On May 14, we were represented with a booth at the Open University at the Lower Castle. In our luggage we had a couple of 3D printers, our robotic arm, as well as our augmented reality sandbox.
Spread over the Lower Castle Square, a lot of institutions and study programs and research projects were represented to introduce themselves. We were very pleased that many of you visited us. Sure, the weather was nice and there was an ice cream truck right next to our tent.
At the booth, visitors were able to learn how to use the 3D printer, and there were many interested visitors who were able to go home with their own printed parts. Our robotic arm, has been blithely demonstrating all day how to 3D scan and digitize objects (to then replicate them with the 3D printers, for example). The augmented reality sandbox was particularly well received. You can interactively change a topography of a map with the sand, build mountains and valleys, and then watch the flow of water on the map with a water and rain simulation. A great way to learn about topography and augmented reality.
My father bought the thing at the flea market sometime. The price of 5 rubles (Ц. 5Р.) is incorporated in the handle, because at that time in the Soviet Union there was the planned economy and you could get a pack of butter for the same price in the big whole country.
The drill always did its job. It is particularly suitable for small jobs and you can dose the torque manually. Only at some point the drill got stuck somewhere and my father exerted too much momentum on the big bevel gear until a few plastic teeth sheared off, rendering the thing useless. The old bevel gear consisted of two parts: The front side with the teeth was made of a plastic casting and the back side was made of some kind of metal, which was somehow connected to the plastic (unfortunately no photo). So a new bevel gear was needed.
First, the teeth of the bevel gear had to be counted. There are 60 teeth. The driven bevel gear has 15 teeth, so there is a ratio of 1:4. In addition, all dimensions, such as the height of the teeth, their width and the bore diameter of the bevel gear had to be measured with a caliper gauge. The problem: the teeth are not simply arranged in a straight line, and their “focal point” is somewhere in the air. They are also wider at the outermost diameter than at the inner diameter of the bevel gear. So the geometry is a real challenge and you can’t just build the thing with a CAD program if you’re not a professional.
But what to do? Fortunately, I happened to come across a solidworks tutorial on the internet. It shows how to create configurable standard parts using the solidworks (SW) design library. And that worked well!
Open Solidworks, open any assembly and throw out all the parts. Somehow it didn’t work out any other way for me. Then, on the right side of the screen, open the construction library and shimmy through the tree. Toolbox, ISO, power transmission, gears, degree bevel gear (driving).
For me, the ISO standard matched well with my Soviet part. Then the “Degree bevel gear (driving)” must be dragged and dropped into the assembly window. Now the “Configure component” dialog opens on the left. The module, the number of teeth, the pressure angle, etc. can be set. Here you have to experiment, have the bevel gear with the green check mark built again and again and measure it. (Tip: If you click on a component edge, the bottom info bar of SW conveniently shows the measured length directly).
However, you cannot specify all dimensions and geometry properties in the configurator. And here’s where it gets a little tricky. If the tooth geometry of the blank created fits so far, the rest must now be added manually. I used the function “Attachment/Base rotated” to build a created sketch as a body of rotation to the blank (see screenshot). Again, I had to measure the old bevel gear over and over again.
Once you are satisfied with the part, you need to export it to *.STL format for 3D printing. And off we go to the Fab Lab Siegen! Here Fabian helped me out, showed me the 3D printers and started the printing. Thanks a lot! 😊
The first print was unsuccessful (of course). In 3D printing, for example, the holes are always slightly smaller compared to the model. The teeth were also too small, so that they could not engage deeply enough with the opposing teeth. These teeth also sheared off during initial attempts. In addition, the bracket for the crank was a bit too thin and is therefore broken off.
But now it was possible to measure the printed bevel gear and improve the dimensions in SW and finally start a second attempt. However, the second time it went better than expected and the bevel gear installed beautifully. The hand drill runs very smoothly and if any problems should occur in a few years, I’ll just print out the bevel gear again 😉 .
During the summer semester 2020, there was a printer in the Fab Lab that was constantly cancelled for testing. The printer with the name “Hades” had to serve as a test object for a children’s book. But what does a children’s book have to do with highly experimental, plastic-saving techniques? Let’s lunge a litte bit.
Earlier this summer semester, I decided to develop a children’s book for 3D printers. Together with my fellow student C. Ajiboye, this became a manual that tells a story on one side, one of Ursa, a girl exploring 3D printing through “Learning By Doing.” On the other side, there were explanations of how Ursa finds problems and what solutions it gives for each of them. But the last page was special:
A WLAN-enabled (ESP32) microcontroller was embedded in this page. This one could feel touches via its touchpins. I then soldered these pins to copper surfaces and hid them under the page. One laser cut later, the copper surfaces could be seen shining through.
Thanks to these surfaces it was now possible to give commands to the ESP32. And thanks to the Octoprint servers, it was then possible to give commands to the printers. Yes, you read that right, this little book has a remote control for a 3D printer built in.
But What is the Point of All This?
Restarting a 3D print is not an easy task, so far there is not a single Octoprint plugin that dares to do this. The result is that when a print fails, which the sensors do not notice, a lot of time, sometimes days, and also up to kilos of plastic are lost. This book was intended to prevent that.
A book has many advantages: it’s quickly at hand, it’s often where you want it, and the software doesn’t change much. It is also lighter than a laptop and thus handier to use. What’s more, you don’t have to boot it up or preconfigure it. The interface is simply there.
But How do You Restart a Print With a Book Now?
A 3D print is stored in machine code. This “code” is written line by line and executed line by line afterwards. So a group of lines represents a layer, because a 3D print is done layer by layer. If a 3D print fails at one point, the commands could be executed again from this point. In the file, as well as in the real print, an exact height is defined for this. You could measure this height, but neither with the eye nor with a ruler you can find it exactly. With the 3D printer itself, on the other hand, you can find the exact height. Like calibrating old 3D prints, you can now use a piece of paper and the tip to determine to within 0.1mm where a print failed. So, with the book in your hand, you move the nozzle exactly over the pressure, lower it very slowly, and try to feel with a piece of paper placed in between when the nozzle touches the pressure.
The printer then knows exactly where this nozzle is located, if it is still referenced. Based on this height, the code is then split, the necessary initial steps are executed and then the printer prints again as if it had never stopped.
I Want This Too
After this semester I found the time to develop this project as a plugin for Octoprint. So you don’t need your own book and you can try it out in the web interface. But ATTENTION! This plugin is highly experimental and has also once caused damage to a 3D printer. I do not make any guarantees or take any responsibility for future damages and advise to always hover with your hand over the emergency switch until the first layer prints again and you are sure that the printer is working on the correct line.
After the closure is before the start of production. After all, we, like many other public institutions, had to cease our operations on March 16. Now there were a dozen 3D printers standing around unused. MakerVsVirus and other ideas and projects that developed online in the following days invited us to do something against the virus.
Well, to make a long story short, we are now producing facial visors to reduce the risk of infection to medical personnel and other at-risk groups(the hip girls and guys also call them covid shields). The visors are given free of charge to medical facilities.
As part of the cooperation project “Garbage – Environment – Design“, Sarah and Marios, two of our students, travelled to Palestine last year in September. The two-week project, organised by the Goethe-Institut in Ramallah, was intended to counteract the throwaway culture in public spaces from Europe that prevails there and to build a bridge between consumption and art. For this purpose, approaches of “upcycling” should be used, which make something new out of something old.
Two students each from Germany, France and Palestine were involved in the intercultural project and designed the exhibition and built matching exhibits in a workshop. During the ten-day stay on site, prototypes were to be produced collaboratively from everyday objects through upcycling in order to draw attention to everyday environmental problems. The project benefited from the input of other Palestinian and international experts from the fields of design, art, education and architecture.
The material such as pallets, Yton stones and plastic bottles were picked up directly from the street and were only a part of the countless resources used.
An example of the effective use of materials are the hanging gardens consisting of two green bottle walls planted with mint, which were set up to welcome exhibition visitors at the main entrance of the Goethe Institute. The results were exhibited in the Franco-German cultural area for intercultural discussion and experimentation.
In addition, during the students’ visit to Palestine, the action day “Art and Consumption” took place, in which the residents were to actively and collectively clear a piece of land of rubbish and litter.
The aim of the project was to communicate civil rights, but above all civic duties, and to mobilise local young people in particular to take on civic responsibility. Among others, the project was carried out in cooperation with Vecbox, the first Palestinian Makerspace, who brought local expertise.
In the last two days I have been working on retr0bright and I don’t want to withhold my experiences from you. I’m currently retrofitting this old Playstation 2 controller and was actually going to limit myself to the inside, but now I’ve decided to give the controller a bit of a facelift on the outside as well.
However, the primary goal was not to make the controller look nicer again, but to simply have retr0bright done. So I looked around in this internet how retr0bright works and what you need for it. You can find many different recipes and procedures. All involve hydrogen peroxide (H2O2) solution 👨🔬 and (UV) light. I was inspired by this video first and decided on the H2O2 and heat variant:
For this I bought a 3% hydrogen peroxide solution. You can get them for a few euros at Müller or Amazon. To test the procedure, I first performed a small test. There were two parts on the controller that had to be replaced due to damage and could therefore be used as a test and reference object. Before the test, I removed the protection from the parts.
For the H2O2 & heat variation, I mixed the H2O2 with tap water in about a 1:2 ratio and heated it to about 60°C in a pot, then let the first part float in the solution for four hours. Even though no additional light source was used in the video, I still decided to shine a lamp into the pot. Since other tutorials keep saying that the best results can be achieved with ultraviolet light or lots of light in general, I took the brightest/intensive lamp I had there. This is a 50W high power LED which is normally used as plant lighting. But I can’t tell you exactly what wavelength comes out ¯_(ツ)_/¯.
After four hours, I then took the part out of the solution and could perceive a visible brightening, with which I was satisfied.
So in go the next parts. Since I had bought only a small bottle of H2O2 (250ml) and accordingly there was not so much liquid in the pot, I first put in only the front sides of the joysticks, since they are somewhat flatter. Important: the parts should be completely covered. After four more hours, I took out the fronts of the joysticks and compared them to the backs.
I treated the backs using the same process, but I had to improvise a bit because I didn’t have enough of the hydrogen peroxide solution to completely cover the backs. So I decanted the solution into the jar and added some more water and then heated the solution by water bath. This time I couldn’t set up the lamp properly, so I left it out.
After another four hours, I got the parts out. The whitening was much less than the other pieces, so I just let them float in the solution for another three hours. Unfortunately, this did not bring so much.
Since the actual controller housing is way too big for my pots, I used a different variant here. For large housing parts, the Internet recommends the use of hydrogen peroxide gel. In this process, hydrogen peroxide is mixed with glycerin (among other moisturizing properties) and xanthan gum (E 415, thickening agent). Alternatively, you can use Oxide Cream from the hairdresser: https://www.amazon.de/Cream-Oxide-1000ml-12/dp/B008F5MIL6/ (see reviews).
The procedure here is as follows: The part to be bleached is evenly coated with the gel and then, if possible, wrapped airtight (zip lock bag or cling film) and placed in the sun or under a lamp for about 24 hours. Wrapping is to prevent the gel from drying out too quickly.
The aluminum foil serves only as protection for the table. Then quickly built a bracket for the lamp 👨🔧.
After about 24 hours, I then freed the case from the cling film and washed it properly. It has become brighter, but unfortunately not as much as the other parts.
I also put the backs of the joysticks under the lamp overnight. In the morning, the parts looked like this:
A photo series was created from a plaster face mask.
A point cloud from the photo series was created with Linux/Colmap.
The points were cleaned up and processed with Meshlab
The milling paths were generated with Pycam.
The toolpath files were created with a tool developed in-house.
simplified so that the GCode can be run with the Fablab CNC software as well as NCcad.
The workpiece: a 1 1⁄2 year old, dried piece of end-grain wood, pre-drilled for “spaxing” onto the sacrificial plate.
Cutter: 6 mm cylinder for “roughing” and 6 mm spherical head for “finishing”.
About The Manufacturing Process
The feed rate for milling could be increased significantly. The cutter length was not sufficiently taken into account during the creation. This is how the saying of the day came about: “One more delivery is possible”. Before any collisions occurred, it was stopped. After remodelling and x-times finishing (Proxxon), the following emerged:
This project was kindly supported by the University of Siegen. Many thanks for this, especially to Daniel for his collaboration and Helga for text drafting and layout.
Remark: Only a very slow Linux notebook (Ubu 19.04) is available on site. (possibly faster with SSD or cloud computing ??) Network access for updates planned. Friday afternoons are aggravating and not so well suited for such projects with public traffic and the limited time of the staff. Other spax screws are missing or have not been found. The cutter selection is limited. Unsolved : Chatter marks.
On the evening of that December day in 2019, I held in my hand the first copy of a 3D print of one of my designs.
I have been working artistically with multipart images and objects since the 90s and was looking for a method to transform a design into a sculptural object from the 3D printer.
Members of Fab Lab Siegen accompanied me in several steps: From the basic information about the Fab Lab and its possibilities, the ways of designing from “my” graphics programme via CAD programmes to the printer control, a lot was new for me. But in the great working atmosphere it was fun to get involved with new things.
Now the new object hangs provisionally on the wall, for “test viewing”, so to speak. I am concerned with the mechanisms by which our perception “sees” something as a whole with the help of partial information. The quality of visual information, redundancy, the “information gap” – such terms run through my head.
Here in the work you can see how, despite the distances between the stripes, the impression quickly arises in many places that rectangles, seen in perspective, are being depicted there. The gap suddenly becomes information. With David Amend at the end of the day, I got to talk about how the exact same thing is happening with fake news, an area in which he had experience from a computer science perspective. This is how fragments become a narrative and how easily “truth” emerges in our minds. That brings me back to my artistic theme.
If you want to go a little deeper, you can find more material on my blog.
In archery, the repeatability of the entire shooting process is
crucial for a good result. I myself have owned an Olympic recurve bow with sights (aiming device) and stabilization system (weights for balancing, for smoother aiming) for several years.
Characteristic of this type of bow are the curved or backward bent ends of the bow, from where the English term “recurve” comes.
Unlike other shooting sports, where, for example, is shot over the rear sight and front sight, the sight of the recurve bow has only the front sight. Thus, the body posture and the stopping point of the bow (anchor point) form the second reference point of the recurve bow to define the direction in which the arrow flies. That is, even if the front sight always points to the gold (center of the target), but the bow is slightly different in your hand than it was when you shot it before, the arrow will hit somewhere else.
Therefore, many archers customize the grip of their bow with grip tape or modeling clay to craft a grip that is perfect and stable in their own hand. Since I was not satisfied with the grip of my bow, I decided to design my own grip, which also looks professional due to 3D printing.
Attempts to apply known knowledge
Before I designed the grip according to my ideas, I first wanted to copy the original grip of my bow, so that I could make the adjustments that seemed reasonable from this basis.
Due to my mechanical engineering studies at the University of Siegen, I am familiar with the use of CAD software and have confidently approached the design. However, two things caused me an unexpected amount of problems.
First, it took me a long time to design the many interlocking fillets of the handle. These fillets are very difficult to reproduce with software solutions from the mechanical engineering sector, since they usually have defined geometries. This took me some time, but also forced me to learn new features and capabilities of CAD software.
The second issue that cost me a few tries in 3D printing is the measurability of the hard-to-define geometries.
Since the handle has only a very narrow, straight edge, it was very difficult to measure the position of the hole, bevels and radii. However, it is important for the attachment of the grip piece to the sheet that the geometry of the grip piece corresponds exactly to the geometry of the receptacle provided for it on the sheet. Since I could only roughly estimate many dimensions, I had to approach the correct geometry step by step through trial and error.
During this trial and error, I was able to learn a lot about 3D printing from the staff and makers in the Fab Lab. Above all, they helped me find the ideal slicer settings for my part and the right material. In addition, the Fab Lab works with different CAD programs, all of which have their strengths for different problems.
After four attempts I had copied the original grip of my bow sufficiently well and started with attempts to adapt the grip geometry to my hand. In the process, I tried a total of five different versions.
First, I made changes that seemed logical to myself to stabilize certain areas of the hand to prevent it from slipping back and forth. On the other hand, I combined this with geometries of grips from different manufacturers to arrive at my individual and optimal grip.
Currently, I have mounted a version of the grip on my bow, in which I have rounded some disturbing edges of the original grip and minimize the back-and-forth slipping by changing the angle of the contact surface.
Satisfied, but surely there’s more?!
I definitely achieved my goal of getting a better grip than the old one. Whether I have already found the ideal solution, I do not know, because there are still some geometries that I could try.
In the meantime, I uploaded the latest version of the grip to Thingiverse and hope to run into an archer who also uses my grip. Overall, I have to say that through the exchange in the Fab Lab I got ideas and tips that I would never have come up with on my own.
When I entered the Fab Lab for the first time in November, I was really amazed that there was such a great place here in Siegen. The people were very nice and open-minded and I felt comfortable right away. I guess it’s also because I’ve always been a bit of a technology nerd.
An Idea is Quickly Found
The 3D printers have aroused special interest in me. Not only because it was exciting to watch them work, but also because I am somewhat involved in 3D modeling as a hobby. Over the next few weeks, I was at Open Lab every Friday. There I met many nice, interesting people who were all working on great projects.
I think creativity is somewhat contagious. Therefore, it did not take long and I had also decided on my first project:
i wanted to create a tabletop game, model all the game pieces myself and make them with a 3d printer.
Since I had just rendered a great picture (see below) of a “MechMiner” for a science fiction contest, I took it directly as a template for my first figure, the “resource collector”.
The Right Manufacturing Process
Then I just started modeling. In doing so, I often reached the limits of the FDM printing process due to the small dimensions of my figures and the many details in the 3D models. Therefore, I considered a modular plug-in system to be able to print as efficiently and detailed as possible. I was offered to use an SLA printer, which has much higher precision, but dealing with resins and other liquids is not really my thing.
Build, Build, Build
With most problems, both in modeling and in manufacturing, someone was always ready to help me. Since the laser was a little more complicated to use than the 3D printers, I was also quite happy about it.
Since the laser was a little more complicated to use than the 3D printers, I was also quite happy about it. This one was perfect for making a nice modular game board. At the moment the game is not finished yet, so here you can see only a prototype for testing the game mechanics.
It will be some time before the first version can be played. Balancing will take a long time, and there are still many game cards to be designed.
I have already put the 3D models into a Github project. Stay tuned!
And Around It: The Lab
I myself could also help some people with their projects with my knowledge, and it makes me a bit proud :). I think coming together and working with like-minded people is what makes Fab Lab such a great place.
The technical competence of the staff is high and they do their work very professionally.
The Lab provides opportunities for everyone to try out technology. And I definitely found some people there that I would call friends.
In the meantime, I own my own 3D printer to move the project forward. Thanks again to everyone who helped set up and troubleshoot!
In my opinion, a place like the Fab Lab is an enrichment for Siegen. I just don’t understand why so many people walk past it. 😮 Anyway, I’m looking forward to spending more time there.