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Designs that do not fit in other categories. Previously named "New RepStraps and Post Mendel"
Impressive demonstration!
I wonder if the Epson piezzoelectric cartridges would work with UV-resins. They have the consistency of syrup, so maybe they would clog the very fine nozzles, what do you think?
Also, for this setup one could consider air drying resins, which should be easier to get by than UV photoinitiator mixes, although they are slower at catalyzing.
Another very easy option would be
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spota
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Powder Printing and Selective Laser Sintering
@Viktor
No worries, mate. i myself am extremely busy now, changing jobs as well, wich leaves me very little free time for much else. So, whenever you have time, have a go at the initiators I sent you and post it on the forum, as I will always be checking.
To bad about the silicone being UV opaque! That would really have been a great application. Did you see what happens if lightly heated? Maybe
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spota
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Polymer Working Group
Hello Nishant,
You can try Hydroquinone which should act as a radical blocker. Very low doses around 0.01% could be effective. Work upwards from that dose to increase potlife.
Do you know if your resin mix is sensitive to metal ions? If yes, adding EDTA would also reduce the sensitivity of the resin mix.
Good hunting!
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spota
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Polymer Working Group
Hey all!
@Viktor: I am very curious about what will happen with these catalyzers and the silicone resine. it would be a very interesting application if the same photoinitiators work. Please keep me posted on that!
As with the other idea you have, that's called live-polymerization. This is a very hot issue these days in polymerization chemistry. I'm a little green on that subject so I cannot tell
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spota
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Plastic Extruder Working Group
Holddd your horses, Zach!
Those links you sent me are for some really expensive stuff!
Here is a list of lamps with more reasonable prices:
Here's an online shop with the germicidal kind:
Click on the GERMICIDAL - COMPACT FLUORESCENT (can't link directly here)
And under ULTRAVIOLET - BLACKLIGHT BL350 - FLY KILLER they have the blacklight model.
Actually I got mine from a regular lighting shop
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spota
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Plastic Extruder Working Group
I understand. I'm not so familiar with FDM printing strategies, but I do get from your explanation why grip is important. And I agree that the best candidate for support material in that case is the same polymer.
Maybe a combined approach to the support role could be applied: use agar or similar for the gravity support material and columns of polymer for specific points where grip and warp avoid
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spota
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Plastic Extruder Working Group
That much?
That's quite a tall bill! What you are looking for is a remedy to shrinkage, I don't know if any support material can give you that. Bodies, when cooled down will try to shrink. If you don't let them, which requires some serious tension bearing devices, they will become tensioned. IMHO, a "sticky" surface is just not a good enough device to maintain and counteract the tension created i
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spota
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Plastic Extruder Working Group
On the bacteria issue, adding some antiseptic to the mix would also do the trick, like soap or bleach.
I only tried with PP over the agar. It stuck very lightly, indeed, but not enough to require heavy force to remove it when cold. The question being: how much would it be necessary to stick?
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spota
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Plastic Extruder Working Group
Melting the gel in the microwave is very easy!
It also accepts a lot of fillers. So far, sand-dust or clay dust have had the best results in respect of adding better mechanical stability and thermal resilience to fused polypropylene.
I think this stuff really is ideal as support material for the FDM process.
The only point to be solved is how to deposit it, be it by creating 3mm rods solid enou
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spota
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Plastic Extruder Working Group
Yeah color is such a great plus.... today I have been dreaming of printing a new body for my glasses. I just grew tired of the ones I have and thought how cool it would be to have many different sets to juts wear for whatever mood you have.
Ok, so here are the first results!
A mix of 2g Agar Agar with 100g of water results, once cooled down, in a rubbery gel, quite more stiff than regular Gelat
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spota
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Plastic Extruder Working Group
Adding color would be very easy indeed, like easy to get food colorants.
I'm currently making some tests in my kitchen, keep posted, in 10 minutes I'll have some thrilling updates!
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spota
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Plastic Extruder Working Group
Ok, my curiosity was such that on the way home I went to a nutrition shop and got me 200g of Agar Agar for 11
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spota
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Plastic Extruder Working Group
I have thought for a while about a cheap and easy to use support material that might be used. There have been several materials proposed but my approach to this is that it should be as easy to obtain and prepare as possible, as well as easy to work around and remove once the piece is finished.
Also, being non-toxic would be a plus.
The first thing that came into my mind was Gelatin, but It has t
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spota
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Plastic Extruder Working Group
Wellcome back Mike!
As of lately I have been very busy with stuff unrelated to RepRap. I'm trying to get my ass back to R&D at work, wich takes a lot of my time.
The only developpement I have been able to keep up and finalize is the UV-curing resins, the results which you can find in the Fabrication forum.
As for the Furfuryl Alcohol/Furfural resins, I have no new developpments yet. I have
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spota
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Polymer Working Group
@nathan:
I have tried out the upper UV-catalyzers with rectified linseed oil I got from an art-shop and it didn't work out. Looks like the double bonds available in the linseed are not available to the radicals created by the above catalyzers. sorry...
@viktor
In some other posts abouy phenolic resins i was trying out an organic acidic solid, solved in ethanol, called Tolueneparasulfonicacid tha
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spota
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Plastic Extruder Working Group
Hello Nathan!
There seems to be a real lack of online sites that sell an of-the-shelve acrylic casting resin. I have been looking for it for over an hour now and have found nothing that would be usable.
If I recall well, there was a page i found some time ago that talked about a MMA (methylmethacrylate) and BMA (butyl methacrylate) mix that was used to produce glass clear castings of objects. You
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spota
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Plastic Extruder Working Group
It really depends on what material you are using.
If you use spontaneous or triggered catalyzer hardening resins, you can apply many different types of building strategies.
Stopping and restarting in the middle of a printout is just one. Another that comes to my mind is to print out compartments, later to be filled out with casting resin.
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spota
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Plastic Extruder Working Group
@Paul:
Here a couple of sites for epoxy resins I have found online:
@Adrian: All of the shelve UV-resins you will find are hugely expensive. Refer to the post above if you want to have a cheap version that you can mix yourself and are between 10 to 100 times cheaper (sometimes 1000 times cheaper for rapid prototyping mixes, they are really ripping people off)
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spota
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Plastic Extruder Working Group
What about creating a light underpressure in an airtight volume to accelerate evaporation?
I envision some kind of a vacuum pump sucking air out of the reprap and condensing/recycling/disposing the solvent out of the air.
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spota
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Polymer Working Group
It could be usefull if we solve some major problems: the bubble formation of evaporating solvents and to get the evaporation to be uniform. Also, we need to get rid of all the acetone from the room, so ventilation will be necessary. It would be desirable to remove all the acetone in the mix to get a solid body. This would probably shrink the printed layer in some way, as we reduce the volume of e
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spota
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Polymer Working Group
Great! I'm curious about other resins too. Will get me some epoxy soon.
Yeah I read upon the polystyrene and acetone, I will type an answer in the other thread now.
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spota
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Plastic Extruder Working Group
OK, no problem! Whenever you have time.
I also guess the mechanical dispenser is probably easier to build and maintain, as well as cheaper. Will you be using Polyester or Epoxy resin?
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spota
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Plastic Extruder Working Group
I discovered by keeping the resin mixes in the dark that the pot-life they have is mainly dependent on light exposure. For three weeks I have had a mix isolated from light and it hasn't changed in any way. Good news, as keeping the resin unexposed to light until usage is pretty easy to achieve.
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spota
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Plastic Extruder Working Group
I think there is a previous thread on this issue in these forums. Dunno if a search will pop it up.
Bottom line is that it's not easy to synthesize, it's more of a factory process.
Check out this for a hunch:
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spota
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Plastic Extruder Working Group
What's the brand of this conductive paint you are talking about? Is it available in shops or online? if we can get a conductive path painted with this and improve conductivity by electrolytic deposition of copper this would be the easiest solution.
I have made some conductive resins loaded with copper powder filler, but the resistance was in the order of 1 Ohm, which is to much for circuit board
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spota
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Plastic Extruder Working Group
Yup, that's great!
I somehow wanted to have everything together in one place.
Before you start mixing away with the chemicals I sent you, we should first discuss it here. I am sure the mixes I mentioned above can be made more economical, like 3g+3g+1.5g or such.
One question for you: do you have access to a chemical products store next to where you live?
You will notice pretty fast that once you
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spota
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Plastic Extruder Working Group
Well the only ways i know of to reduce Copper 2+ to elementary copper is eitjer by electrolysis or by deposition on a less noble metal, as zinc, iron etc. deposition usually results in an uneven porous surface that won't conduct well. As for ascorbic acid, or any reducing agent, you will most likely only be able to reduce Copper sulfate only to its Copper 1+ form, just a different salt, really.
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spota
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Plastic Extruder Working Group
4) Recipes
Here I will list a number of possible recipes for UV-curable resins.
The list below is just a start and I'm sure a wild variety of different ones will emerge and evolve in time. I have created a small spreadsheet to calculate the prices of these mixes. I will show the price as well. Pot-life of all these resins can greatly be improved if they are kept away in dark places and in opaque
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spota
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Plastic Extruder Working Group
3) UV lamps
Here I will discuss the source of UV lights that can be used for curing the resins at hand.
The wavelength necessary for activating the photoinitiators is dependent on the chemical nature of each photoinitiator.
In our case, Benzophenone, Benzil and Benzoinisobutylether are all especially sensible to 2 wavelengths: 256nm and 365nm.
256nm UV-light is in the UV range generally describ
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spota
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Plastic Extruder Working Group
2) Catalyzer Chemicals
These are the names of the chemicals used:
Benzophenone, CAS: 119-61-9 (+/- 44Euro kg)
Benzil, CAS: 134-81-6 (35Euro 500g)
Benzoilisobutylether, CAS: 22499-12-3 (36Euro 100g)
MDEA, CAS: 105-59-9 (31Euro 1kg)
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spota
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Plastic Extruder Working Group