Last week, the STEM participation days took place. From 13.09 to 15.09, the Fab Lab team was invited by the district of Siegen-Wittgenstein to the front plaza of the district house. Every year in September, around 1,000 children and teenagers from all types of schools and daycare centers take part in a wide variety of STEM offerings for experimenting, experiencing and discovering. The Fab Lab was part of the various research and discovery stations as an extracurricular learning space.
The team had prepared a workshop on the introduction to 3D printing. A total of six groups of students from the eighth grade upwards from secondary schools and grammar schools took part. A small, mobile Fab Lab was created in a tent for this purpose. We brought a total of six of our eight Prusa 3D printers and ten of our laptops.
First there was a short theoretical introduction to basics, design principles, hazards, modeling and slicing. After a short demonstration part, the pupils were allowed to get hands-on: they could create their own key chains in the free software Tinkercad. Once the model was ready, the students transferred them to the slicer, prepared them for 3D printing, and were then able to print their designs on their own. Of course, we were there to help the students with any questions or problems they might have. For example, pendants with initials and names, or objects such as swords and ping-pong bats were created. The students were allowed to take these home at the end of the workshop.
Despite the rain, the sun was shining inside the tent: we were very happy about the engagement and interest of the students and hope we gave them some understanding of 3D printing!
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.
On thirst…thursday, July 7th, 7pm: Sandstr. 26 in Siegen!
Dance, game & drink the night away! Play a round of Mario Kart (Switch & SNES) or Street Fighter 2 (SNES) with (or against) us. Let’s celebrate the end of the semester with plenty of drinks, tasty vegetarian & vegan food and good music.
Everybody welcome! We have food and beer, all for free. No regristration needed.
In addition to our opening hours for the Open Labevery Wednesday from 14 p.m. to 20 p.m., this summer term we also have times when the Lab is open specifically for students. As of now, students can also work in the Fab Lab on Tuesdays and Thursdays during the following times:
Tuesdays from 13 p.m. to 16 p.m.
Thursdays from 14 p.m. to 17 p.m.
These extended opening hours are directed towards students of the University of Siegen in order to offer additional times to work on their projects. Individuals not affiliated with the university are welcome to come to the Open Lab on Wednesdays as usual.
Finally, we are back with good news! The Fab Lab will re-open at the beginning of the summer semester. We are thus happy to announce the date for the next Open Lab:Wednesday, April 06.
However, given the still very high number of corona cases, we have a few recommendations for visitors to the Lab:
Within the Lab we recommend to maintain the3G rule(genesen, geimpft, getestet = recovered, vaccinated, tested). Furthermore, it is recommended to wear a mask at all times. Of course, the mask may be removed for drinking, but we would kindly ask you to put it back on immediately afterwards. For this reason, open drinks (e.g. coffee/tea cups) are currently viewed with caution, as experience has shown that these lead to “Kaffeeklatsch” 😉 Instead of eating right at your workplace, we would like to ask you to consume your foodat the open (!) windows in the lobby at Startpunkt to ensure the safety of everyone staying here.
The number of visitors in the Fab Lab is limited to a maximum of 20 guests.
Given the current incidences, we have decided to keep the Fab Lab closed until further notice for the safety of all of us.
Aconcrete date for reopeningcannot be set at the moment. As soon as the pandemic situation allows us to safely open the lab again, we will announce this here on the website, via email and social media.
In urgent cases, e.g. for work on a thesis or other projects, please contact us and we will find a solution.
In the view of the anticipated course of the pandemic in the coming weeks, the University of Siegen has adjusted its measures. All buildings of the university will therefore remain closed to the public up to and including 06.02.2022. At this point it is not yet clear what will happen after that.
Regarding the Fab Lab, this means that there will be no Open Lab until at least the 06th of February. Contrary to our previous statement, there will therefore not be an Open Lab on Wednesday, January 19. We hope that we can see you again on 09.02., but we can’t yet promise this.
Finally the time has come, from Wednesday, October 13 we open once a week on Wednesdays from 2 to 8 pm. We are very excited to welcome you to the new Lab at Sandstraße 26, on Reichwald’s corner, and to work (and drink mate) with you again.
The 3G rule applies, which means whoever is vaccinated, recovered or tested negative may come by. However, seating is limited to a maximum of 20 people at any one time. Masks are mandatory throughout the Lab (except at the workplace) and safety distance. Use of the Fab Lab is still free, but as always, everyone brings their own consumables.
It is also important that everyone, including those who have worked in the lab before, must take a safety instruction. Therefore, we are offering additional safety instructions on October 13 at 2 p.m., 4 p.m. and 6 p.m.. After that, there will be regular safety instruction on Wednesdays only at 4 p.m.
As usual, you don’t need to register or pay anything for the visit or the safety briefings.
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 😉 .
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.
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: