Lulzbot has incredible tolerances on their machines. Honestly in my opinion the 3 main problems that can cause a part to change its dimensions are
thermal contraction, warping and the “elephant foot”. These 3 phenomena are present on any price range of FMD (Fused Deposition Modeling) 3D printers.
Many variables play a role that could directly affect the severity of these phenomena. More variables could play a role negatively if you don’t have a
controlled area around the printer. In my case I don’t have a proper Lab to place my printer. My printer is living in my living room.
To check the tolerances, I decided to make my one little test board. LulzBot’s Documentation
is amazing to verify first party specs. They even have calibration parameter to have the appropriate tolerances. The appropriate range is ±.250mm. I’m definitely in the rang. The only
paramter I would change would be to dial down a little the Z-Offset to improve the measurement.
Individual Assignments
Week 5
My favorite CAD software is Solidworks and then Onshape.
Due to a lack of resources in Honduras most of my things tend to have DIY nature. After getting my CNC I needed tubing for
my dust collection system. I have little to work with so I decided to see what tubing I could find and 3D print the adapters.
The flexible tube I planned to use had approximately a 10cm. diameter. The diameter was going to be a big problem because I
couldn’t make a normal adapter. The adapter would never fit because it to close to the router of my CNC. I decided to make
the adapter with a 60° angle. This would solve the problem but easier said then don.
I hate making models that require supports so I normally design using my 3D printer’s capabilities to the maximum. Normally if
I need supports y try to design my own.
There is no doubt in my mind this is the hardest part I’ve ever had to design. This adapter appears to be harmless
but that’s fare from true. After getting the proper measurements with some calipers I started modeling with the proper tolerance.
I was sure I was going to use a Loft in Solidworks to make the final shape. The hard part was to set the model in a way that the Loft
would make the shape. I tried different methods but none of them was properly working with the Loft. I tried revolve and add new planes.
Revolve took too much time and adding the planes for some reason added a bump on a part it meant to be straight.
After a couple of days trying different methods, I came with a different approach. I made a sketch that represented a sagittal
plan cut of the adapter. This gave me the parametric outline of what I needed to make. The problematic part was placing the
top cylinder on a specific coordinate on the 3D cartesian plane. Sketching on a normal 2D plane made it really complicated,
but with a 3D sketch I don’t have any kind of restriction to place a sketch on a specific coordinate. Using the parametric
sagittal plan cut works as the constrains to place the cylinder on top. By doing this I was able to create the best rout for
the Loft to follow. Then make a 4mm shell and rounded all sharp areas.
Now is time to setup the 3D printer’s Slicer parameters and print!
I only had 1 imperfection not related to the 3D printer’s capabilities nor the filament (Visible on the "Vacuum Adapter" Pic.).
I was so angry that I didn’t completely forgot to take pictures. The nozzle got clogged really bad with only remaining 30 min. to
finish the print. My 3D printer is located I the middle of my living room. I don’t have any kind of climatization system to have more
control over the temperature in my house. It’s important to mention that Honduras sometimes has crazy weather shifts (morning 15°C, noon 27°C or >).
Taking all of this to account I made the hypothesis that the temperature in my house was too high when the clogging happened. With a temperature
gun I started measuring temperatures around noon. I was shocked when I saw that the temperature of my roof was higher than the 3D printer’s bed
(Bed Temp = 52°C). This means that the air around the nozzle was probable higher o equal to the thermal sink on the nozzle. After I determined
this, I’ll never print at noon again unless we are at cold season. Since then, I’ve never had any kind of clogging problems.
I tried to use an Xbox 360 Kinect as a 3D scanner.
This is great, because you could by one used at a lower price (it works with newer versions of Kinect).
I used a tutorial in YouTube to try to setup the best environment to generate the best quality scan I could.
Setting up this environment is problematic, because the quality of the scan depends a lot on the light around the scanned object.
The black spot on my nose is the shadow that the roof lights created on my face (this can be fixed by adding more lights or playing around with the angles of the light.)
The methodology to create the 3D scan s by taking pictures and rotating the object of your selection. The number
of pictures taken will determine the quality of the scan (more pictures = better quality of scanned object).
