Bed Adhesion Tricks for PETG and TPU: A Maker’s Guide

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Introduction

If you’re into 3D printing for RC models or DIY projects, you’ve probably worked with PETG and TPU filaments. Both offer great flexibility and strength but can be tricky when it comes to bed adhesion. Poor adhesion can lead to warping, failed prints, or wasted material. This guide will walk you through simple, effective tricks to improve bed adhesion for PETG and TPU, helping you get cleaner prints and less frustration.

Understanding PETG and TPU

PETG (Polyethylene Terephthalate Glycol) is a strong, slightly flexible filament that combines the best of PLA and ABS. TPU (Thermoplastic Polyurethane) is a flexible, rubber-like filament used for parts that need to bend or absorb shocks — perfect for RC pilots wanting durable components.

Both materials require specific bed preparation and print settings to stick well during printing.

Common Challenges with Bed Adhesion

Both PETG and TPU tend to be less forgiving than PLA. PETG can stick too well and damage the bed surface if not careful, while TPU’s softness makes it prone to shifting or lifting during the print. Here’s how to tackle these challenges.

Bed Preparation Tips

  • Clean the Bed: Always start with a clean print surface. Use isopropyl alcohol or warm soapy water to remove oils or dust.
  • Use a Suitable Surface: For PETG, a PEI sheet or glass bed with a glue stick works well. TPU prefers a flexible build plate like PEI or textured tape.
  • Avoid Blue Painter’s Tape: While common for PLA, it doesn’t hold PETG or TPU well.
  • Apply Adhesives Carefully: A thin layer of PVA glue stick can improve adhesion without causing excessive sticking, especially with PETG.

Print Settings Adjustments

Fine-tuning your slicer settings is just as important as bed prep.

  • Bed Temperature: Set PETG bed temperature between 70-80°C. TPU generally prints better with a heated bed around 50°C.
  • First Layer Speed: Slow down the first layer to 20-25 mm/s to give the filament time to bond.
  • First Layer Height: Increase the first layer thickness slightly (e.g., 0.2-0.3 mm) to improve surface contact.
  • First Layer Flow Rate: Boost flow rate by 5-10% for better adhesion.
  • Use a Brim or Raft: Adding a brim (5-10 mm wide) helps stabilize TPU prints that might otherwise lift.

Additional Tips for TPU

  • Reduce Retraction: TPU is flexible and can jam if retracted too much; keep retraction minimal.
  • Lower Print Speed: TPU prints best at slower speeds around 20-30 mm/s.
  • Use a Direct Drive Extruder: Flexible filaments like TPU feed better through direct drive setups than Bowden extruders.

Summary

Getting good bed adhesion with PETG and TPU is all about preparation and patience. Clean your bed, pick the right surface, adjust your temperatures, and tweak your first layer settings. For TPU, slow down and consider a brim to keep prints stable. With these tricks, your RC parts and custom projects will come out looking strong and professional every time.

Happy printing, and may your models stick perfectly!

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