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3D Scanning and Printing AssignmentFor this assignment we took on 3D Scanning and Printing Techniques and devices.
3D ScanningThe assignment implied to scan a 3D object in order to obtain a digital replica of it, mayber editing/improving/mixing it and if possible, print the result in the machine. I attempted two different types of scanning, first using a CREAFORM EXA Scanner brought to the lab and second using 123D Catch Photogrammetry. First, we used the 3D Scanner, the procedure of use not that simple, since it needed a certain expertise to be done, this meaning The scanning had to be supervised.
Due to the complexity of the part, The Scanning had to be made in two separate stages, and the resulting meshes had to be integrated into one.
We had to take into account the degree of reflection or glimmer that would originate from a given piece to be scanned, since the scanner was laser-based and the reflections would not be registered properly, this happened with a lightbulb body we tried to process:
The reflection made impossible for the scanner to get the metalic section (The green circle) The experts recommended us to use an opaquing powder in order to get that part to be properly scanned.
After the scanning process, it was time for the composition/editing process: eliminating excess points and finally, joining both meshes into one, Geomagic was used for this, Still, after the scanning and composing, there were still a few errors to correct.
I used Autodesk Meshmixer in order to correct the remaining errors the model had. The process was easy to follow and straightforward, the holes are marked in blue and the non-manifold edges in red, The software's inspector tool solved things in a very practical manner, however the detail of the upper part (aqua circle) was not as smooth as the original part, not much to do about it.
Afterwards, the model was nearly ready for printing. For the second case I used Autodesk 123D catch in order to create a mesh model out of a series of photos I took of the sculpture of Prof. Valdez, an Emeritus Professor in ESAN University.
44 Photos of the sculpture were taken in order to generate the 3d model, The accuracy was not perfect in detail, and since I could not get to take in the photos the full detail of the upper head of the sculpture (just a little too high) the resulting mesh was not good at all there.
One of the surprising facts about Autodesk 123D Catch was the amount of environmental data it gets into the model in addition to the object of interest. At a glance, the sculpture scan is in the red mark in the photo below:
So, a lot of mesh cleaning was in order to actually get a model worth printing, removing the additional meshes was time-consuming and not entirely clean, meaning you have to be careful about what you delete before pressing the delete button, but, the model, eventually, was as clean as It could be, to save space I composed the process in a single picture: (i) The "clean" Model, (ii) a plane-cut to make it fit for printing and (iii) the model "ready to print".
And the detail of the top head part, when the photocomposition did not get it right:
I tried to get this fixed in Meshmixer,but without success. As I edited in Meshmixer, I inadvertenly made the mesh solid, which would cost me later, in the Printing Stage:
Finally, I gave the Kinect in the Lab a go, using OpenKinect, I tried to Scan Myself with it, since it works better with bigger objects and did not bring anything to scan. The results were not as great since the software in Trial Mode limits the capture to 5000 polygons, still, it needs quite a lot of work if I'm going to print it.
I tried to repair it using Meshmixer, but to no avail... still waiting for the program to respond.
However netfabb Basic worked just fine:
After that, te mesh was nearly printing-ready.
3D PrintingFor the Printing section I used two 3D Printers available: The Makerbot Replicator 2X available at TECSUP and the Felix 2.0 we have at ESAN University, for comparison purposes, I used the model for the Professor for printing.
First, I was not completely familiar with the intricacies of the Felix Printer inner workings, so the setting up processor was not as easy-going, and some things needed to be considered in order to get the printing done. I actually got the model to print properly at the fourth attempt. First, I opened the STL file generated by 123D Catch in the Felix Printer Software (Felix Repetier - Host) and choose the printer settings before slicing the model and generating the G-code for the printing. First, the STL as the Software read it.
Before setting it up for printing, as for the settings, I only added the raft for printing and used standard quality settings, after this, the Software created the G code for the machine.
Printing was a very different matter, as already mentioned, it took four attempts to get the printer to behave properly, after some trial and error, including the PLA getting stuck on the extruder (below) or the raft not bonding to the platform and being torn by the extruder's support piece (below that)
I realized the printing tray was not properly leveled, so I decided to move it to the right and It Worked. It took quite a while, since the STL was solid instead of hollow. Finally, It was done:
Printing in the Makerbot was a lot simpler, The Makerware app is very friendly and the parameters configuration quite straightforward, the printing parameters were: layer height: 0.25 mm, shells: 4, infill: 10%, speed: 100
I got the printer to finish in the second attempt, in the first, the Printer LED panel displayed "INVALID CODE: if this is the first time you print this model, try again" Which I did, and this time it came out right. In the picture the difference can be seen:
The slicer it seems, tried to build for the details in the front of the sculpture, no sucess, sometimes a better printer will not print it better. Still, as every 3D printer, the Makerbot comes with its own challenges, here is a comparative view of both prints:
I did print the first scanned piece in the Makerbot, here, the trick was positioning, since the mesh was tilted and tricky to set upon the platform in the software, it was mostly trial and error, in the images below can be seen, left, the original positioning of the part, middle, rotating it to get it to the platform and right, done! (or so it seemed)
When I started Printing it became obvious that the model was still slightly tilted, and the first attempt failed. I added an additional support in the second attempt to compensate, and finally, it was done, The printing prameters were the same as the Professor Model.
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