Overhang Issues

The Problem

An overhang is any part of the print that is printed at an angle to the vertical, without direct support underneath. The problem occurs when these sections have a very poor finish, with drooping lines, upward curling, or improper adhesion.

A close-up of an angled overhang on a 3D print showing drooping loops and a rough, messy surface finish due to poor cooling.

Common Causes and How to Fix Them

Like bridging, good overhang performance depends almost exclusively on cooling the filament as quickly as possible so it solidifies before it has time to droop or deform. Most stock printers can handle angles up to 45-50 degrees without issue. Above that, quality begins to degrade.

1. Insufficient Cooling

This is the main cause. If the airflow from your part cooling fan is not powerful or well-directed, the plastic will remain soft for too long.

• Fix 1 (Slicer): Ensure your Fan Speed is at 100% for materials like PLA. Check if your slicer has an option to Increase fan speed for overhangs.
• Fix 2 (Hardware): The most significant improvement comes from installing a more efficient cooling duct (fan duct). Designs that offer dual-sided or 360° cooling (like the Satsana) make a huge difference.

2. Printing Temperature Too High

Printing hotter makes the plastic more liquid, making it more susceptible to drooping under gravity.

• Solution: Lower the printing temperature. Use the lowest temperature in the recommended range for your filament that still gives you good layer adhesion. A Temperature Tower is the ideal tool to find this point.

3. Printing Speed Too High

Printing overhangs quickly doesn't give the cooling fan enough time to act.

• Solution: Most slicers have specific speed settings for overhangs. Enable this feature and configure it to drastically reduce speed based on the overhang angle. For example:
  • 25% incline -> 80% speed
  • 50% incline -> 60% speed
  • 75% incline -> 40% speed

4. Layer Height Too Large

Larger layer heights (e.g., 0.28mm or 0.32mm) create more difficult overhangs because the overlap between one layer and the next is smaller.

• Solution: If overhang quality is critical, use a smaller layer height (e.g., 0.12mm or 0.16mm). Thinner layers get more support from the previous layer, allowing for steeper angles.

Quick Checklist

• Increase the part cooling fan speed to 100%.
• Print and install an improved cooling fan duct.
• Lower the printing temperature by 5-10°C.
• Enable and configure overhang-specific print speeds in the slicer.
• Use a lower layer height for critical overhangs.
• If the angle is greater than 60-70 degrees, consider using supports.