When preparing a part for printing, there is one element that almost never appears in the design but that determines the final result: supports. These are temporary structures that are created alongside the part and removed afterward, and the finish, print time, and cost depend largely on them.

Understanding when supports are truly necessary in 3D printing and how to reduce them during the design phase is one of the simplest ways to improve the quality of a part without changing the material. In this article, we’ll explore when they’re needed, which technologies eliminate them, and how to minimize the marks they leave behind.

What are 3D printing supports, and what are they used for?

Supports are auxiliary structures that hold up the parts of a piece that cannot be manufactured in mid-air. In technologies that deposit or cure material layer by layer, each new layer needs to rest on something: if there is nothing underneath, the material sags, warps, or simply cannot hold itself up.

In addition to supporting overhangs, in some processes they serve a second purpose: anchoring the part to the platform and dissipating heat. This is the case with 3D metal printing, where supports prevent thermal stresses from deforming the geometry during the process.

La regla de los 45°: cuándo son necesarios los soportes

The most commonly used guideline for determining whether an area needs support is the 45° rule. As long as a wall is inclined less than 45° from the vertical, each layer rests sufficiently on the one below it, and the structure supports itself. Beyond that angle, the overhang begins to need support.

In addition to cantilevers, there are three situations that almost always require support:

• Long spans between two supports: FDM works well for short spans, but the quality decreases as the distance increases.
• Islands: areas that begin in the air, with nothing beneath them to rest on.
• Large-diameter horizontal holes, the upper half of which is cantilevered.

Not all 3D printing technologies require supports

One of the most influential factors is the technology itself. In FDM and SLA or resin printing, support structures are unavoidable whenever overhangs are present. In SLA, it is also advisable to include drainage holes in hollow parts to prevent suction effects during the process.

In contrast, powder-bed technologies such as SLS and Multi Jet Fusion (MJF) do not require support structures: the unmelted powder surrounding the part supports it throughout the entire printing process. This allows for geometries that are impossible with other technologies, such as internal channels or pre-assembled components, and eliminates support marks entirely.

How to Design Parts That Require Fewer Supports

Much of the work is done before printing. These adjustments are part of design for manufacturability (DFM) and reduce material usage, time, and post-processing:

• Replace sharp overhangs with chamfers that are at a 45° angle.
• Design the horizontal holes to be teardrop- or diamond-shaped instead of circular: this way, the top part is no longer a cantilever.
• Add rounded corners and smooth transitions instead of right-angle protrusions.
• If a single orientation doesn’t solve all the faces, consider splitting the piece and putting it back together later.

The orientation of the piece: the decision that has the greatest impact

Before adding a single support, it’s a good idea to decide how the part will be positioned in the machine. The orientation determines which surfaces will be overhanging, how many supports are needed, and, most importantly, where the support marks will be located.

The rule of thumb is simple: position the part so that the supports touch the least visible or least critical surfaces. An aesthetic surface, a fitting area, or a surface with important dimensions should not rest on a support if it can be avoided.

How to Minimize Support Marks

When support is unavoidable, the goal becomes to leave as little trace as possible:

• Reduces the contact area: fine tips and lower density at the interface make removal easier and leave fewer marks.
• Use tree-shaped supports: they make contact with the part at far fewer points and save material.
• Consider soluble supports in FDM (PVA or HIPS): they dissolve rather than being pulled away, making them ideal for delicate geometries.
• Adjust the Z-axis clearance: if it’s too close, it’s hard to remove; if it’s too far apart, it affects the finish of the bottom surface.

After that, post-processing takes care of the rest: sanding, shot blasting, or various surface finishes remove any residual marks when appearance matters.

Print your parts with Proto&Go!

Support structures aren’t a problem in and of themselves—they’re the result of specific geometry and orientation. Anticipating them during the design phase saves time, material, and post-processing, and results in cleaner parts the first time around.

At Proto&Go!, we review your 3D file, determine the proper orientation, and recommend the technology that best suits your part, including MJF printing, which doesn’t require supports.

Upload your file and get your quote online in less than 24 hours.