5. 3D Scanning and Printing¶

This week focused on the processes involved in 3D scanning and printing. I once again teamed up with Anna, Kerstin and Lars, the other students from HRW FabLab, to characterize our lab’s printers’ capabilities. You can find our group work page right here.

Based on the things we found out I designed and printed some things that can only be manufactured additively. To finish this week I also used one of our 3D scanners to compare an object to its scanned and printed counterpart.

Some key takeaways from the group assignment are that while the differences in modern 3D printers’ performance are quite small, they are definitely still there. For instance the Bambu Lab X1 Carbon has produced the best overhangs while the Prusa Mk4 showed the highest dimensional accuracy. Of course all of this can vary based on the material that is used, but we’d have to do more tests to see how much of a difference it actually makes. What surprised me the most was the performance of the Bambu Lab A1 mini. With a price of 200€ this printer has no business being this good. I guess the days of cheap clones spontaneously combusting, having terrible bed adhesion or clogging the nozzle after 2 minutes of printing can finally be over.

Designing and printing a FabLab coin¶

The humble FabLab coin was one of the first things I was tasked to design and print when I started working at HRW FabLab in 2021. To this day we give them away to visitors, at conventions and other events.
Let me tell you, once you have held one of these in your hands and let it spin a couple of times you start to understand why there once was such a hype around fidget spinners.
And the best thing about it? No assembly required.

Here is a quick rundown of how I designed it:

I started by drawing three concentric circles, one for the spinning coin and two for the outer ring

then I went to the top of the circles to draw a kind of thorn shape that is going to be the hinge and indentation that will enable the whole thing to spin
I used concentric fillets on the thorn’s corners and mirrored it to the other side

next I finished the sketch and started an Extrude command where I selected both the inner coin and the outer ring and gave everything a thickness of 5mm

I headed to the CREATE menu and started a Revolve command
little thing about Revolve commands: you need to only select one half of the thorn’s profile, otherwise the created body or cut would intersect itself and Fusion really doesn’t like that

so I canceled the command, went back into the sketch and drew a line that splits the thorns in half
I actually had already drawn it when dimensioning the thorn but made it a construction line by mistake

I quickly mirrored it to the other side and went back into the Revolve command
I made sure to select Cut in the Operation dropdown menu and deslected the coin in the Objects to cut window

after that I repeated the Revolve command with the inner part of the thorn shape and joined it with the coin

a few chamfers and fillets later it was already done

I personalized the coin with our FabLab’s logo but feel free to add whatever you want to the blank sides
you can download my Spinning_Coin.f3d Fusion file in the Download section at the bottom of this page
this kind of angled protrusion in a groove, print-in-place design is incredibly useful and I use it quite frequently
it is surprisingly easy to 3D print but subtractive manufacturing wouldn’t work for this at all since there is not enough space for any tool to remove material in the thorn area
a recent example of this is a travelcase for glasses which I designed as a test for our new 5-headed Prusa XL

also a few weeks ago some of the hinges on our GS Laser Systems lasercutter broke so I quickly designed and printed some replacements with the same mechanism

I wouldn’t necessarily trust these to hold much weight but since the laser’s cover is held in place tightly with screws on the side and they only ever need to hold for a few seconds during maintenance I figured it would be fine
then again if they break I can just print more replacements but still keep any safety concerns and risks in mind when attempting stuff like this
you can find both the Travelcase.f3d and the Lasercutter_Hinge.f3d Fusion files in the Download section at the bottom of this page
now let’s try printing a FabLab Coin!
for this I am going to use a Prusa Mk4 3D printer, which we covered in our group assignment and the PrusaSlicer software which you can find here
if you have never heard about slicers, they are pieces of software that translate a 3D model into machine readable code so the printer knows what it has to do to create that object
there are a lot of settings you can tweak to optimize the results but the default settings have come a long way and are a great starting point
first thing to do is of course select the printer and material you are going to use

next click on the little gear icon next to the Print settings dropdown menu
if you haven’t already done that, enable Expert mode in the top right corner
by default the 0.20mm SPEED preset should be selected, if it is not go ahead and change that in the top left corner
next head into the Skirt and brim submenu to set the number of skirt loops to 2, you’ll see why in a bit

leave the print settings menu by clicking on Plater in the top left corner
add your model (in my case the FabLab Coin) by clicking on the icon in the grey bar at the top
in the bottom right corner you will find a button labeled Slice now
clicking this will generate a toolpath for the loaded model with your current settings
it will automatically switch into preview mode which you can use to “debug” you toolpath
you can drag down the + icon at the top of the bar on the right hand side to scroll through the layers of the print
see the greenish circles around the coin? those are the skirt loops we added earlier

their purpose is to help clean off any bits of molten plastic that are still stuck to the printer’s nozzle
most printers have a built in routine at the start of the print where they probe the printbed for any differences in height they have to compensate in order to produce a better first layer
in the case of the Prusa Mk4 this is done by tapping the hot nozzle on the printbed in a grid pattern
due to the hot nozzle being… hot… the loaded material can start to ooze out during this procedure and get caught on the side of the nozzle
these little bits of material can fall off at any random point during the print and ruin the surface finish
much worse, they can also fall off while printing the first layer and completely ruin it thus dooming the whole print
with everything set up and sliced all there is left to do is export the code onto a USB stick and head over to the printer

give the printbed a good cleaning with isopropyl alcohol (preferably before it has heated up) and start the print

always stay with your printer for the first layer, if this one fails, all the following ones will fail as well

when the print is finished, let it cool down for a little while before taking it off the build plate

Designing and printing a chainmail spinning top¶

Michael Bennemann, a student from 2023’s FabAcademy and colleague of mine showed me a really cool test print for metal powderbed fusion 3D printers. A small spinning top where the outer mass that keeps the thing spinning was made out of a kind of NASA chainmail equivalent.
Ever since our lab got a TRUMPF TruPrint 1000 metal 3D printer I wanted to try and print such a spinning top. Only barrier (besides the machine not working) was that I had no 3D models of this and had to design them myself.
I’ll be honest, designing this in Fusion is not easy so if you know of any design tools that would make quicker work of it, please let me know.
Anyways here is my design process:

you are going to need two offset planes that are 3mms from the XY plane and a plane that goes through the Y axis at a 120° angle

on the bottom plane start a sketch and draw a hexagon with a width of 7mm and include lines from the center to the middle of the side lines, these are going to be helpful later when we start creating patterns of the chainmail element

start another sketch on the top most plane and project the hexagon by pressing P and selecting the whole outline with a double click on any of its lines

next start a sketch on the angled plane and connect both of the hexagons’s points that intersect the plane with an arc, add a tangent line of arbitrary length to both ends

head to the CONSTRUCT menu and create a Plane Along Path
select the arc and drag the plane to its end or simply type 1 in the box labeled Distance

another plane, another sketch… draw a center circle with a diameter of 1mm

start a Sweep command from the CREATE menu and select the circle as a profile, for the path select the arc from before

create a new plane the goes through the “tangent line of arbitrary length” at a 60° angle

this is the part where it can get kind of tricky, project the center point of last sketch’s circle as well as the Z axis into the next sketch and start a spline
it should begin at said center point and end somewhere on the projected Z axis
click on the spline to reveal its handles and select the one from the start, add a horizontal constraint so the spline is properly aligned with the arc from before

while still in the sketch go into the top view and roughly align the spline’s end point with the origin point

start a sweep with the circle and the new spline but make sure you set it to output a new body instead of joining it to the existing one

mirror it along the first angled plane and also make sure that it generates a new body

we haven’t created a new plane in quite a while so let’s quickly construct one that is at a 30° angle from the Y axis, thus making it perpendicular to the first angled one

I am getting dizzy writing this but mirror the recently mirrored object along the new plane, again creating a new body

now it is finally time to join them with the Combine command and probably create a brand new pasta shape in the process
if you are not quite satisfied with the shape remember that the spline is still adjustable

next start a circular pattern, select the combined body and arrange it 6 times around the Z axis, make sure to select join this time

to add a little more rigidity you can add a circle to the origin and extrude a pillar out of it

after that create an offset plane from the XY plane, in the Extent dropdown select To Object and click on a fitting point like this one

do the same thing for the top and split the body with the new planes

select the excess parts and remove them just as a little cleanup

since I have no idea about the engineering behind building spinning tops I used this image from Gigazine’s article about the ForeverSpin 2.0 as a reference

simply head to the INSERT menu and select Canvas
Fusion will ask you to select an image and the plane or face you want to put it on, I had to adjust its position a little to lign up its center with the origin point

rightclick the reference image in the browser and select Calibrate

your cursor will become a + sign with which you can select two spots on the image and enter a distance between them in order to scale the entire thing

this unfortunately moved the image in a weird way so I had to realign its center with the origin

the chainmail element seems kind of big doesn’t it?
I scaled up the image one more time and added a pillar to the bottom of the element, which is going to be used as a support structure

remember when we created the first sketch and I told you we would use some lines for patterning purposes later down the line?
reenable the first sketch and start a rectangular pattern
select the chainmail element and for the axes select both lines from the sketch
set the distribution type to Spacing and create a symmetrical 9x9 grid with 9mm distance
check the Suppression box and deselect the elements you don’t need for a hexagonal pattern

now that there are so many different bodies with roughly the same name you should consider creating subfolders to keep your browser organized

start a new sketch on the YZ plane
project the bottom of the center support pillar and from there draw a line straight up (I went with a length of 62mm)
at the bottom create a circle that will form the tip of the spinning top
now start a spline that goes from one side of the circle to the top of the line, roughly following the contour of the reference image

start a Revolve command with the face that the center line, circle and spline created
make sure that you create a new body

some of the loops from the moving parts are stuck inside the main body so they wouldn’t be able to move freely

fine tune the spline so there is no connection anymore
combine the main body and the inner circle elements

the last thing to do is remove the unnecessary support pillars
a quick and dirty way is to simply select them and hit the DEL key but I’d suggest using the Remove Face tool instead

and there it is, the spinning top model is done

usually you would now go ahead and right click the body you want to export as a 3D model for slicing and printing purposes but since there are so many elements that are not directly connected we need to right click the entire component and select Save as mesh

my weapon of choice for this print is going to be the Bambu Lab X1 Carbon with a 0.2mm stainless steel nozzle, you can read more about the machine on our group page
since this is going to be more of a torture test for the printer I am really just freestyling the settings in Orca Slicer, a popular fork of Bambu Lab’s Bambu Studio
unfortunately I massively overestimated the stability of 17mm tall pillars with a diameter of 1mm so I had to cancel the first print
still quite impressive how far it has come

I went back into fusion and changed the support pillars to be based on 3mm squares
of course I had to also change some other commands to be compatible
instead of joining the support to the chainmail elements I set their extrude command to create a new body, this way I was able to remove them from the inner circle entirely

back to slicing and printing…
like I said I usually freestyle the settings, this time I changed up the preinstalled 0.10mm High Quality preset a little to fit my needs
I changed the wall count to 6, infill density to 25%, skirt loops to 2, brim width to 8mm and enabled manual supports which I painted onto the bottom side of the main body

almost 9 hours of print time are quite a lot for a model that doesn’t even weigh 20 grams
I wish I had positioned the model a little closer to the camera but isn’t this mesmerizing to watch?

the fact that this has been printed successfully with an FDM machine is even more surprising to me, an SLA 3D printer would have probably made quick work of this
the support pillars have still gotten a little wobbly, especially in the outer corners, maybe some bridges between the pillars could have helped
time to carefully remove the support pillars and give it a spin

Hecc yea 😎

As always you can find the Fusion files for this model in the Download section at the bottom of this page

3D Scanning with the Einscan Pro 2X Plus¶

For the 3D scanning part of this week’s assignment I used the Shining3D Einscan Pro 2X Plus and their EXScan Pro software. I scanned a FabLab Coin, cleaned up the scan data and printed the result to compare the print of a scan of a print to the original print. Let’s get started.

I loaded up EXScan Pro and noticed that the last calibration of the scanner had been done almost 3 months ago, so I thought it would be time for a new one

the calibration menu has really nice step by step guides, but it doesn’t warn you about flashing lights, which is exactly why I am mentioning it right now

with the scanner successfully calibrated I headed back over to the scan menu and selected a fixed scan
I set up a new project with the Non-texture Scan setting

I didn’t want to have to turn the coin so I tried placing it up on its side, but it kept rolling away so I stuck it down with some playdoh equivalent

next I adjusted the scanner’s brightness to make sure it picks up the markers on he turntable and the coin’s surface

the scan completed quite nicely but carried the markers on the turntable with it

I selected the lasso tool and drew a circle around the coin with it
after that I clicked on the Invert button and hit DEL on my keyboard to get rid of the markers
next I clicked on Apply Edit and headed over to Global Optimization which I confirmed immediately

the next step was meshin the model and post processing
I selected the watertight mode and went with the default settings

the results are not as clean as I had hoped but should be printable nontheless

lastly I confirmed all changes and saved the scan as an stl file which I quickly sent off to one of our Bambu Lab X1 Carbon 3D printers

and the results are… well… capable of improvement I would say

the parts have completely fused together and there is no sign of a hinge ever existing, I had to cut off a little bit of the bottom to get a printable first layer so the text has completely vanished and the logo has seen better days as well
for a first quick scan I guess it is pretty decent but can definitely be improved upon by tweaking some settings and maybe applying a thin coat of scanning spray to the scanned part

Downloads¶

Spinning_Coin.f3d

Travelcase.f3d

Lasercutter_Hinge.f3d

Chainmail_Spinning_Top.f3d