Printing with TPU (thermoplastic polyurethane) is entirely doable on most FDM 3D printers, but it requires slower speeds, adjusted settings, and a bit more attention to your filament path than rigid materials like PLA. The flexibility that makes TPU useful for phone cases, gaskets, and shoe insoles is the same property that makes it tricky to feed through an extruder. Here’s how to get clean, reliable prints.
Choose the Right Hardness for Your Printer
TPU filament is rated on the Shore A hardness scale, and that number directly affects how easy it is to print. Most “standard” TPU sold for 3D printing is 95A, which is the stiffest and most forgiving option. It still flexes, but it’s rigid enough to feed through an extruder without buckling constantly. This is where you should start if you’re new to flexible printing.
Softer TPUs in the 80A to 88A range are noticeably more flexible and still printable on many setups, though they demand more care with speed and filament path. Below 70A, you’re dealing with very soft, gummy material that realistically needs a direct drive extruder and extremely slow speeds to work at all. If your project doesn’t require extreme flexibility, stick with 95A for the most reliable experience.
Why Your Extruder Type Matters
The single biggest factor in whether your printer handles TPU well is the extruder design. Direct drive extruders, where the motor sits right on the print head, give you a short, straight filament path. That short route means precise control over extrusion and retraction, which is exactly what flexible filament needs.
Bowden extruders, where the motor is mounted on the frame and pushes filament through a long PTFE tube, are a different story. That long tube introduces friction and elasticity. Flexible filament tends to stretch, buckle, or stick against the tube walls, leading to inconsistent feeding or outright jams. You can print TPU on a Bowden setup (especially stiffer 95A), but you’ll need to go slower and accept that some stringing and feeding issues come with the territory.
If you’re using a printer with a reverse Bowden tube running from the spool to the extruder (common on machines like Bambu Lab printers), keep that tube as short as possible. Move the print head to the farthest point from the spool, then trim the tube so it just barely reaches. Mounting the spool directly above the printer so the filament feeds straight down also reduces friction significantly. Some users skip the PTFE tube entirely and mount the spool overhead for TPU prints.
Temperature Settings
Set your nozzle temperature between 210°C and 240°C. Starting at 225°C works well for most 95A TPU brands, and you can adjust from there. Too low and you’ll get poor layer adhesion and underextrusion. Too high and the material gets overly soft in the melt zone, which makes feeding problems worse.
Bed temperature is flexible: anywhere from 25°C to 60°C works, and many people print TPU successfully with no heated bed at all. TPU rarely warps, so bed adhesion is one of the easier parts of the process. If you do notice lifting at the corners, the culprit is usually a dirty build plate (oily fingerprints are common) or a bed that isn’t level, not a temperature issue.
Print Speed and Retraction
Speed is where TPU demands the most patience. For standard 95A TPU, print between 20 and 40 mm/s. That’s roughly half to a third of what you’d use for PLA. Rushing it causes the filament to buckle in the extruder or feed inconsistently, leading to gaps in your layers and potential jams. Some newer “high-flow” TPU formulations are designed for faster printing and can handle 40 to 100 mm/s, but standard TPU needs a slow, steady pace.
Retraction settings need a light touch. With a direct drive extruder, use a retraction distance of just 1 to 2 mm at a speed of 15 to 25 mm/s. Higher retraction distances that work fine for PLA will jam flexible filament by pulling it back into the drive gears where it can bunch up and clog. Some users disable retraction entirely for TPU and deal with the extra stringing in post-processing, which is a valid approach if jams are a recurring problem.
With a Bowden setup, you’ll typically need slightly higher retraction distances to compensate for the longer filament path, but keep increases small and test incrementally. The goal is finding the minimum retraction that controls stringing without causing jams.
Cooling and Layer Adhesion
Run your part cooling fan at 100%. Unlike materials such as ABS that need minimal cooling to avoid warping, TPU benefits from aggressive cooling. It needs to solidify quickly after being deposited to hold its shape, especially on overhangs and bridges. Full fan speed from the first layer onward is standard practice.
Dry Your Filament Before Printing
TPU absorbs moisture from the air, and wet filament causes bubbling, popping sounds during extrusion, rough surface texture, and poor layer bonding. If your TPU has been sitting out unsealed for more than a few days, dry it before printing. Use a filament dryer or a food dehydrator set to 40°C to 45°C for 4 to 6 hours. Don’t go above 50°C, as TPU softens at relatively low temperatures and you risk deforming the spool or fusing filament loops together.
After drying, store TPU in a sealed bag or container with desiccant packets. Printing from a dry box (an airtight container with a filament outlet) is even better for long prints, keeping the material dry throughout the entire job.
Common Problems and Fixes
Filament Jams or Stops Extruding
This is the most frequent TPU failure. The filament either buckles between the drive gear and the hot end, or the extruder can’t grip it firmly enough to pull it off the spool. Start by reducing friction in the filament path: shorten any PTFE tubing, straighten the path from spool to extruder, and make sure the spool spins freely. You can also slightly increase extruder tension (the pressure the gear applies to the filament), though this alone rarely solves the problem if the path has too much resistance.
Stringing Between Parts
Some stringing is nearly unavoidable with TPU. You can minimize it by dialing in the lowest retraction distance that still helps, reducing travel speed, and making sure your nozzle temperature isn’t higher than necessary. Thin strings on TPU parts clean up easily with a heat gun on a low setting or even just by pulling them off with your fingers.
Poor Surface Quality
If your prints look rough, bubbly, or have inconsistent layers, moisture is the most likely cause. Dry the filament and try again. If the surface looks good but layers aren’t bonding well, bump up the nozzle temperature by 5°C increments until adhesion improves.
Quick Reference Settings for 95A TPU
- Nozzle temperature: 210–240°C (start at 225°C)
- Bed temperature: 25–60°C (or unheated)
- Print speed: 20–40 mm/s
- Retraction distance: 1–2 mm (direct drive)
- Retraction speed: 15–25 mm/s
- Cooling fan: 100%
- Drying temperature: 40–45°C for 4–6 hours