. Adjust until bead = ~1.1–1.4× nozzle ID.
Speed: 2–8 mm/s (narrow features slower).
Line spacing (infill): 0.8–1.0× measured line width for dense fills; 1.2× to avoid overfill.
Cornering & retract: enable small decel before corners; retract on travel to prevent stringing.
Platen heat (if available): 30–50 °C to reduce coffee-ring and help set; higher only if your ink allows.

Working rule: keep the aspect ratio (height/width) ~0.2–0.5 on first pass; add passes if you need thickness, not pressure.

Print a fast test coupon

Use the A4 Test Coupon (line/space arrays, pad grid, serpentine). Print:

One trace quality strip (single-pass) across multiple line widths.
One serpentine for resistance per length.
A small infill square (10 × 10 mm) at two different spacings.

Dry / anneal / sinter (ink-dependent)

Stage solvent removal first: 60–80 °C until mass change plateaus.
Anneal: 120–150 °C typical for many metal/polymer systems (check TDS).
Sinter (if applicable): follow vendor guidance; do not exceed substrate/ink limits.
Cool flat under a light, clean weight to minimize curl.

QC checklist (after cure)

Geometry: measure line width/height (optical or stylus). Edge acuity should be clean with minimal feathering.
Adhesion: tape or cross-hatch over pads; inspect for lift.
Electrical: 4-wire or Kelvin clips on the serpentine; record Ω/□ or Ω/mm.
Repeatability: print three lines at identical settings; stdev of width <5% is a good sign.

Common defects & fixes

Stringing between moves → increase retract, reduce pressure, add wipe on travel.
Bead flattening / skid → Z too low or pressure too high; raise Z 10–20 µm or lower pressure.
Under-extrusion gaps → raise pressure slightly, slow speed, verify nozzle isn’t clogged (sonicate/flush if allowed).
Coffee-ring edges → modest platen heat (30–50 °C), lower laydown per pass, increase inter-pass delay.
Corner bulges → enable corner slow-down; reduce acceleration jerk.

Parameter tuning sequence (efficient)

Z-offset: tune visually until bead contacts without scraping.
Pressure: adjust to get bead ≈1.2× nozzle ID.
Speed: raise until edges just start to degrade, then back off ~20%.
Spacing: set infill at 0.9–1.0× measured line width for solid areas.
Thermal: stage dry → anneal; only then evaluate electricals.

Design notes for DIW on NanoPaper

Favor continuous traces; minimize starts/stops on fine features.
For vias/pads, use dog-bone flares to reduce current crowding.
If stacking passes for thickness, let each pass set (warm platen or short dwell) before the next.
For connectors, plan landing pads ≥1.5× nozzle ID + tolerance.

Documentation to capture (per run)

Nozzle ID, Z-offset, pressure units + value, speed, spacing, passes.
Platen temp, cure profile, ambient RH/°C.
Measured width/height, adhesion result, resistance/length.
Substrate lot ID and ink lot.

Safety & handling

Follow ink SDS (solvents, nanoparticles).
Ventilate heated steps; avoid radiant hotspots.
Dispose of wipes/nozzles per local rules.

Handling & Storage
Screen Printing on NanoPaper
Technical Data Sheets (TDS)