Poor Surface Above Supports

If your model includes steep overhangs or areas with nothing beneath them, support structures can provide the necessary foundation for these layers. These supports are designed to be removable and separate easily from the finished part. However, you might need to tweak your settings to achieve the best surface quality above these support structures. Below are vital settings to adjust to improve the surface finish in these areas.

Common Causes and Solutions

Lower Your Layer Height
Reducing your layer height can enhance the performance of overhangs. For example, decreasing the layer height from 0.2mm to 0.1mm doubles the number of layers, allowing your printer to handle overhangs more effectively. With a 0.2mm layer height, you might need supports for overhangs above 45 degrees, but this could improve to 60 degrees with a 0.1mm layer height. This adjustment not only helps in smoothing the underside of your part but also reduces print time and support material. Start by experimenting with this setting to improve print quality.

Adjust Support Infill Percentage
Similar to the interior of your part, you can control the density of your support structures by modifying the support infill percentage. Typical values range from 20-40%, but increasing this percentage can help if the bottom layers of your part are sagging. Many creators prefer dense support structures, which allow for a lower infill density throughout most of the supports but increase density near the top to enhance stability.

Vertical Separation Layers
Balancing the support provided to your model with ease of removal is crucial. Too much support can cause the structures to bond with the part, making them difficult to remove, while too little support can result in an inadequate foundation. Typically, using 1-2 vertical separation layers is recommended when using the same material for both.

Horizontal Part Offset
The Horizontal Offset setting controls the distance between your part and the support structures. While Vertical Separation Layers prevent bonding on the top, the Horizontal Offset prevents bonding on the sides. A common value is 0.2-0.4mm, but you might need to adjust this based on your specific extruder and filament to achieve optimal results.

Use a Second Extruder
If your printer has multiple extruders, using a different material for supports can significantly improve the quality of your prints. For example, printing the model in PETG with PLA for supports can reduce bonding, making the supports easier to remove. When using a different material, you can often set the Upper Vertical Separation Layers to zero and the Horizontal Offset to around 0.1mm.