6. 3D Scanning and printing¶
All this information is referred to 3D Scanning and printing class.
- Design and 3D print an object (small, few cm3, limited by printer time) that could not be made subtractive.
- 3D scan an object (and optionally print it).
- Test the design rules for your 3D printer(s)
Cura is an open source 3D printer slicing application. It was created by David Braam who was later employed by Ultimaker, a 3D printer manufacturing company, to maintain the software.
Cura has 2 versions to modify the key parameters that would define your 3D print. It has its recommended version with little key parameters as:
- Filament type.
- Layer height
- Build plate adhesion
You can customize the parameters you will like to modify as you adquire more knowledge about 3D printing.
Formlabs Form 2¶
- N° layers
- Type material
- Geometry Resolution
- Scan Volume
The first part I 3D printed was the extruder base, this is part of my final project. It purpose is to join with a brass anti backlash nut, so the tank where the viscous fluid will be stored can extrude.
As this is a test part, I prioritized its printing time over its quality. So the parameters I entered to the software are:
|Support - Lines||10||%|
There are 2 key options on Cura that I liked a lot:
Allows the user to inspect how the model is going to be built through the 3D printing process:
In the image we can see:
1.- Key: Each part of the layer has an specific color that allows the user to distinguish to wich parameter it is related. This way it is easier to modify in case you want to change your parts properties.
2.- The part: Here with the same color code we can distinguish between the infill, the shels, the helpers, even see the machines travels.
3.- It allows as to know which layer of the process ate we looking at.
I think this is a really strong feature that not every 3D printing software includes, because it allows the user to search for possible mistakes in the gcode before it is send to print.
A key disadvantage in rapid prototyping of 3D printers is it time to get the part finished. Cura allows the user to see a desegregated time specification that allows the user to know the percentage of time taken by each part of the process.
This is really helpful when you want to lower the printing time. You can change the specific parameters that are adding more time to your 3D printing process.
Additive v/s Substractive¶
To fabricate something through a substractive process, using a 3 axis machine, all cuts have to be in the same plane; to change planes in the milling tool you’ll have to have a fourth or sometimes a fifth axis. As you can see in the 3D model I printed the part has holes in the XY, YZ and XZ axis.
In order to do more complex geometries, additive manufacture is more propper in prototyping fase, because it has the posibility to develope more complex geometries.
This 3D model followed the assignment rule to build something that couldn’t been built in a subtractive way. It is composed by a ring that has 3 more rings in its inside.
To send a 3D model to print in a form 2, it has to be defined as “printable” for the software, this implies a correct support.
This process is mostly done by the software, the user just clicks the magic wand and it would acomodate automatically the model into is correct position.
After the 3D printing is finished, the result has to be cleaned in the “Formwash” a machine that gives an alcohol wash to the 3D model, to remove the extra resin it can have.
Finally, it has to be cured in the Form Cure oven
I didn’t worked, because the ovals extrusion radius is too big so the 2 parts interfere each other. As you can see in the model, this shouldn’t happened, so we can analyses the problems with the machines resolution.
3D scanning is a hard process that needs a lot of concentration.
You have to do a complete 360° degrees scan of the part you want to get into the software. Then it comes the post-processing process, were you edit he resulting scan to get rid of the “noise”:
The key steps in the post-process are:
1.- Solidify: It fills the holes you couldn’t scan properly in the scanning process.
2.- Trim: Allows the user to cut points that the scanner could get as part of the piece, but aren’t really from it.