## 17 April 2020

### RESEARCH: SolidWorks Topology Optimization

One of the things I have come to realise with my AR2 project is that having a multi-extrusion 3D printer would be crazy useful, as all my prints to date needed support material which unfortunately is a pain to remove. However, with a multi-extrusion printer you can do fancy stuff like print all supports in PVA, which dissolves in water!

UPDATE: Not with a single hotend ;^)

Hence, I finally bit the bullet (bad time to be spending due to COVID19...) and ordered the MMU2S upgrade for my Prusa i3 MK3S. But there is a small hurdle, the MMU2S is designed for large (and preferably flat) working areas, something I do not have. So I decided to modify my current work space with a shelf to hold the 5 rolls of filament, and to spice things up I tried using the Topology Optimization feature in SolidWorks to design the shelf brackets. Overall, this produced quite an organic shape that reduced the bracket weight and gave it the best stiffness to weight ratio

## The Steps

NOTE 1: I am running SolidWorks 2018 SP5
NOTE 2: Here is an easy to follow tutorial on Topology Optimization in SolidWorks

1. Make a 3D model as you normally would
3. Create a new Topology Study (Simulation → New Study → Topology Study)
4. Select body material (I went with PET as I will be printing in PETG)
5. Define the fixtures (faces where the body will be held in place)
6. Add a force as well as it's direction (I went with 50N as at most the shelf will hold 5 1kg rolls of filament)
7. Add a model goal (I wanted to reduce mass by 40% while having best stiffness to weight ratio)
8. Specify the preserved regions and depth (I selected the bracket mounting faces and went with a depth of 2.5mm)
9. Specify De-mold direction (arrow should be pointing towards flat surface)
10. Create a model mesh (I used a 2mm curvature-based mesh)
11. Run the simulation
12. Finally, adjust the target Material Mass and calculate the Smoothed Mesh

## The Results

• Original model:
• 74.4g
• 210851mm³
• Topology Optimized model:
• 44.5g
• 84013mm³