Bed Adhesion Tricks for PETG and TPU: A Guide for UK Makers and RC Pilots

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Introduction

When working with flexible and durable filaments like PETG and TPU, one common challenge is getting your 3D prints to stick properly to the print bed. Poor bed adhesion can lead to warping, failed prints, or rough first layers, which is frustrating for any maker or RC pilot aiming for precision parts. This guide covers practical tips and tricks to improve bed adhesion for PETG and TPU, helping you get smoother, more reliable prints every time.

Understanding PETG and TPU Characteristics

PETG (Polyethylene Terephthalate Glycol) combines good strength and flexibility, while TPU (Thermoplastic Polyurethane) is highly flexible and elastic. Both materials tend to be a bit trickier than PLA when it comes to bed adhesion because of their flexibility and different thermal properties.

Key Challenges

  • TPU’s flexibility can cause it to lift or warp if not secured properly.
  • PETG can stick too well to certain surfaces, risking damage to the print bed.
  • Both require careful temperature control to avoid warping.

Bed Preparation Tips

1. Clean the Bed Thoroughly

Oils and dust are your worst enemies. Use isopropyl alcohol or warm soapy water to clean the print surface before every print. This ensures better contact between the filament and the bed.

2. Choose the Right Print Surface

For PETG, a glass bed with a thin coat of glue stick or a PEI sheet works well. TPU often adheres better to a textured surface like BuildTak or a flexible steel sheet with a PEI coating.

3. Use Adhesives Sparingly

If you’re having trouble, applying a thin layer of PVA glue stick or hairspray can help. For PETG, avoid anything too sticky to prevent damage to the bed. TPU benefits from a slightly tacky surface but test first on small prints.

Printer Settings for Better Adhesion

1. Bed Temperature

Set your heated bed between 60-75°C for PETG and 40-60°C for TPU. Too low and the filament won’t stick; too high and you risk warping or stringing.

2. First Layer Height and Speed

A thicker first layer (around 0.2-0.3mm) helps the filament stick better. Slow down the first layer speed to about 15-20mm/s to allow the filament to bond firmly.

3. Nozzle Distance

Ensure the nozzle is close enough to the bed — a good “squish” of filament against the surface is ideal. Too high and the filament won’t stick; too low and it may clog or create uneven extrusion.

Additional Tips and Tricks

  • Brims and Rafts: Adding a brim can increase surface area and prevent edge lifting, especially useful for TPU parts.
  • Enclosure: Printing in a warm environment or using an enclosure helps maintain stable temperatures and reduces warping.
  • Cooling Fan: Turn off or reduce the cooling fan for the first few layers to improve adhesion.
  • Test Prints: Always try small test prints when adjusting new settings to save time and filament.

Conclusion

Mastering bed adhesion with PETG and TPU requires a bit of patience and experimentation but following these tips should give you a solid foundation. Clean your bed, use the right surface and adhesives, dial in your temperatures and print speed, and consider brims or enclosures when needed. With these tricks, your flexible and durable prints will stick well and come out beautifully every time.

Happy printing and safe flying!

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