TPU insole printing.
The settings that actually hold up.
Printing insoles in flexible TPU is easy to get wrong: stringy, under-extruded, or peeling off the bed. This guide is how to dial in TPU insole printing, with the exact slicer settings, the prep that prevents most fails, fixes for the ones that slip through, and how to finish with a top cover. Bring your own STL, or generate one in minutes.
TPU insole print settings that work.
A solid starting profile for printing insoles in flexible TPU on a direct-drive FDM printer. Treat it as a baseline and tune from here to your filament and machine, since TPU brands vary in the temperature and flow they like best.
| Setting | Value | Why |
|---|---|---|
| Material | TPU 95A | Flexible and fatigue-resistant — cushions and rebounds for daily wear. |
| Nozzle temp | 220–235 °C | Enough flow for clean flexible extrusion; drop it if you see stringing. |
| Bed temp | 30–45 °C | Light heat helps the first layer stick without over-softening. |
| Nozzle | 0.4 mm | Standard; no special hardware needed for plain TPU. |
| Speed | ~30 mm/s | Slow and steady keeps the soft filament feeding cleanly. |
| Infill | 20% gyroid | Flexes and rebounds evenly in all directions — the cushioning structure. |
| Walls | 3 perimeters | Shell strength and a clean surface over the infill. |
| Layer height | 0.2 mm | A balance of print time and a smooth top surface. |
| Flow | ~103–105% | A touch of over-extrusion fills flexible gaps for a solid feel. |
| Retraction | Low / minimal | TPU oozes; keep retraction short (or off on direct drive) to avoid jams. |
Direct-drive extruder strongly recommended. Flexible TPU feeds unreliably through long Bowden tubes. A Bambu Lab, Prusa MK-series, or Voron-style direct-drive setup handles it far better; on Bowden, slow down and tune retraction carefully.
Four things to set up first.
Most TPU insole failures are decided before the first layer. Five minutes of prep saves a scrapped six-hour print, and gets these four right so the settings above can do the rest.
TPU absorbs moisture
A damp spool spits, strings, and pops during printing. Dry TPU in a filament dryer at about 50 °C for 4 to 6 hours before you print, and keep it dry while it runs.
Feed the soft filament cleanly
A direct-drive extruder pushes flexible TPU far more reliably than a long Bowden tube. On Bowden, slow right down and tune retraction, or expect jams on longer prints.
Clean plate, light heat
Wipe the plate so it's grease-free, set the bed to 30 to 45 °C, and add a brim. TPU sticks well to a clean PEI or textured plate, sometimes almost too well.
Lay it on its base
Print the insole flat, base down. A standard insole shape has no steep overhangs, so it needs no supports. That keeps the underside clean and cuts print time and filament.
Fixing the four common TPU insole print fails.
Almost every failed TPU insole comes down to one of these four issues. Here's the symptom, the likely cause, and the fix for each, so you can diagnose a bad print at a glance instead of guessing and reprinting.
Wispy strands across the print
Nozzle too hot, retraction too low, or wet filament. Fix: drop nozzle temp in 5 °C steps, add modest retraction, and dry the TPU (spool in a dryer or low oven) before printing.
Gaps, thin walls, weak feel
The soft filament is slipping or the flow is too low. Fix: slow to ~30 mm/s, nudge temp up 5 °C, raise flow toward 105%, and check the extruder tension — direct drive helps most here.
Corners peel off the bed
Poor first-layer adhesion. Fix: clean the bed, add a little bed heat (30–45 °C), slow the first layer, and use a brim. TPU normally sticks well once the plate is clean.
Splits between layers under flex
Layers aren't bonding — too cool or too fast. Fix: raise nozzle temp, slow down, bump flow slightly, and turn part-cooling fans down so layers fuse.
Add a top cover for feel.
A printed TPU insole works bare, but a thin top cover changes the feel underfoot and protects the printed surface from wear. Common choices are EVA foam (soft and cheap), fabric or microfiber (breathable and grippy), and leather or suede (a premium feel). A 1.5 to 3 mm cover is typical: thicker adds cushioning but eats into shoe volume, so match it to the shoe you'll actually wear the insole in.
Gluing it on, cleanly
Use a contact adhesive, apply a thin even coat to both surfaces, and let it tack until touch-dry, then press from the heel forward to push out bubbles. Trim the cover flush once the glue has cured, not before. For durometer choices by activity and a full top-cover walkthrough, see the TPU hardness & top-cover guide.
Don't have an insole STL yet?
These settings will print any insole STL, but the fit is what makes it worth wearing. A generic marketplace STL isn't shaped to your foot; a fitted one is. Generate a custom insole in Ergono3D from a guided foot profile (no CAD, no scanner), preview it in 3D, and export a print-ready STL to run with the settings above. Left and right come as a matched pair, and you can re-export after a wear test.
TPU insole printing questions, answered.
/ 01What TPU hardness should I use for insoles?
Around 95A shore is the common all-round choice — flexible but supportive. Softer (85A–90A) gives more cushioning for recovery or standing; firmer stays closer to 95A for running and support. See the TPU hardness & top-cover guide for choosing by activity.
/ 02Do I need a direct-drive extruder to print TPU insoles?
A direct-drive extruder is strongly recommended for flexible TPU — it feeds the soft filament reliably. Bowden setups can print TPU but need slower speeds and careful retraction tuning to avoid jams.
/ 03Why is my TPU insole stringing?
Stringing usually means the nozzle is too hot, retraction is too low, or the filament has absorbed moisture. Drop the nozzle temperature in 5 °C steps, enable modest retraction, and dry the TPU before printing.
/ 04What infill should I use for a TPU insole?
About 20% gyroid infill is a good starting point. The gyroid pattern flexes and rebounds evenly in every direction, which is what lets a printed insole cushion and spring back over thousands of steps.
/ 05How long does a pair of TPU insoles take to print?
Roughly 5–7 hours for a pair, depending on insole size, layer height, and print speed (around 30 mm/s for clean flexible extrusion).
/ 06Can I print insoles on a Bambu Lab or Prusa printer?
Yes. Bambu Lab, Prusa, and most modern FDM printers that handle flexible filament can print TPU insoles. Load a print-ready insole STL, apply the TPU settings above, and print.
/ 07Do TPU insoles need supports?
No, not for a standard insole shape. Printed flat on its base, an insole has no steep overhangs that need support. Skipping supports saves time and filament and keeps the underside clean.
/ 08Which TPU brand should I use?
Any reputable 95A TPU prints well. Whatever brand you pick, dry the spool first and tune the nozzle temperature to that filament, since brands differ by 10 to 15 °C. Consistency of diameter matters more than the label.
/ 09How do I dry TPU before printing?
Run the spool in a filament dryer at around 50 °C for 4 to 6 hours, or a low oven if you trust its thermostat. Dry filament is the single biggest fix for stringing and surface popping on TPU.
Print insoles that actually hold up.
Generate a custom insole STL, run these TPU settings, and you've got a wearable pair for a few dollars of filament — no CAD, no scanner, no lab.
Custom insole STL generator
Generate a print-ready insole STL from a guided profile — no CAD.
TPU hardness & top covers
Pick durometer by activity and finish the print for the right feel.