Weak or Brittle Parts and Poor Layer Adhesion

Pro PCTG is much tougher than PETG when printed right. If parts snap, crack, or split along layer lines, the layers aren't fusing.

Fixes

1. Reduce cooling. Too much fan is the most common cause. Start with 5% minimum and 30–40% maximum, and increase minimum layer time.
2. Slow down so the plastic fully melts and each layer has time to bond.
3. Print hotter within 250–280°C.
4. Use our process profile, not a stock high-speed one.
5. Dry the filament.

A glossy surface means good bonding; matte bands mark weak spots. See Glossy vs. matte.

Design and orientation

• Parts are strongest when the load runs along the layer lines, not across them.
• About 4 walls and 30–60% infill help functional parts.
• For single-wall prints, thinner layers and a hotter nozzle improve bonding.

Fiber doesn't add toughness

Carbon fiber adds stiffness, not impact strength. For the toughest parts, use standard Pro PCTG. See Designing and printing for strength.

Still stuck? Contact our support team with photos, your printer and nozzle, your slicer, and any changes you made to our profile. A project file (.3mf) helps most.