Sagging

11 min

Sagging

Features drooping down after thermal curing (baking).

How to Identify

Sagging can be diagnosed as follows:

Thin walls, overhangs, and large surfaces look fine after printing but are sagging down, relative to their baking orientation, after thermal curing.

Cause - Inconclusive

Troubleshooting

It is recommended that you review all the possible solutions before taking action to ensure you are pursuing the best course of action.

If the best course of action is not apparent, try the troubleshooting options in the order listed. Refer here for more tips.

Process

If any of these conditions apply to your print, take the corrective action and reprint to see if the problem is resolved.

Change the baking method to provide support to sagging features.

Reorient

Change the baking orientation to place delicate features and overhangs overhangs on their side.

Pack Parts in Salt

Salt provides support to thin and delicate features.

With compatible resins, salt is effective to temporarily fixture the part during thermal curing.

Reference Salt Baking for more information.

Leave Supports

The supports used during printing can be baked with the part if

Supports are accessible to remove with a cutting tool.
The material is soft enough to cut with a hand tool after baking. ie an elastomer

Baking Fixture

Create a baking fixture to hold features in place during baking.

You can design and print a baking fixture in a material that can withstand the high temperatures of baking, such as Loctite IND147.

Print Preparation or Part Design Adjustments

The following solutions will address print or part-related causes of the defects. Choose among the suggested actions below and select the best approach for your application. Usually only one type of adjustment is needed.

Increase Thickness

Increase thickness of and/or shorten overhangs.

Add Structure

Add fillets, bevels, or chamfers to increase strength at features too weak to support their weight.

If problems persist, please reach out to Carbon Support.

Explanation & Causes

Explanation

Unsupported thin walls, overhangs, and large surfaces sag under their own weight.

During thermal curing, parts temporarily soften as their polymer structure reforms into their final mechanical state.
Thin, unsupported features sag in this softened state and remain in that position when final material properties are reached.

Causes

Post-Processing

How the part is handled in post-processing is causing the defect.

Root Issue	Problem	Why Defect Presents
Weak Features	Features not supported	Thin features with overhangs too long to support their own weight will sag when in a temporarily softened state during baking.

Print Preparation or Part Design

How the part is oriented, supported, or designed is causing the defect.

Root Issue	Problem	Why Defect Presents
Weak Features	Thin and fragile features	Thin features with overhangs too long to support their own weight will sag when in a temporarily softened state during baking.