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5 - 3D Scanning and Printing

Hero Shot

Summary

This week we learned about 3D printing and scanning. We got to know the machine at de Waag and printed a little item that could not be made subtractively.

Approach

This week I was inspired by the simple logic of a bead curtain — solid beads that become flexible when connected. I translated that idea into a small print-in-place object, focusing on movement instead of complexity. By testing clearances in prints and adjusting the spacing between parts, I explored how careful design allows separate elements to move freely after printing.

Assignment

  • Group assignment:
    • Test the design rules for your 3D printer(s)
    • Document your work on the group work page and reflect on your individual page what you learned about characteristics of your printer(s)
  • Individual assignment:
    • Design, document and 3D print an object (small, few cm3, limited by printer time) that could not be easily made subtractively
    • 3D scan an object (and optionally print it)

Test our 3D printers

We tested four different 3D printers in our lab, unfortunately two of them had some issue due to prior use and we couldn't complete our benchmark test. On the other two we did manage and then got to use these for our individual assignments.

Before we got printing however Henk showed us how to use Prusa Slicer to turn an STL file into G-code that can be read by the 3D printers. After loading in the STL file Henk showed us a bunch of configuration options, here are the most important ones:

  • Print settings: control the overall quality, speed, and layer height of the print.
  • Printer: defines which machine is being used and its physical limits.
  • Filament: specifies the material type and its temperature requirements.
  • Infill: determines how solid the inside of the print will be and which pattern is used.
  • Support: decides whether supports are generated only from the build plate or everywhere, and whether they use an organic or grid structure.
  • Skirt/Brim: adds extra lines around the print to improve adhesion to the build plate.
  • Filament diameter and density: ensure the printer extrudes the correct amount of material.
  • Nozzle diameter: defines the width of the extruded line and affects detail and print time.

Henk showed us a small all-in-one printer test we could use to compare the different printers in the lab. We loaded this into Prusa Slicer and exported the G-code onto an SD-card. Then Henk showed us how to clean the build plate with alcohol, which you need to do with any 3D printer before you start printing. Also make sure you cut the filament so it has a clean edge to load into the nozzle of the printer.

Prusa i3 Mk3S

The first printer we tried was the Prusa i3 Mk3S. To print on this printer we followed these steps:

  • Load filament through the tube in the roof of the machine and into the nozzle
  • Select "load filament" from the menu, wait for the nozzle to heat up and guide any filament spilling out from the nozzle. Make sure no other colors are then the loaded filament is coming out of the nozzle and it extrudes smoothly without noise.
  • Select the design from the SD card
  • Watch it go

Unfortunately the machine didn't run smoothly, it made some clicky clacky noises and Henk got worried. He showed us how to alter the temperature of the nozzle while it's printing. We tweak this in an effort to get it to run smoothly, but it didn't seem to matter. Henk stopped the machine and fixed it for us.

Prusa CORE One

Next up was the Prusa CORE One, which is a more recent design from the same company. Compared to the MK3S, the CORE One uses a CoreXY system, where two motors work together to move the print head in the X and Y directions while the print bed only moves up and down (Z). This means less moving mass, which allows for higher speeds and smoother, more precise motion. The MK3S, by contrast, moves the entire bed back and forth in Y, which is simple and reliable, but can introduce more vibration at higher speeds.

The CORE One also has a rigid enclosed frame, meaning the structure is more box-like and closed off. This increases stability (less vibration during fast prints) and helps maintain a consistent temperature inside the printer, which is useful when printing materials that are sensitive to drafts or cooling.

To use this printer we first run through the steps we do each time: load our design on a SD-card, clean the build plate and trim the filament. The we load the filament in the machine through the tube in the roof. The machine senses the filament and ask us to select the type. After this it let's us know whether to open or close the vent grill, always follow these instructions!

We wait for the machine to heat up and check the filament runs smoothly, then select our design from the SD-card and watch the machine get to work.

This one actually came out pretty good. You can tell this combination of filament and printer gets some issues with the horizontal overhang and the longest bridge came out a little wonky, but overall it looks pretty good.

When comparing the tolerance you can tell the machine has a nozzle of 0.4mm.

Ender

We then moved on to the Ender 3 by Creality. This printer requires manual bed leveling before printing. Start by placing a sheet of paper on the heated bed and cleaning the nozzle. From the display on the right side, select "Prepare", then "Auto Home" to move the printer into its starting position.

Once in position, adjust the build plate using the wheels underneath each corner. The goal is to set the distance between the nozzle and the bed so that the paper slides underneath with slight resistance — it should not be loose, but it also shouldn’t be stuck.

Move the nozzle to each corner and repeat the adjustment process. Finish by checking the center of the bed to make sure the surface is evenly leveled across the entire print area.

Unfortunately this machine also had some issue with the heating of the nozzle that caused the print to fail. Henk says he'll look into the issue, but we gave up on it for now.

On the left the print from the MK3S and on the right the Ender.

UltiMaker

Next up was the UltiMaker 2+, a cute little machine with a robot on the side. This machine uses a 2.85mm filament, unlike the other machine we've used this week which use 1.75mm. The machine talks you through the steps where you level the bed by tightening the screws till you feel traction with a piece of paper. We selected the printer in Prusa Slicer, exported and loaded up the G-code on the machine. The prints how ever didn't come out well, no matter how we leveled the bed, the machine seem to over-extrude.

After four prints we figured the problem probably wasn't with our little robot but in the G-code. I decided to check look through Prusa Slicer and noticed the software didn't update the filament diameter when I selected the UltiMaker. I then asked ChatGPT if it's possible to find the diameter in the G-code file and checked the file on the SD-card. Turns out it was indeed set to a smaller filament width, the machine was pushing through way more filament than the code expected, over-extrusion made total sense. We printed our little test model again and it came out a lot better.

Design an object

For my final project I'm looking into items that represent the hight of free trade and globalization and overproduction. For this I'm focussing on cheap, "made in China", plastic items that have a nostalgia about that era. In a previous week I looked at glow stick rings and this week my inspiration comes from the wonderful bead curtain.

Britney Spears, Robert Sebree 2000

I've been thinking they could be used to display information or be put full of sensors and respond to touch. Diving deeper into these shapes and how to connect them could be useful knowhow in the future. I'm also intrigued to learn whether I can get a smooth surface with a shape that will need support material at the bottom. Making the shapes not symmetrical allows me to print them both orientations and compare the result.

The idea is to make a couple of beads on a rod that can move freely, preferable each on their own little rod to add some flexibility. This is impossible to do subtractively, like on the lasercutter we used in week 3, since it can't be disassembled and includes overhangs. To make sure I'm not getting in over my head I'm focussing on spiral development:

  1. one bead about 3cm in length
  2. one bead on a rod that can rotate
  3. multiple beads with connected rods

For the last option I would also have to decide on a mechanism. This could either work with a chain of rods – each containing a bead, or the more elegant option, use a bead as connector between two rods, allowing for the rods to move add different angles from each other.

But YAGNI, let's start with making a 3D model of just one bead. This week I've decided to use Blender, since I've worked with Freecad in previous weeks. I couldn't entirely wrap my head around how to mimic the gemstone geometry in Blender, so I looked for a tutorial. Following these steps I made a basic faceted teardrop shape.

I then exported it to STL and opened it in Prusa Slicer to make sure there were no unexpected results. The size looks good and it shows where support material and infills would be.

Time to add a rod to my design, I add a cylinder and a boolean modifier to my bead to create a hole all the way through. Then I add a second cylinder through the middle to form the rod. I slightly scale the edges of the rod to make sure the bead can't escape.

Now I would like to add multiple beads and have them move sort of flexible to mimic curtain like behavior. Thinking of ways to achieve this I'm reminded of ball chains, which have inflexible rods, but are flexible over all. I do a bit of googling and come up with a way to mimic this behavior in Blender.

Image from the paper Granular chain escape from a pore in a wall in the presence of particles in one side: Comparison to polymer translocation found on Research gate

By creating a cavity in the bead and adding a little stopper to the rod I'm hoping the bead and rod stay connected, but can have a little wiggle. I load the STL file into Prusa Slicer again to check how the printer would go about the inner workings.

Unfortunately it splits the rod up into two separate parts, I figure it's probably something to do with the boolean operators, so I play around with them in Blender until the rod is seen as one object by Prusa Slicer.

I add another cavity and rod on the other side and decide it doesn't make sense to start adding more beads before testing the dimensions of my current design, time to do some printing.

Printing

1. One bead I state my journey by printing just one bead on the CORE One with 3dJake eco PLA and organic supports, it comes out pretty clean.

2. One bead again To compare I try the same bead on the UltiMaker with ColorFabb PlA/PHA in standard white with organic supports. Prusa Slicer creates more support material for the UltiMaker – which has a bigger filament diameter – than the CORE One. It was harder to get the supports off and the result is less clean. Since I'm really looking forward to testing the moving mechanism I designed I decide it's good enough for now and I can try different support options along the way, so I move on to a more complex print.

3. Bead with rod all the way through Since the print came out more clean I go back to the CORE One. Next print I do is one bead with a rod all the way through. In the 3D model the rod is floating inside the bead. I try a print with support material only on the base plate, so not inside the bead, this means the printer is doing mid air printing. I look as the print is happening and the distance is so small that a bit of filament just falls down and it doesn't distort the print much. It's good to realize however that this won't work on a bigger scale. When the print is done and I've taken the support material of it the first turn of the rod has a bit of friction, but the end result runs really smooth.

4. Bead with rod in cavity To mimic the bead curtain and ball chain movement I don't just want the rod to rotate, but for the rod to move more flexible from the bead. For this I designed a bead with spherical cavity where the rod has a little rim at the end to stay put. It still relies on mid-air printing, but since the scale is so small and it worked in the last print I decide to go ahead. The rod definitely has some flexibility all round, this is getting pretty cool.

5. Bead with two rods Since the bead isn't symmetrical the cavity in the top of the bead is a lot lower, this means the rod is stuck in the bead way deeper, which means it will be last flexible than the bottom one. I print this as well with the mid-air printing, cause this is my last mechanism test and it hasn't caused any problems sofar. It works out really well and is quite jiggly, although had I had more time I would have played around with the scale of the elements to add even more flexibility.

6. Mini support test Ok, it's super nice that the tests for mechanism worked out pretty well, but the mid-air thing would make it super unpredictable when you start playing around in size, so I'm wanna try to do it properly. Maybe if I design the support myself, just make a little connection with filament to support the rod. I quicly design a small test and do a print. I does not go so well, the whole print is too flimsy and the whole thing shakes while printing. This is obviously not the solution and this feels like a dangerous rabbit hole, Prusa Slicer is probably way better at designing support than I'll ever be.

7. Half sphere with rod I figure I could use Prusa Slicer's support settings to fine tune the support on the inside of the cavity to be enough to support the rod, but not enough to cause friction after prying them loose. To see the left-over support material on the inside of the cavity I whip up a 3D model existing of a half sphere so I can see the internals. I set the supports to 'snug' in Prusa Slicer and play with the overhang threshold until there is support underneath the rod rim, but the rest of the sphere isn't filled up.

8. Full sphere with rod Next up I do a full sphere to test the friction of the leftover support material with the rod. I switch back to the UltiMaker to give my classmates a chance to use the Core One. This one comes out really nice, it moves very smoothly at a really wide angle.

9. Full bead with rod Now it's time to test the internal support material in the mechanism I actually designed. Even though the cavity's size and shape is the same as the sphere in the previous test, it's deeper inside the bead, so the rod has less freedom of movement to scrape the leftover support of the inside of the cavity. Time to test if by printing just the bead with the bottom rod again. I also switch to a metallic filament, cause beads really should be shiny. This one comes out really well, you can feel some support material in the cavity for sure, but for the semi flowy movement of a bead curtain I think I could make this mechanism work with more time.

10. All together now Finally it's time to print my full design!! It consists of the bigger bead with two rods, which each have another smaller bead at the end. The CORE One is busy printing some metallic goodness for my classmates, so I switch back to the UltiMaker. The result may not be perfect, I'm pretty proud of the fact that it jiggles and doesn't rely on mid-air printing!

11. Printing sideways One final test I run, to try and get less damage from support material at the bottom of my print, is print a bead sideways.

It comes out so smooth and pretty I love it!

Scanning

In our Fab Lab there's a Ferret scanner by Creality and before you know it I was in a chair having my face scanned by Henk. Using CrealityScan on my computer we first 'fused' the point cloud, which turns multiple scans into one point cloud taking care of overlap and noise. Then we tried the 'Head AI Repair' option, which gave really creepy, slightly disturbing results. I puzzled around with the meshing options a bit and turn on the 'Fill Small Holes' and 'Closed' options. I end up with two noses and two mouths, but this gives me a model I can now use in 3D software.

I load up the model in Prusa Slicer and scale it small enough to be printed in under 20 minutes. I love how the organic supports look, like I'm a cool monster.

Then I print a teeny tiny version of me on the UltiMaker, how fun!

Files & resources

The scanning files are really large and kinda detailed versions of my face so I decided not to upload them here

Leftovers previous week

  • read through week 4 carefully one more time
  • update final project with latest developments
  • make assignments mom proof

Further exploration

  • would love to play around with the scale of my beads and rods more to add even more flexibility, maybe even print a whole curtain someday