Supports in 3D Printing: When You Need Them and When You Don't

Supports in 3D printing are a double-edged sword. They can save a print from failing due to overhangs or complex geometries, but they also add material, time, and post-processing work. Knowing when to use supports—and when to avoid them—can significantly improve your 3D printing workflow. This guide covers the essentials for FDM and resin printing, material considerations, slicing techniques, and design tips to minimize or eliminate the need for supports.

What Are 3D Printing Supports?

Supports are temporary structures added during printing to hold up overhangs, bridges, or other features that would otherwise collapse under gravity. In FDM printing, supports are typically printed in the same material as the object, while resin printers often use a different support material or structure. Supports are generated by slicing software, but their effectiveness depends on proper design and settings.

Supports come in two main types: tree and linear. Tree supports are branching structures that touch the model at fewer points, reducing surface damage. Linear supports are grid-like and provide more stability but often leave marks. Choosing the right type depends on the geometry of your model and your post-processing capabilities.

When You Need Supports

Supports are necessary when a part of your model extends horizontally beyond a certain angle—usually 45 degrees in FDM printing. Without supports, the material will droop or fail entirely. Complex geometries like arches, bridges, or intricate lattice structures also require supports to maintain their shape during printing.

In resin printing, supports are almost always needed for overhangs, as the liquid resin lacks the structural integrity to hold itself up during curing. Resin supports are finer and more delicate than FDM supports, but they are crucial for preventing warping or detachment from the build plate. Even small features like text or fine details may require supports in resin prints.

When You Can Avoid Supports

Not all prints need supports. If your design avoids overhangs greater than 45 degrees, you can often print without them. This is especially true for FDM printing, where careful orientation and design tweaks can eliminate the need for supports. For example, rotating a model so that overhangs become vertical layers can save time and material.

In resin printing, supports are harder to avoid, but their impact can be minimized. Positioning the model at an angle reduces the number of supports needed and improves surface quality. Hollowing out large models also reduces material use and makes supports easier to remove. Always consider the trade-offs between print time, material use, and post-processing effort.

Material Considerations

The material you use affects whether supports are necessary and how easy they are to remove. PLA, for example, has good bridging capabilities and can often print small overhangs without supports. ABS and PETG are less forgiving and may require supports even for minor overhangs. In resin printing, flexible resins are more prone to warping and often need more extensive supports.

Support material should also match the properties of the main print material. In FDM printing, using the same material for supports and the model simplifies the process, but dual-extrusion printers can use dissolvable supports like PVA for easier removal. Resin printers typically use the same resin for supports, but some advanced systems allow for different support materials.

Slicing Software Settings

Slicing software plays a critical role in generating supports. Key settings include support density, interface layers, and overhang angle. Higher support density provides more stability but increases material use and print time. Interface layers create a smoother surface where supports touch the model, making post-processing easier.

Overhang angle determines where supports are added. A lower angle generates more supports, while a higher angle reduces them but risks print failure. Experiment with these settings to find the right balance for your model. Advanced slicers also allow for custom support placement, letting you add supports only where necessary.

Design Tips to Minimize Supports

Good design can reduce or eliminate the need for supports. For FDM printing, chamfers and fillets can help transition overhangs into printable angles. Splitting a model into multiple parts that can be assembled later also reduces complexity and support requirements. In resin printing, adding small support handles or tabs can make removal easier without compromising the final product.

Hollowing out large models reduces material use and makes supports easier to remove. Adding drainage holes prevents trapped resin from causing cracks or leaks. Always test your design with slicing software before printing to identify potential issues and optimize support placement.

Post-Processing Supports

Removing supports can be time-consuming and risks damaging the model. For FDM prints, using pliers or a hobby knife carefully removes supports, but sanding or filing may be needed to smooth the surface. Dissolvable supports simplify this process but require access to dual-extrusion printers and compatible materials.

In resin printing, supports are often finer and easier to remove, but they can leave small marks. A UV curing station helps harden the resin and makes supports easier to snap off. Sanding or polishing resin prints improves surface quality but requires care to avoid damaging delicate details.

For complex models that require minimal post-processing, consider using Creomatrix’s on-demand 3D printing service. Their expertise ensures optimal support placement and high-quality prints, saving you time and effort.