3D scanning and printing

A Precision/Orverhang test was performed on a Ultimaker3 3D printer and Cura slicer. The settings used are using are the preset standard settings for a normal quality print with PLA filament. Mainly:

• Layer height: 0.15mm
• Wall thickness: 1mm
• Infill Density: 20%
• Print temperature: 200degC
• Build plate: 60 degC
• Print speed> 80mm/s
• Printing temperature:200degC
• Support: Non
• Build pate adhesion type> none

For The Precision/Orverhang test we downloaded a small test file from thingiverse. It just took 40 min to print and gave very decent result

• Hole size (3 holes 3/4/5mm):Good precision
• Nut size (M4 Nut should fit perfectly): It takes a hard push to fit
• Fine details (pyramide, cone, all numbers): Good
• Rounded print (wave, half sphere): Good
• Minimum distance and walls (0.1/0.2/0.3/0.4/0.5/0.6/0.7mm): Only 0.7 and 0.6 are fully separated
• Overhang (25°/30°/35°/40°/45°): Pass
• Bridge print (2/4/8/16/mm): Pass
• Surface (all the flat parts): Good

A Tolerance/Precision test was performed on the Ultimaker3 Extended 3D printer and Cura slicer. We downloaded the Tolerance/Precision test file from thingiverse. The settings used are as for the previous test with PLA filament. The test features moving hinges of varying tolerances ranging from 0.38mm up to 0.635mm. It also features thin walls and wells ranging down to 0.016mm

• Thin walls and wells: Clean
• Range of curvature: Good
• Sloping surfaces to test z-axis resolution: Good
• sharp peak: Very Shapr
• cavity: Clean
• moving hinges of varying tolerances: All were stuck

I'm sceptical about the results of the tolerance test. I've used a different tolerance test for the Flashforge 3D printer (next paragraph) and the clearance was ok for 0.4 and 0.5mm. This could be a design issue. I'm not sure the design of this test is not proper for tolerance. So I would say the tolerance test was inconclusive.

We performed Precision/Ovwehang and a tolerance test on a Flashforge Adventurer3. This machine has a dedicated slicer called Flashprint. We also used PLA.

In this case we tested the print on the High quality preset setting, because the standard settings gave poor results for a part I had previously tried. The settings are mainly:

• Layer height: 0.12mm
• Shell count: 3
• Print speed: 40mm/s
• Infill Density (hexagon pattern): 15%
• Printing/Platform temperature: 210degC / 50degC
• Support: none
• Raft: none

• Hole size (3 holes 3/4/5mm):Moderate precision
• Nut size (M4 Nut should fit perfectly): It takes a hard push to fit
• Fine details (pyramide, cone, all numbers): Small defaults (requiers cleaning)
• Rounded print (wave, half sphere): Small defaults (requiers cleaning)
• Minimum distance and walls (0.1/0.2/0.3/0.4/0.5/0.6/0.7mm): Only 0.7/0.6/0.5 are fully separated
• Overhang (25°/30°/35°/40°/45°): Pass
• Bridge print (2/4/8/16/mm): For 16mm Small defaults (requiers cleaning)
• Surface (all the flat parts): Good

NB: Apparently the Ultimaker gives better results in precision even in normal quality. For tolerance we would have to make the same tolerance test with the Ultimaker to draw conclusions.

For The tolerance test we downloaded another test file from thingiverse. It We tested the print on the standard quality preset setting with PLA filament. The print test tolerance for 0.1/0.15/0.2/0.25/0.3/0.4/0.5mm. The settings are mainly:

• Layer height: 0.18mm
• Shell count: 3
• Print speed: 60mm/s
• Infill Density (hexagon pattern): 15%
• Printing/Platform temperature: 210degC / 50degC
• Support: none
• Raft: none

I first printed this model with the Adventurer3 in red PLA material and high quality settings (same as the settings tested in the precision/oerhang test). No support was needed, nor raft or brim.The Fusion drawing includes parameters to modifies the number of modes, the shape of the torus, its dimensions and the thickness of the wall. To generate the STL file on Fusion you just need to right-click on the name of the drawing (or component) that includes all the bodies to be printed, and select save as STL. Initially, I set the torus diameter at 50mm and the thickness at 1mm, but the STL file was to big and the printing time too long so I scaled it 70% on the slicer to reduce the printing time to 3 hours. So the walls printed were about 0.7mm and the torus diameter 35mm. It can be scaled down to 50% as I have tried to reduce the printing time to 1 hour but the quality of the result is poorer.

I also printed the Villarceau circles with the Form 3 SLA 3D printer in clear V4 resin. The SLA (Stereolithography) technology is very different from the FDM technology used in the previous print. SLA 3D printers use a light source to trace the model on a liquid bed of resin. The part is printed upside down on the build platform. The dedicated slicer software for this 3D printer is Preform. The model was scaled down to 60% on the printer the slicer to bring printing time to 3 hours. The model had to be placed in an oblique position in the slicer to make the file printable, other wise the slicer signals the areas that are not printable by colouring them in red. Support was generated automatically by clicking the support button on the left of the screen. Then additional support was added manually around the week areas highlighted in red. This is done by clicking the edit button in the support window, and then placing vertices on the model on the spots below wich a support structure should be added. After printing post processing is needed to clean the part in a rubbing alcohol solution. The Preform file is available here

1. Create a stl file in a 3D CAD
2. Open the stl file in PREFORM slicer
   (file menu> open)
3. Select resin type
   (bottom bar> print settings> Material> Version)
4. Adjust scale according to printing time
   (tool bar>size> scale)
5. Adjust orientation to minimize sensitive areas (in red) to make the model printable
   (tool bar> orientation)
6. Automaticaly generate support
   (tool bar>support> generate)
7. Manualy adjust support to minimize sensitive areas
   (tool bar>support>edit)
8. Load the selected resin tank in the 3D printer and start the machine
9. Connect the computer and start the print
   (file menu> print> upload job)
10. After printing remove object and place in cleaning solution
11. Manualy remove the support element from model

We used the "Scan In a Box" 3D scanner which has a dedicated software called IDEA. This scanner uses the optical triangulation concept with a laser light source and two cameras. The object I scanned is a plastic puppy I printed on the Falshforge 3D printer. I downloaded the design from Thingiverse. The 3D scanner construct 3D surfaces from the data collected by the two cameras, and the software allows to patch the different 3D images to construct a 3D file which reproduces the shape we've scanned. You need to take many shots of an object in different orientations to reproduce the full object. The steps to do this are:

1. Place the object on a black backgroud
2. Open the software and turn on the camera
3. Click 3D scan to capture the 1st 3D image
4. Slightly change the orientation of the object and scan again
5. Repeate this operation until the object has been fully revolved
6. After revolving the object around one axis, revolve it around another axis
7. With all the 3D images collected you can start constructing the 3D object
8. At this point you wanna save the project
9. In the top toolbar click Activate manual alignment
10. The scanned images are now in two lists (fixed and floating) and there are three windows: for the fixed image, the floating image, and the combined image.
11. Select the first 3D image in the fixed list in the alignment set
12. Select the second 3D image in the floating list in the alignment set
13. Select 3 point on the fixed 3D image
14. Select 3 point on the floating 3D image in the vicinity of the points previously selected
15. In the third window the two images will be superposed according to the points selected
16. If the superposition is close enough click align
17. If the superposition is a match click next and select the next image in the floating object list
18. After completing this process the 3D object should be fully built
19. If it is not, click ok, save, and take more scans targeting the missing areas
20. Activate manual alignment again
21. In the fixed objects list select all the object previously aligned
22. In the floating object list select the new scans not yet aligned an align them one by one
23. Once this process is completed and the object is fully built, create mesh by clicking the pyramid symbol
24. Fix the imperfections using the processing tools to fill holes and smooth the surface