Ugh... today seems to be the day of bad news... Sorry to hear about your hand. Take care, health goes first! You are right about after curing with 405nm. What power do the LEDs have? After-curing is generally a quite extreme process, while keeping the exothermics of the reaction in check.by spota - Polymer Working Group
Leakage!?? Damn!! Those bottles are not worth the price I paid for them!! Did you loose a lot? I am so sorry to hear that... Here is the breakdown about your samples: SR499: very reactive, fast curing, low viscosity resin CN2302: intermediate reactivity, medium viscosity, high resolution and toughness/impact resistance SR601E: lowest reactivity, highest viscosity, toughness All three resins arby spota - Polymer Working Group
I have been discussing with Viktor (VDX) some of the details of the Visible/Near UV light polymerizing resins that i'm sending him. As we were responding through a series of private messages, we realised that this info was better to be found in the public forum, so here it goes: Spota: I have prepared the smaples with the H-Nu470 PI, let's see how this works with 445nm What is the experiment youby spota - Polymer Working Group
Heheh, yeah spota=spacecaptain=Fernando, I have been uncovered As for approving new users, that would have to be done by the list owner, and I do not exactly know who it is. Isn't there a way to PM or email him directly so that he knows you have joined? Maybe he has a look at inscriptions only from time to time... I would rather the whole group migrated to a forum as the one here on RepRap, Iby spota - Polymer Working Group
Well, your setup is a little more powerful than mine, so several of the resins I test should be fine for you. You may go a little more intense but it is not really necessary.by spota - Polymer Working Group
Interesting. You plan on leaving the projector unmodified? The higher the irradiance (watts/area), the faster your setup can cure the same resin. Or in other words, at a constant cure interval, the less reactive the resin needs to be. There is no simple relation between ANSI Lumens and irradiance, but if you tell me the Lumens your machine produces I could make an educated guess at what resin woby spota - Polymer Working Group
@B9Creations Yes, that would be the place where I post my results. I am currently quite busy preparing samples to send out and coordinating providers and materials, evaluating the resin feasibility. This is why lately I have not posted much new stuff in the wiki. I am also participating in a diy email list which discusses details of 3D printing in general. But I always keep an eye on what's beiby spota - Polymer Working Group
Well then I think you or your college should definitely give my resins a try! I am currently making a list of resins that I have to send out to people. None of my current contacts is going to use the setup you mention with 445nm and I am very interested in being able to get some results on that. So, should I get you 50g of several candidates with different cure speeds to see which one works bestby spota - Polymer Working Group
Ughh, had forgotten about that one! It was UV curable Polyester resin right? That's all quite old fashioned and a rather non-functional solution compared to what I am using now. I am working with very reactive acrylic systems and better Photoinitiators that allow us to work in the visible spectrum and with a lot less irradiance power. I would have to send you these new resin systems. But if youby spota - Polymer Working Group
Hello Viktor! If you take a look here [3dprinter.wikidot.com] you will see that I used Photoinitiators that work in diverse visible light ranges. I have a sample of H-Nu470 available that could be tested against blue laser setups. In the tests with H-Nu470 I have conducted so far I found this PI to be quite intensity hungry the higher you get in your wavelength, the best results being achieved iby spota - Polymer Working Group
@jdoggy72, Kaare et al. I am in the process of testing my own formulated resins on real DIY DLP printer setups. Contact me if you are interested in samples (as long as I have test resin available). If these tests go well (prospects look very encouraging), I will look into providing my resins commercially at a reasonable price, if it makes economic sense. If I can't provide at good prices it woulby spota - Polymer Working Group
Hello Kaare! I sent you an email. Check it outby spota - Polymer Working Group
Well this is exactly how I imagine the "market" will be. There will be a "long tail" of users that need small quantities of the resin. And those users need a place where they can get that amount of resin without having to spend $2000 for a pail of it that they won't use in years. You are right about the very high resolution: we can currently start at 0,05mm voxel resolution. I am considering waby spota - Polymer Working Group
Hey Viktor! Nice to encounter some friendly faces over here again! You seem to have an interesting setup. The LEDs you are using, if collimated enough may very well work with the formulations I am thinking of delivering. Each will work with a different one, as I will be using two different Photoinitatiors. I'm currently documenting my work over at [3dprinter.wikidot.com] When I find some time Iby spota - Polymer Working Group
Hello RepRappers! It's been a long time since I posted here and I am coming back with some results and a question to the community: I have been researching within another 3D printer group on resins to be activated with regular visible light in the blue spectrum range, together with some near UV. This is the spectrum emitted by regular halogen lights form DLP projectors and also some unprotectedby spota - Polymer Working Group
Expensive. I have seen quotes for 1,6-Hexanediol diacrylate at 93€ for 500g and for Phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide I have seen 42€ for 10g. If you are looking for UV applications at lower wavelengths there are cheaper mixes. If you want to use the close to visible spectrum, those are the expenses you will typically be looking at.by spota - Polymer Working Group
Well IR spectroscopy is not as easy as shining some unknown IR source and recording an image on a receptor. Thinking of the things you need to build a DIY IR spectrometer is somewhat humbling: You'd have to calibrate your IR source. You can shine this IR source, record the baseline emission, then introduce the sample, record this transmission and substract the baseline emission. Then you have toby spota - Polymer Working Group
wow... ok, good you told me, I think its the euro sign that makes it freak out then! I will edit the post right away. BTW, nice to see you !by spota - Plastic Extruder Working Group
Oh so neat... Somebody with writing credentials, acquired or hacked, has deleted the info on the chemicals post (Nº3). I guess it's about time I get the info from this thread somewhere else, as I have the feeling this topic is not welcome here. Sorry, i was being paranoïd! It seems to be a bug that doesn't like special characters (Euro sign made it freak out and delite everything that followed.)by spota - Plastic Extruder Working Group
Mike B Wrote: ------------------------------------------------------- > That's about $15 per pound. A 24v 20ah battery > weighs 10 pounds. But I believe that weight is > made up mostly by two solid doped polyethylene > electrolytes. So I really can't see how the high > cost of these batteries (hundreds of dolloars) is > justified. Depends on how the doping process is done. Aby spota - General
mycroftxxx Wrote: ------------------------------------------------------- > No, no blogging yet. I guess we'll have to start > one. And do some photography. So far, there > isn't much to see. Materials consist of a > cardboard box containing parts from a Dell 720 and > a scanner. Otherwise, most of the work has been > done on pen and paper or in folk's heads. We will >by spota - Powder Printing and Selective Laser Sintering
@Viktor: Okay, so you will have to play around with the light source. Probably, a near UV would give the best results? Maybe blue light? Shrinkage is bad, indeed. Maybe a drop is to thick though to make a test. try this: put one thin layer, harden it, and repeat with a couple more layers and see if you get weird deformations due to shrinkage.by spota - Polymer Working Group
Well, it's one provider more to add to the list. Nevertheless don't expect their products to be cheapby spota - Polymer Working Group
VDX Wrote: ------------------------------------------------------- > Hi Fernando, > > ... now, after nearly an hour of testing it seems > to be clear - small blobs of Acrifix (maybe 1mm > diameter, 0,4 high) are complete hardened after 20 > minutes UV-radiating with the 4W-tube from 30mm > distance. > ... > > So you need much more power for hardening in > seconby spota - Polymer Working Group
I agree. You need to know the curing wavelength of the acrylic mix. You could be irradiating it all day long, if it doesn't match the correct wavelength for you photoinitiator, you won't get the desired results. It's all about quantum mechanics: intensity is not enoug, you have to use the right energy quantums (read, wavelength). Don't the specs of the product come with some info on that? They reby spota - Polymer Working Group
Interesting! That's actually slower than I was expecting. I suppose the concentration of photoinitiator is lower than what I use. On the other hand, you are using lamps that are 10% as powerful as the ones I use. I'm pretty positive that if you were using 36 or 40W lamps as I am, this would all harden a lot faster.by spota - Polymer Working Group
There's nothing wrong with it at all, apart from it's volatility and flammability. I think it's a very interesting candidate and I'm currently working on it. It will work with similar photoinitiators as I mentioned in another thread and you could reduce it's volatility by adding polymethyl metacrylate powder to it, basically filing residue from PMMA cutters. MMA would actually be one of the bestby spota - Polymer Working Group
Yeah we want to be able to do finshed parts as well as molds. Both things are a very good thing to be able to build. The strength of the dry product is impressive, if in layers we can achieve half or a third of that i would be more than happy. You can always add extra toughness afterwards with very cheap resins. The end result should be very resilient indeed! I think the only issue here may be iby spota - Powder Printing and Selective Laser Sintering
Yes dental UV-resins are extremely efficient acrylic polymers that activate in the near UV/blue wavelengths. The problem with these mixes is their very high prices. The aim of what I did here was to device a cheap and standardized solution, for prices around 20$ a kg of resin with all the elements included.by spota - Polymer Working Group
Sounds good. Seems like they are using some fancy photoinitiators if they work with near UV, henece the price of the product. It may be interesting to know what times you need to completely harden a 3-5mm film with the EPROM erasing UV. Imagine this would be like a 3 to 5 thick layers worth of resin and it's a good benchmark. As a comparison, my mixes set within 7 minutes and completely hardenedby spota - Polymer Working Group