Exporting for 3D Printing

1. The Language of 3D Printing: STL vs. 3MF

When you design in Fusion 360, you're working with "solid" CAD data—perfect mathematical descriptions of curves and surfaces. A 3D printer, however, can't read this directly. It needs a "mesh" file, which is an approximation of your model made up of many small triangles (or polygons).

The two most common mesh file formats are STL and 3MF.

• STL (Stereolithography): The original, decades-old standard. It's universally compatible but only contains the raw geometric shape of the model.
• 3MF (3D Manufacturing Format): A modern format designed to replace STL. It's a "smart" container that can hold not only the geometry but also colors, materials, assembly information, and even slicer settings.

To get a clear understanding of why 3MF is the superior choice for modern 3D printing, especially with a multi-material system like the Bambu AMS, please read the following article.

Key takeaway: For your projects, especially any involving multiple colors or parts with your planned Bambu A1 with AMS, 3MF is the strongly recommended format. It's more efficient, carries more information, and results in smaller, more reliable files.

2. Exporting Models from Fusion 360

Fusion 360 offers several ways to export your components as mesh files. The most common and useful methods are accessed through the "Save as Mesh" command or the "3D Print" utility.

The official Autodesk Fusion channel has a concise video that covers these methods thoroughly. We'll watch it in segments.

The Core Export Process

First, let's look at the basic export dialog and its most important settings. You can access this by right-clicking a component in the Browser tree and selecting "Save as Mesh."

This action opens the Save as Mesh dialog, which is where you'll define the quality of your exported file.

The Refinement setting is crucial for parts with curves. A 'Low' refinement will make a cylinder look faceted, while a 'High' refinement will produce a much smoother surface. For most functional parts you'll design, High is a good starting point.

A Streamlined Workflow: Sending Directly to the Slicer

Instead of saving a file to your computer and then manually opening it in your slicer software (like Bambu Studio), you can send it directly from Fusion 360. This is incredibly efficient, especially when you're iterating on a design.

For a second look at this specific workflow, the following short video is an excellent, focused demonstration.

Handling Assemblies and Multi-Part Exports

What if you want to export all the 3D printed parts for your desk at once? Or what about a single component that's designed with multiple bodies for multi-color printing? The export utility handles this as well.

When exporting for your Bambu A1, you have two powerful options:

1. Exporting an assembly with 'One Body Per File': This will generate separate 3MF/STL files for each component, which you can then arrange on the build plate in Bambu Studio for a large print job.
2. Exporting a multi-body component as a single 3MF file: If you've designed a single part with multiple bodies for different colors, exporting it as one 3MF file allows Bambu Studio to recognize those separate bodies. You can then assign different filaments to each one to be printed with the AMS.

3. Practical Application & Course Conclusion

Let's put this into practice with a quick exercise using your capstone project.

Exercise (10 minutes):

1. Open your capstone desk project file in Fusion 360.
2. In the Browser tree, locate one of the simple 3D printed accessories you designed (for example, the headset mount or a cable clip from Module 11).
3. Export as STL: Right-click the component and select Save as Mesh. In the dialog:
   • Set Format to STL (Binary).
   • Set Unit Type to Millimeter.
   • Set Refinement to High.
   • Click OK and save the file to your computer.
4. Export as 3MF: Repeat the process for the same component, but this time set the Format to 3MF.
5. Compare: Navigate to where you saved the files. Notice the difference in file size between the STL and 3MF versions. The 3MF file is typically smaller and more efficient.
6. (Optional): If you already have Bambu Studio installed, try the "Send to 3D Print Utility" option to send the component directly and see it appear on the virtual build plate.

Congratulations!

You have now completed the entire "Mechanical Design for 3D Printing and DIY" course. Take a moment to reflect on your journey: you started with no CAD experience and have progressed through installing Fusion 360, mastering 2D sketching, creating robust 3D models, designing complex parametric assemblies, and finally, producing a complete set of manufacturing and assembly documents for a significant capstone project.

Key Takeaways from this Lesson:

• The 3MF format is modern, efficient, and superior to STL for nearly all 3D printing applications.
• Use the Save as Mesh or 3D Print utilities in Fusion 360 to export your models.
• Always check your Unit Type (mm) and Refinement settings before exporting.
• Leverage the direct-to-slicer workflow to speed up design iteration.
• Use the 'One Body Per File' option to export all parts of an assembly at once.

You now possess the foundational skill set to confidently pursue your goals. Whether it's designing and printing a custom gaming accessory this weekend, reverse-engineering a broken part for a household repair, or beginning the fabrication of your custom PC desk, you have the knowledge to turn your ideas into reality.

The learning process never truly ends, but your formal instruction in this course is complete. Well done, and I wish you the best of luck with all your future projects.