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3D printing tips
April 28, 2023
An Introduction to Structural 3D Printing
Flashforge

The phrase 3D printing encompasses many fields with different qualities and applications. Getting to know the basics of 3D printing is easy enough, and it won’t take a beginner that long to figure their way around the technology. However, depending on their interests, beginners may eventually find themselves focusing more on niche areas of 3D printing. One of these niche areas is structural 3D printing.

Although the term has been used to refer to the use of 3D printing in construction, in this case, it refers to a different approach to printing using an FDM or resin printer like the Foto 9.25

What is Structural 3D Printing?

One of the challenges that have persisted in 3D printing is that printing certain items is always more challenging than printing others. If you examine some of the print designs that have challenged you in the past, you’ll realize that many of them will have features such as:

  • Overhangs
  • Vertically oriented holes
  • Bridges
  • Thin sections

All these features have one thing in common, i.e., they have significant sections that receive little to no support from below during printing. This lack of support means that the molten plastic material deposited in these sections is much more likely to be affected by gravity. Regardless of how such prints fail, one of the things you’ll note will be the presence of some drooping.

Structural 3D printing, therefore, refers to the practice of printing these challenging structures while maintaining the overall shape and function of the part being printed.

Why is Structural 3D Printing Important?

If you take a walk outside today, you’ll realize that the features described above are found everywhere. This includes both natural and man-made features. Even you can imitate such a feature just by stretching out your arm or leg. Outside the world of 3D printing, such features are supported in different ways e.g., by bones or steel reinforcements. 

Because of how a 3D printer operates, there is no simple way of providing this support during printing. Unfortunately, it’s not possible to completely avoid having to print these structures. Many of us will include these features in our designs without even intending to. Additionally, because many of the designs printed using 3D printers are copies of objects or structures in the real world, these features will still show up. The best solution, therefore, is to understand what to do to print these features as best as you possibly can. 

Approaches to Structural 3D Printing

There are different approaches to printing challenging structures in 3D printing. Specific FDM 3D printing applications will dictate the best approach in any situation. Some of the approaches that are regularly used include:

  1. Using support structures
  2. Changing print orientation on the print bed
  3. Redesigning the part
  4. Choosing another material

Use of Support Structures

Use of support structures is one of the most common methods used to handle challenging print sections. As the name suggests, a support structure is an additional feature that is printed exclusively to hold up specific sections of the print during printing. Support structures usually do an adequate job when paired with the right 3D printer and 3D printing material. However, they have several key drawbacks. 

3d model in Flashprint slicer with supports

Figure 1: 3D print model sliced with supports

The first drawback is that the print uses more material than it would otherwise need. Support structures serve no purpose after printing and are actually printed in a way that facilitates their easy removal. Thus, this material ends up in the bin immediately after printing is concluded.

The second drawback is that support structures usually leave behind artifacts where they were attached to the print. Ideally, these artifacts should be difficult to notice but this isn’t always the case especially if the support structure is difficult to remove.

Print Bed Orientation

Although it’s not always an option, this is one of the easiest ways of dealing with difficult prints. Changing the orientation of a print on the FDM or resin printer’s bed may eliminate or significantly reduce the sections that need support as shown below.

3D model in Flashprint slicer without supports

Figure 2: Changing orientation of item on print bed eliminates need for supports.

Redesigning the Part

Although it’s not desirable, sometimes the only option is to completely redesign a part to achieve a successful print. This is the more challenging aspect of structural 3D printing because you’ll need to figure out some way of altering the designs of features while still having a part that serves the function you intended. Reducing the sizes of holes, limiting overhang angles to 45°, and increasing the thickness of some sections are some of the options you’ll have. Due to the skill needed to do this, contracting a professional FDM printing service should be considered for very important parts.

Using a Different Material

The challenges mentioned above are more prevalent in certain materials compared to others. For example, printing overhangs using PLA is easier than using polypropylene. If you’re not required to use a specific material, consider using a material that achieves these features more easily.

close up of a roll of filament

Figure 3: Roll of FDM printing filament.

Structural 3D Printing is a Skill

One of the reasons why an FDM printing service is a viable business is because achieving certain types of prints requires some technical skills. Even with an FDM or resin printer, you’ll need to approach some prints with a different perspective if you’re to get the results you’re looking for.