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The temperature depends a lot on where and how you measure it, so it’s something you might have to try out a little. We measure in the heating element right now and pre-heat the mould for a while. And our favorite setting for the wheat bran is around 100°C.
Let use know, when you have the new mould and how it’s going with that! 🙂
the water resistance comes from the material being pressed properly. That means, when the mould closes completely and the moisture of the material can’t evaporate, it starts sealing the surface.
Therefore it’s important that the mould closes properly and that you use the proper amount of material for your mould 🙂
thanks for sharing your progress! 💪
To answer your question #1: There are a few factors that can influence the stickiness of the material to the mould. First off, what is your mould made from?
Can you post a photo of the mould as well?
The smoother the surface of the mould is, the less likely the materialy is to stick to it!
Second, the temperature you press at can play a big role in making it stick. Could you share a bit about your process (what temperature do you press at, how much pressure are you using, how long do you press for?) and maybe a photo of your press setup?
And last, you can use different oils or greases to make it easier to get the material out of the mould. We had good experiences with rice bran oil, since it has a high burning point and is still fairly cheap and available.
Hope I helped you a little already! And if you can put more information online, I’m sure we’ll figure it out! 🙂
Hahahaha, @pex12: Thank you for recognizing my welding talents. If you want to find out more about the art of welding, you can read my soon to be published book “weld it like it’s hot – weldcome to my weld” 🤓.
@s2019: Good thoughts! I made some modifications to the file, but now I’m a little scared about the strength, in case a mould is filled unevenly. Because the sides of the U seem so weak to me. Or is that just in my head?
And the concrete idea is just because I wouldn’t need aluminium blocks then and I thought it could make the structure stonger. But maybe I’m just wrong…
Anyways, here’s a screenshot of the changed frame. Let me know what you think!:)
So here’s a little update after working with the current press design for a while and trying out different moulds in it.
As I said earlier, we use the air compressor to control the force, but at some point turned it above the 8 tons, to see if one of the test we made would close with more pressure.Turned out we also tested the yield strength of the U-Profiles we used and permanently bent some of them.
Next mistake: I added another profile to counter the top part, but left the bottom one like it is.Now the top one seems to be able to hold the pressure, but the lower one is pretty bent still.In general I did realize in this process though, that the more stress we use, the better the products turn out. Moreover it feels a little bit like a waste, if we have a jack that can go up to 18tons and only use half of it. So it would be cool, to build the press strong enough, to hold the 18 tons.
Plus, that would also get rid of the problem of measuring the pressure, because you could just use as much, as you need to close the mould.
Now I have two ideas on how to change the design and would love some input from you girls and guys!
#1 To reinforce the press, I could just use bigger profiles and counter all of them. UNP profiles are easily accessible in 140mm width or higher everywhere. (the current one is 120mm wide)The bad thing about it is that the press would get more and more heavy and definitely less friendly in a way. Especially if you would want to make it mobile for workshops or stuff like that. And more material = more resources and energy spent in the process…
#2 I came across the second idea, when I saw this video by Lucy and her acrylic press.Her press uses heating elements made out of concrete and from my carpentry school I still remembered how we reinforce concrete with steel, because it can take a lot of pressure, but not a lot of tension, while steel is the opposite.So I am thinking now: Could I just fill my profiles with concrete to have a solid heating element, while at the same time, having a stronger profile?I have not too much experience with concrete, besides using it for table tops, so if you have any thoughts on this, I’m super duper interested! 🤓
Oh and this is the research they quote in the paper: https://www.sciencenewsforstudents.org/article/teens-use-science-worm-through-plastic-waste
The “teens” actually claim that the superworm is slower, but in my experiments they were definetly much faster. I guess there’s still some research to do 👨🔬
@donald yeah, I think the food safety one is super interesting, but at the same time it seems also far from reality, since it’s even hard for people in big parts of the world to imagine eating insects in the first place.
There is this Study by a German university: https://www.uni-kassel.de/fb11agrar/fileadmin/datas/fb11/Agrartechnik/Dokumente/Projektarbeiten/2017_Gaerttling_Projektarbeit.pdf
For everyone who doesn’t speak German or doesn’t want to use translation tools:
They were more focussed on researching the eating behaviour of the worms, the consequences for the population after a few generations of worms eating styrofoam and checking, if they can also digest styrofoam that is impregnated with fireprooving chemicals, which is heavily used as insulation materials in Germany. But they also always checked the worms and beetles for remaining traces of the plastic/chemicals and so far, they couldn’t find any.
Plus they made a good point about the Superworms, which I also found pretty fascinating, when I grew them: They only pupate when being separated. (Kind of romantic, that they can’t grow up, unless they are left alone for a bit 😉 )
This is pretty helpful, if you want to use them for recycling and have control over the population and when they turn into beetles.
Oh and @alfadriver I’m not sure I understand the question. Can you rephrase it for my monday-morning-it’s-so-hot brain? 🙂
Oh and I just started planning a little research month for the beginning of next year with biochemistry students from a university in maastricht and am collecting research questions right now. They have access to all the labs and equipment to go into all the nittygritty, so let me know, if you have good ideas.
So far I got some questions about how to treat the styrofoam “crumbs” that fall of, when they bite into the material. It’s possible to feed it back to them and have it digested, but still it would be cool to figure out a low tech system to make sure the “composted” material is plastic free.
And the other ones are more about the bioplastic and it’s process:
One on how to simplify the process of extracting chitin/chitosan from the shells, so that it’s doable in a non-Lab-setting.
And the other one on strenghtening the material I made so far by making it more water restistant, etc.
Maybe a bit off topic, but just wanted to open the door for your guys’ input and questions 🙂
Nice topic and thanks for sharing my homepage @donald! 🐛
These people in hawaii also do a lot of research towards composting Styrofoam with mealworms: http://livingearthsystems.com/mealworms-compost-styrofoam/
They also do a lot of other cool stuff, so check them out! 🙂
And speaking about a bigger worm: There actually is a bigger worm, that eats and digests styrofoam as well. They are called Zophoba morio and kind of look like a bigger version of the mealworm. (I think americans call them “Superworm”. Quite fitting in our case 😎)
I did a bunch of experiments with them in the beginning and they seemed to eat the stuff pretty well and definitely way faster then the mealworms. Just because I wanted to also make bioplastic from the chitin in the shells, I didn’t end up farming them, since their beetles can life for 15 years and I didn’t want to kill them. Or wait that long;)
hey @lucasvanvemde, we actually can’t send any samples out, since we are still in the research phase. If you want to, you are more than welcome to drop by in our workspace in Eindhoven though!
And if you have any specific questions about the properties of the material, feel free to ask them here or write me a message 🙂
And as @donald already mentioned: It’s always good to add yourself to the map, as you might also find like minded people around you, who could help you get started!
Oh and one more thing I’m still wondering how to do best: There is no pressure gauge on the hydraulic jack and it’s quite a messy process to put one in. (good example: https://www.youtube.com/watch?v=ZBmxkWK_OFA)
I already tested limiting the jack’s force by limiting the air compressors pressure. Testing the actual force in combination with the other press and it’s pressure gauge gave me pretty precise numbers on how much air pressure will lead to how much hydraulic pressure with the jack I’m using (e.g. 4.5 bar gave 8 tons with our jack). More over you could put in a pressure release valve in front of the hydraulic jack in case you don’t want to lower the main pressure on the compressor. So I could provide a table with a conversion rate for this exact jack and the air compressor I’m using, but I’m sceptical if a hack like this is a good (and safe) way or if it would be better to include the process of adding the gauge to the jack in the how-to for the press.
Ooooor maybe someone has a better idea on how to messure and limit the force in general? I’d love to get some more input on it 🙂
So I finished building the press yesterday. After cutting the big U-Profiles it was actually pretty easy to build the frame. I used a wooden sheet to keep everything aligned while I fixed the threaded rods and added some spring washers to make sure the nuts won’t move when I’m going to apply pressure. For the moving part on top of the jack, I welded some steel tube to the U-Profile (@pporg: yeah, I ended up welding anyhow 😉)
In general I’m a little unsure which direction is the best way to use the profiles in. My logic tells me, that it makes most sense to press agains the walls and not the bottom (like between the top profile and the moving part), but the more I think about it, the less sure I am. Maybe someone has some input on it?
Moreover I build a new version of the heating elements, which I want to connect permanently to the press, so we don’t have any cables on the mould and it’s easier to clean. Since it’s quite hard to find insulation material that doesn’t cave under all the pressure, I came up with the idea of insulating it with vertical plywood and use different heights to build air chambers. It might look a little complicated, but it actually wasn’t too much work, when you can cut stuff with the table saw. In general I’m wondering though, how much insulation really makes a difference in the end and if there isn’t an easier solution out there. If you have an idea, let me know! 🙂
So next I’ll add the heating elements to the press and see how everything behaves under 8 tons of pressure. Wish me luck! 💪
I’ll post an update about the progress of the press next, but to answer your questions first: @s2019 yes, it’s pretty much a hydraulic jack like the one at harborfreight. That’s the exact one we got: https://www.ebay.de/itm/163639580393
The one I chose is a little stronger, so I can actually test the limits of my frame at some point and also give some info of when it might break. Hopefully not too soon 😉
And about the rosin presses (from a pun-lover: props for the duckless duckweed pun ✊)
They also came up in my research and the heating is super nice to have, buuuut the work area is pretty small for most of them, so it would be hard to fit bigger moulds or objects. That’s why I decided to build one from scratch. Not to reinvent the wheel or anything like that 🙂
And @donald: The air pump of the jack works with a normal compressor at 8-9.5 bar. I also already tested a bit with limiting the pressure from the compressor to limit the pressure of the jack. But I’ll write more about it later on. But I’m super interested in the duckweed topic! Just started reading frogfalls paper. Did you manage to grow some in here in the Netherlands?
@huyennguyen: thanks for the links. super interesting! 🙂
About the compression machine: We tried using it in the beginning and it helped us quite a bit with testing our materials, but the pressure from it is not strong enough to make the materials really bind enough and spread throughout the mould. In the new press, that I’m developing right now (you can read more about it here), we can use much stronger forces, leading to way better material properties.
But the good news: the moulds in the videos look a lot like the ones we are developing, so hopefully soon, we’ll have a nice open-source solution for it 💪
And @msnmck: In this team we are only working with biodegradable materials and no plastic, so no, we didn’t make those bowls 😉
Hey there, sorry for the late replies. Somehow my notifications stopped working😒
@niting85: We posted the settings we found most useful for our machine over here!
And @chintu: Wow, that surface looks super nice! Would you be down to share a little more about the process you are using? And how you are getting the starch to foam that well? I would be super interested!
We are starting to go into different surface finishes, coatings and imprignations right now and will share more about it as soon as we found good stuff! 💪
@pporg thanks! You might be right about the drilling/welding part;)
But maybe being able to disassamble the press might also come in handy at some point.
And if you are down to share a few of your machine builder tips about the distances and how to turn it into a “pro” machine, I’d be very open to already let them go into the design right now!
So it was a bit quiet in our topic for the last weeks. (My last entry was at the end of February?! 😮) Time flies by, I guess 🦋…
In the mean time a few things changed, Marina went back to Finnland to finish her masters degree (Go Marina!💪) and I got some unexpected but wonderful support from @zsofi from Hungary. She is now testing out all kinds of different raw materials in our prototype in order to already build up a material library to go with the machine in the end. She will share the results of her experiments and all her fast growing knowledge in our materials topic soon!
On the other hand we worked on developing our proof-of-concept-heat-press further and are now far enough to feel confident to start the actual machine building. I will share all those processes from now in the machine development section of our topic 🙂
@s2019 Thanks for the Information!
And @andyn, that looks like a really nice and low tech setup! 🙂
I will definitely give the cartridge heaters a shot, as soon as I’m working on the machine again. The amount of energy used by the two hotplates was bugging me a bit already. Looking forward to the next version of your machine!
rice bran should be an option as well, even though we have not tried it yet. And you can find all the information we have so far in the linked forum topics.
If you have more detailed questions, send me a direct message.
@s2019, thanks for the suggestion!
I didn’t know about cartridge heaters, but it seems like a great option. When I started thinking about the heatable mould I was actually thinking about putting a hot wire into it, but it seemed like a lot of work, so I chose the hotplates instead. But these heaters look even easier.
How much heat do they create? How many do you use for your injection machine ( which looks amazing btw!!)?
Insulating the Mould
Insulation helps to keep the mould warm throughout the use. So far we have tried out three different ways:
– Bend metal sheets + stone/glass wool
– CNC cut wood covers with air pockets from MDF
– A low-tech version of the MDF one with wood covers and air pockets from coated plywood.
The combination of wood and air pockets inside seems to work very well, since it is apparently hard for the heat to go from a solid material into air and back into the material. But MDF is sensible to water and steam and starts to fall apart a little bit after a while (even though we covered it in paint), so it is important to choose something more waterrestistant like fir example coated plywood.
Designing a Mould
While trying out different mould shapes, materials and processes, we figured out a few rough guidelines on how to design a functional mould for biomaterials.
You can find and download our CAD/CAM files here.
– Slanted walls help the material to spread from the bottom of the mould up to the top. Thus it helps to put the walls at an angle lower than 90 degree, more towards 70/60 degrees.
– Round edges help to create an easier material flow throughout the mould.– Giving the bottom of the mould a slight angle and a center point also helps to avoid material getting stuck.
– Little details like embossed or engraved imprints transport quite well, while little sticking out parts (like the pins in the take-away-container) are weak and chip off very easily.
– Add L-Profiles or supporting walls, in order to keep long walls straight while the material is drying (like you can see on the sides of the take-away container)
If you are interested to find out more about our process until now and like reading blog-like entries, check out these two topics:
– Process of the Way to the Heatable Mould
– First Material Experiments and Way to Wheat Bran and Potato Peels