3D scanning and Printing

Assignment

  • Test the design rules for your printer(s)(group project)
  • Design and 3D print an object (small, few cm) that could not be made subtractively
  • 3D scan an object (and optionally print it)

What should be done

  • Described what you learned by testing the 3D printers
  • Shown how you designed and made your object and explained why it could not be made subtractively
  • Scanned an object
  • Outlined problems and how you fixed them
  • Included your design files and ‘hero shot’ photos of the scan and the final object

At the time of writing this documentation, I'm working in a research for the reconstructive surgery department of Cairo University Educational Hospital.

The idea of the research is to investigate the potential of 3D printing in preoperative planning which is referred to as "Physical Preoperative Planning".

Scanning

In this case I used Invisiulus to convert CT scan files (DICOM format) into 3D models and exported it as STL.

Printing

After scanning, I added the model to Makerware and for the sack of this assignment I scaled it down to minimize the time and the amount of material used

In total It took about 15 mins and 4 grams.

After a lot of practice on a lot of cases, I managed to have good results using 3D Slicer(https://www.slicer.org/)and here I will explain how I managed to plan re-constructive surgery for a patient.

The patient is a young female who was a victim of domestic abuse where she sustained multiple fractures in here mandible(jaw).

We wanted to have a 3D model for her mandible so that we can plan how will we place the plates need for fixating the bones.

First I obtained the CD for the patient's CT scan in DICOM format and imported it into Slicer.

I chose the study series I needed which is then got loaded into the view.

By choosing the 'Volume Rendering' panel to quickly view the bones. I chose the CT-Bones preset.

By adjusting the 'Shift' slider I managed to have a good view of the bones

To create a 3D model, we first have to choose the needed voxels. We do this by first choosing the 'Editor' panel and select 'GenericAnatomyColors'

Then by choosing the 'ThersholdEffect' we manage to choose between two threshold values in the greyscale so that we can choose the voxels between these two values

The default label is tissue, we replace this by bone label

We adjust the slider so that we end up only getting the bones of the skull

Then by choosing 'MakeModelEffect' tool we can convert this label to 3D model.

I repeated the steps but using other tools in the editor to create two labels for the segments of the bones (region 0 and region 1) and create 3D models for them.

Then I exported them by saving the files and select only the 3D models needed in STL format.

In Makerware, I placed the models on the platform to prepare them for printing

And then configured printing settings a printed it.

3D Design

To design something that cannot be manufactured substractively, I decided to design a hollow spring-like model.

Started by creating a sketch of the diameter of spring and a line for its path

Then clicked on the the "Coil" tool, chose the profile and path and changed the pitch.

Then created a sketch on the beginning of the coil, created a smaller circle and projected the path from the first sketch.

Afterwards, created a new Coil with a subtract operation.

Then changed to the "3D Printing" environment and exported the STL.

In Makerware, I added the model, scaled it down and exported the x3g file to place it in the printer's SD card.

I thought that I can get away with no-support but it ended up badly.

So, I printed again with supports

Unfortunately, the supports were heavy and the model broke while removing them.

I probably should have used leaky supports and/or made the model larger not scaled down as in this case.

Files