Supports in 3D Printing: Stabilization Strategies Across Technologies

If you've used hand tools, you probably understand the value of a good vise or clamp, especially when none are available and you're forced to improvise. In additive manufacturing, support structures serve this critical workholding function, ensuring part stability throughout the complex 3D printing process.

In traditional manufacturing, the process of keeping a workpiece in a stable position during an operation is called workholding. It is absolutely critical to the vast majority of manufacturing processes, as evidenced by the fact that many people's careers are focused entirely on designing jigs, fixtures, clamps, vises and other highly customized tools for keeping a workpiece in place.

So what happens when there is no workpiece to grab on to? Additive manufacturing presents unique challenges that require innovative solutions for part stabilization.

Part Stabilization Fundamentals

Additive manufacturing starts with nothing and progressively builds up material until a part is complete. The build platform is the only available surface for providing support and stability, and the relative location between the part and the platform must remain fixed throughout the build. With geometry that is fully self-supporting (such as a pyramid or cube), the only concern is ensuring adequate adhesion between the part and the build platform.

Self-supporting geometry examples: pyramids and rectangular parts

Understanding Self-Supporting Geometry

Self-supporting geometry means that new material is being deposited on top of, and adhering to, material from the preceding layer throughout the entire build. There is a small allowance for overhang, determined by the material and technology being used. It is technically possible to print a fully self-supporting inverted pyramid if the overhang of each layer is below the technology's minimum threshold.

Anything beyond the maximum overhang is at risk of slumping, which can lead to defects or entire print failures. In aerospace and automotive applications where precision is critical, understanding these limitations is essential for successful part production.

Left: Printer can deposit model and support material Right: Single material for model and support geometry

Support Material Strategies

One way to overcome overhang limitations is to print extra geometry that acts as removable scaffolding. This can add significant labor if you attempt to model supports manually. Fortunately, modern slicing software is capable of automatically generating optimized support structures based on part geometry and technology constraints.

Support can either be made of the same material as the model, or it can be a different material, making it easier to differentiate and remove. Each technology has different solutions for how to support parts. Technologies that use lasers to cure resin or sinter powder, such as SLA, SLS, or DMLS, are typically limited to single-material systems. Machines that deposit material with a print head or extruder, such as FDM or PolyJet, can be designed with multiple nozzles to deposit more than one material.

SLS - The Self-Supporting Advantage

Selective Laser Sintering (SLS) is unique among 3D printing technologies because it doesn't require traditional support structures. Parts are supported by the print medium (powder) itself throughout the entire build process. This fundamental advantage enables several key benefits for production environments.

SLS parts after powder removal showing self-supporting capability

Production Advantages of SLS

Since SLS parts don't require a support footprint that contacts the platform, they can be tightly packed throughout the entire build volume. This enables very high production throughput, making SLS ideal for volume manufacturing applications in automotive and industrial design where multiple parts need to be produced efficiently.

Design Freedom with SLS

The self-supporting nature of SLS enables design possibilities that would be impossible or extremely difficult with other technologies. Complex internal geometries, moving assemblies printed in place, and parts with extreme undercuts are all feasible without the constraints imposed by support structures.

DMLS - Metal Support Engineering

Direct Metal Laser Sintering (DMLS) operates similarly to SLS in that parts are built in a powder bed, but metal supports are required to add stability and prevent movement and warping during the intense thermal processes involved in metal 3D printing. These supports serve multiple critical functions beyond simple geometric support.

Functions of Metal Supports

In DMLS, supports serve several essential purposes:

• Thermal Management: Act as heat sinks to conduct heat away from critical features
• Distortion Prevention: Anchor parts to prevent thermal warping and curling
• Geometric Support: Support overhanging features during the build process
• Powder Removal: Provide access for powder removal from internal cavities

DMLS metal support structures providing thermal management and geometric stability

Supports are printed in the same material as the part, requiring manual or machine removal after printing is complete. This can affect the surface finish of parts, and support removal can be quite difficult in hard-to-access areas, making design optimization crucial for aerospace and medical device applications.

3D printed metal benefits significantly from optimizing geometry for printing. There are many ways to reduce or completely eliminate the need for supports on critical features through intelligent design modifications and part orientation strategies.

SLA - Precision Lattice Supports

Stereolithography (SLA) parts are made by curing liquid photopolymer resin using precisely controlled laser or light sources. The unique properties of liquid resin require carefully engineered support structures to ensure part accuracy and surface quality.

SLA Build Orientations

There are two primary methods for SLA printing, each with distinct support requirements:

Standard SLA: Industrial SLA machines are designed such that the build platform descends into the resin as the part is built. Curing happens at the surface of the resin, and then the platform moves down, submerging the previous layer so that a new layer can be built on top.

Inverted SLA: Desktop machines typically operate with a build platform that is pulled up from a thin layer of resin on top of a transparent membrane through which a laser or projector cures material.

SLA Support Architecture

SLA supports are generated as sophisticated 3D lattice structures, with towers extending up and narrowing to many single touch-points. The position, density, and thickness of these structures is optimized to reduce material use without compromising stability. This precise engineering is particularly important for medical device manufacturing where surface quality and dimensional accuracy are critical.

Industrial SLA 3D printer with precision lattice support architecture

With standard SLA, the part is submerged in viscous resin which contributes significantly to part stability. Supports can be very thin, with small touch-points. Once printed, they can be broken off easily by hand, leaving behind very small breakpoints that can be removed with light sanding.

Inverted SLA requires much thicker supports and larger touch-points to counteract gravity as the part hangs from the build platform. This makes post-processing more difficult and can compromise surface finish quality on supported surfaces.

FDM - Dual Material Solutions

Fused Deposition Modeling (FDM) technology offers unique advantages for support material through dual-extrusion systems. Industrial FDM machines typically feature two print heads: one for model material and another for specialized support material.

FDM dual-material system with breakaway support material

Breakaway Support Systems

Breakaway support material is engineered so that it doesn't chemically bond to the model material, making removal straightforward. Support is printed with controlled infill underneath overhanging areas, providing necessary structural support while remaining easily removable after printing.

This approach is particularly valuable for industrial design prototyping where rapid iteration and minimal post-processing are essential for meeting development timelines.

Soluble Support Materials

For complex parts with internal geometries, we offer soluble support materials compatible with most engineering thermoplastics including ABS, ASA, PC-ABS, ABS-ESD7, Polycarbonate, and Nylon 12. These supports dissolve completely when soaked in specific solutions, enabling production of parts with internal cavities that would be impossible to clear with breakaway supports.

This capability is essential for parts with difficult-to-access internal volumes and is necessary for applications in aerospace where complex internal ducting or cooling channels are required.

PolyJet - Gel Support Innovation

PolyJet technology represents a unique approach to support material through its multi-material inkjet system. The technology uses a print head with multiple nozzles to simultaneously deposit multiple photopolymer resins, which are immediately cured with UV light.

Gel-Like Support Properties

The support material in PolyJet printing is a gel-like substance that can be easily removed after printing, often by simply washing with water or using gentle mechanical removal. This material is specifically formulated to provide adequate support during the build process while remaining easily removable without affecting part surface quality.

This approach enables extremely fine detail and smooth surface finishes, making PolyJet ideal for medical device manufacturing where precision and biocompatibility are essential, and film prop manufacturing where visual detail is paramount.

Multi-Material Capabilities

Beyond support material, PolyJet's multi-material capabilities enable printing parts with varying mechanical properties within a single build. Rigid and flexible materials can be combined, with support material filling any voids or providing temporary structure during the build process.

Design Guidelines for Support Optimization

When designing parts for additive manufacturing, understanding how to minimize support requirements while maximizing part performance is essential. These guidelines apply across all technologies but must be adapted to specific manufacturing processes and material properties.

Self-Supporting Design Principles

Design your parts to be as self-supporting as possible. This means using bevels, fillets, or chamfers to ease abrupt angle changes that would otherwise create overhangs. Generally, smoothing transitions across the whole part provides much more flexibility during build preparation and reduces support material requirements.

Fillets and chamfers can significantly reduce support requirement

A and B Surface Strategy

It's good practice to identify critical and non-critical surfaces so that parts can be oriented accordingly. An A surface is typically the part of a model that comes into contact with the end user, like the outer finished surface of an enclosure, while the B surface tends to be hidden once assembled or installed.

Defining A and B surfaces gives you control over where supports are placed

It's usually best to orient the part with the B surface contacting the support structure. This strategy is particularly important in automotive applications where exterior surface quality is critical for both aesthetics and aerodynamic performance.

Support Accessibility Design

Make sure support removal is possible. Internal volumes that require support may not allow for support to be removed after printing. Support can be left inside if this doesn't affect part function, but if removal is required, consider adjusting the geometry or orientation so that internal volumes are entirely self-supporting.

Alternatively, design removal holes for extracting supports. These access holes can often be incorporated into the part's functional design or placed in non-critical areas where they can be plugged or finished after support removal.

Leveraging Support Advantages

Supports enable geometries and arrangements that would be impossible with traditional manufacturing methods. For example, linked components in an assembly can be printed all together without touching, creating complex mechanical assemblies in a single build.

Interlocked mechanical assembly printed in a single build using support structures

Parts can be nested very tightly for higher volume production since there's no requirement for tool access during the build process. In most cases, internal complexity is a non-issue, enabling design innovations that would be impossible or prohibitively expensive with traditional manufacturing.

Industry-Specific Considerations

Different industries have varying requirements for support strategy optimization:

• Aerospace: Minimize weight while maintaining structural integrity; often requires complex internal geometries
• Medical Devices: Biocompatibility and surface finish critical; support contact must be minimized on patient-contact surfaces
• Automotive: Balance between production speed and surface quality for both functional and aesthetic components
• Architectural Models: Fine detail preservation with minimal post-processing for rapid iteration

Technology-Specific Support Summary

Conclusion

Each additive manufacturing technology has its own sophisticated strategy for part stabilization, and understanding these differences is crucial for successful part design and production. From SLS's self-supporting powder bed to DMLS's engineered metal supports, from SLA's precision lattice structures to FDM's dual-material systems and PolyJet's gel-like supports, each approach offers unique advantages for specific applications.

At Forge Labs, our technicians are expertly equipped to optimize part orientation and support settings for any technology being used. We analyze each project's specific requirements, considering factors such as material properties, geometric constraints, surface quality requirements, and post-processing capabilities to deliver optimal results.

Whether you're developing prototypes for rapid iteration or preparing for volume production, understanding support strategies across different technologies empowers better design decisions and more efficient manufacturing processes. The investment in proper support design and optimization pays dividends in reduced post-processing time, improved surface quality, and enhanced part performance.