3D scanning and printing

Group assignments

For this week's mission we will draw a 3D object and print it with a 3D printer. But before that we will
  • Testing the design rules of the 3D printer as a group project.
  • Print an object in 3D.
  • Scan an object in 3D and print it.

3D Printer

3D printing is a so-called additive manufacturing technique which proceeds by adding material, unlike techniques proceeding by removing material such as machining. The principle remains close to that of a classic 2D printer but with a big difference such as: the stacking of layers which creates the volume.
We have two 3D printer types namely formlabs and Sindoh within our FABLAB.
To be able to print a 3D object, we need software that will allow us to model the object in 3D. Parmi les logiciels de modélisation 3D on peut citer:
  • AutoCAD;
  • Blender;
  • SketchUP;
  • SolidWorks, etc.

Safety and Precautions

3D Printers require maintenance to keep them in good condition. Before starting the prints we will first perform preventive maintenance.As preventive maintenance we will:
  • Check our nozzle and thermal barrier;
  • Check the condition of the extruder;
  • Check the belt tension;
  • Check 3D printer screws;
  • Store the filament in an appropriate place;
  • Check the amount of filament remaining;
  • and finally, thoroughly clean our 3D printer.

Sindoh

Testing the design rules of the 3D printer in our lab

For this mission, we used several methods which led to several different results.

Characteristics

FFF (Fused Filament Fabrication) printing technology
Print head: Individual nozzle
Nozzle diameter: 0.4mm
Max size construction (WxDxH): 210 x 200 x 195 mm
Sindoh Filament Material: PLA, ABS, etc.
Connectivity: USB 2.0 Key / 2.0 Host, Ethernet (1G), Wi-Fi
Layer Thickness: 0.05~0.40mm
Filament diameter: 1.75mm
Size (WxDxH): 421 × 433 × 439mm (16.5”x17”x17.2”)
User Interface 5-chip color touch screen
Leveling Automatic leveling measurement + Manual adjustment
Auto-loading cartridge: Automatic loading of filament at the nozzle
3DWOX Desktop Slicer
User Interface 5-chip color touch screen
To start the various tests we drew 3D objects on solidworks and converted to STL format to be able to print them. To do this we will start solidworks.
We have focused our various tests on three aspects, namely the printing angle, the junction clearance and the bridges. To do this we used two techniques, with support and without support.

Printing with Support

To be able to print our 3D object we will first slice it. In other words, the slicer divides the object into a stack of layers (it slices the object) and tells the printer what the extruder or laser should do. We will use 3DWOX Desktop Slicer to make our different slices.
The best layer height with 3DWOX1 is 0.05mm. For this object we end up with 35h14mn as printing time.So we decided to test 0.20mm which is the average to see what it will give. And as printing time we went from 35h14mn to 11h11mn.
3DWOX1 settings
Sliced object at 0.2mm
After printing, we noticed through some measurements that the object was not accurate. There is a difference of 0.03mm on average. In addition, we have found that the minimum clearance is 0.3 mm. Less than that, the piece does not move and is attached to the bar.
Object with support
Object without support

Printing without support

In this part of our work we have made 3D prints without support. The objective here is to see the limits of our printer in the face of different printing without support.
For this, we will performed the following tests:
  • bridge tests;
  • angular tests;
  • and tests on the accuracy of printed objects.
1. Bridge
The purpose of this exercise is to see how the printer will behave between the bridges.We used 0.2mm slice for this test.
Sliced object at 0.2mm (without support)
The bridging pattern didn't go over very well. We did not get the results we hoped for.We noticed that the sag at the deck increases with the length of the object.
Bridge test
2. Angle
Here we wanted to test the printing angle. We used the same trache value as the previous test. We have noticed that the angle is only accurate at 130. And becomes bad from 120.
On our image we see that the angle is no longer accurate to 100 degre.
Angle test (Inaccurate angle at 100 degree)
3. Precision
For this task we wanted to test the precision and printing tolerance of our printer.Thus, we carried out several tests with different measurements. We started with a 0.2mm print as the layer writer. After printing, it was found that prints smaller than 0.5mm were not printed and holes were visible from 0.2mm. Nevertheless, the results were accurate from 0.8 mm.
The circled part on our image represents the space of unprinted objects. These objects have a thickness between 0.1 and 0.5mm.
0.2mm slice
Accurate measurement to 0.82mm
We continued with 0.4mm and 0.05mm tests.But we did not get the expected results because there are no big differences with the previous results. However, we noticed a slight difference with the 0.05mm print as the print was a bit more accurate from 0.6mm.
0.05 mm slice
Accurate measurement to 0.64mm

Formlabs 3

In this part of our work, we will continue the tests with our second printer, namely formlabs3.
The Form 3 is an industrial resin 3D printer and it uses Prefrom as a slicer.

Characteristics

Maximum precision: 25 microns (0.025 mm/layer).
Dimensions of the printing layer: 145x145x185mm.
Compatible materials Formlabs Resins.
LFS (Low Force Stereolithography) technology.
Advanced Z resolution: 25 to 300 micron.
Advanced 25 micron XY resolution.
Laser spot size 82 microns.
Software: Pre-form version.
Files supported: .stl, .obj.
Spécifications Laser: Class 1 Laser Product.
For the test, we used a layer thickness of 0.05 mm with a time of 8h.
This image represents our configuration on Preform. We have the printing time, the type of material used circled in red and the blue arrow to indicate the automatic generation of the support.
Preform settings
Once the object was printed, we noticed that even 0.3mm objects were visible and the object was smooth.In addition to being smooth, the measurements were very precise.However below 0.3mm the cuts were not very visible.
In this image we could see the missing objects on our previous tests.
0.05 mm with formlabs
Accurate measurement to 0.34mm
This represents our impression with more accurate measurements.
Final objects

Comparison

During our work we noticed some difference between the printers. Its differences are among other things the performance and the print quality of each printer.We will therefore illustrate this in the table below.
Printing time Print quality Settings
Both printers have a great print time. When we take an object with the same size and layer height like 0.05mm, we can see that the print time difference is about 10 hours or even more. Formlabs takes much longer than the Sindoh 3DWOX1. Regarding the quality of printing formlabs is more precise in measurements and smoother. Regarding the layer height on 3DWOX1 we can choose the thickness according to our needs while the parameters on formlabs are prefinished and we can only use 0.05mm.

Individual assignments

In this part of our work, I used different printers with different settings to be able to obtain the desired result. But as we said at the beginning of our work, to model the objects we have two methods. The process of additive manufacturing which produces objects by adding material layer by layer (the process used by 3D printers) and subtractive manufacturing which removes material from a solid form to create parts (this process is used by CNC machines).
We will always use printers because it would be difficult to use subtractive manufacturing to be able to obtain our object. We will still be using printers as it would be difficult to use subtractive manufacturing to be able to get our design, since our design has hidden corners and the objects are also overlapped.
To start I used solidworks to draw the model of the desired object.
The object is a roundabout in the city of Ouagadougou. I wanted to draw it because Ouagadougou being the capital of African cinema, it represents the cinematographic culture not only of Burkina Faso but also of all of Africa.
Solidworks design
3DWOX1 settings with 0.05mm slice
Printed object with support
After this disappointment I therefore decided to make another impression but this time I played on the printing layer and the removal of the support.This allowed me to reduce the printing time but the result turned out to be worse than the first experience.
Printed object without support
In reality I did not obtain satisfactory results with Sindoh 3DWOX1.So I decided to continue the adventure with formlabs for see.
For thhis I used support and 0.05mm as print layer.
With formlabs, I got what I wanted and above all the precision of the measurements was satisfactory.

Final 3D object

All printed objects

3D Scanning

In this part of our work, we use a scanner to digitize an object and obtain it in 3D. As this is my first time using a 3D scanner, I was really looking forward to using it.
As 3D scanner in our FABLAB, we have XYZprinting product.
Before starting the scan, we installed the software that will send us the image of the scanned object. As software, we used XYZscan Handy which is the software supplied with the scanner.
With our scanner, it was not only difficult to scan a small object but it also did not take black colors into account.
To remedy this problem we used a white powder on the object to make it more white. Additionally, we've dropped a black cover underneath to let the object show through.

Encountered difficulties

During the work, we encountered several difficulties.
We had one out of three Sindoh printers working normally.Given the printing times of the printers, we could not work with a single printer.So we decided to restore both printers to good condition.
After diagnosis, we found two problems on Sindoh printers, namely:
  • nozzle clogging;
  • and filament intersection clogging.

    • 1. Nozzle repair

    For the repair, we proceeded to disassemble the nozzle to be able to remove the clogged filament. This operation allowed us to recover a printer.

    2. Filament intersection point input

    Once the printer was running we noticed that the motor turns for a moment and after a while we hear the noise of the gears and the filament does not come out And the machine pops out this error."Remove the cartridge. Check if there is any filament left in the tube or at the entrance to the filament insertion point"
    So we thought that for the error the intersection point of the filament was clogged. And for noise, the gears weren't well meshed or they lacked lubrication.After dismantling we noticed that the sprockets were not well meshed and we greased the pins a little. However, the entrance to the point of intersection of the filaments was not blocked.
    Printer disassembled
    Faulty part (the entrance to the point of intersection of the filaments)
    Once reassembled the error continued to appear but we no longer heard the noise of the gears.So we started testing with the two imprimantes Sindoh.

    3. Cleaning machin

    It is a machine that cleans objects printed with formlabs.She uses alcohol for cleaning.During our test, we found that all the alcohol had evaporated and the resin remained stuck inside. We had to do the complete cleaning of the machine with alcohol in order to use it.
    On our image above, the circled part represents the resin stuck inside the machine
    Cleaning machine
    Colgged object