Wow it feels great to be back! Wonderful to see that you have kept after this side of things. Since the Furfuryl reaction is a dehydration reaction one of the easiest ways to slow things down is to add a little water or even a mild base since when the blocking agent comes off of the catayst the resultant acid will be bufffered. That allows you to not starve the individual areas of the build whiby ohiomike - Paste Extrusion Working Group
Its been suggested from time to time. Somewhere in the archive there is a project where copper flake was added to a resin and the mixture extruded onto a plate before being used as the cathode in a copper plating bath. The drop in resistance was impressive so it is do able but adhesion promoters in electroplating are fairly complex things and would need a lot of work. Mikeby ohiomike - General
Hello all, Long time away due to job changes, spousal health issues, blah, blah, blah. Long story short, I no longer work for the employer that had issues with my reprap work. But I have reconnected with several former clients, one of which is interested in reprap. I have been looking to get a copy of the laser cutting file in a DWG or a EXF format since that is what their laser cutter uses asby ohiomike - General
There is a reason behind this, my understanding is that if a term is a recognized "generic" term for something it can't be copyrighted, at least in the US. Since we are a non-profit group talking on an internet forum they couldnt stop us from using the term if they wanted to, all they can do is ask. They are asking because if we do continue to use the term as a generic then they will have a muby ohiomike - General
This is one of the major advantages of Reprap that most have overlooked. The core system is great for artists and for hobbists and will maintain a major focus on versitility. But for more serious applications there exists the possibility of making specialized reprap like robots that are not in fact repraps. Take your liquid transfer system as one example. Add a second arm that transports a loaby ohiomike - General
I dont suspect that they will change the legality of an individual purchasing it. But it will change the number of companies willing to supply it. I dont suspect the price will change much since there will be a glut in capacity for at least a while. Mikeby ohiomike - Polymer Working Group
Hemi-cellulose actually, which is present at some level in all forms of cellulose based plant life. As a rule 10% by weight of any cellulose based material can be converted to Furfural. The best sources are oat hulls (which is why Quaker Oats makes the stuff), and corn cobs. Strangely enought hemi-cellulose is actually a major component of algea cell walls so algea based biodiesel and corn baseby ohiomike - Polymer Working Group
At least for the time being PLA is likely to be more popular then a lot of the other biopolymers for the simple reason that it is a biobased thermoplastic which is not that terribly common. Furfural Aldehyde is a biobased thermoSET used in the foundry industry. Its relativily simple to make, being an acidic distillation of hemi-cellulose. Quaker Oats is the only producer of it in the US and theby ohiomike - Polymer Working Group
Hi all, Been gone for a while, on the plus side I have managed to file my first patent application. Hoping to get back involved in the coming months. Whats the status on chemical issues? Any news on Furfural Alcohol as a build material. I need to let you guys know that it will likley be declared toxic in the EU in the next 2-4 years. That doesnt mean its any more (or less) dangerous than it haby ohiomike - Polymer Working Group
Try mixing the catalyzer into the flour first, partially fill a pan with the resultant mixture, and then using a syringe write a pattern in the pan with FA, add another layer and repeat. I would be very interested to see if you have any interlayer adhesion issues and what your surface finish is like on the finished piece.by ohiomike - Paste Extrusion Working Group
Heat-Shrinking Polymers are really cool stuff. They are kind of in the middle between thermosets (like Furfural) and thermoplastics(like the filiment we are currently using). Actually I suggested some time ago that we look at crosslinkable thermoplastics (the things that you need to form heat shrinks) since they would allow us to extrude as a thermoplastic, recycle any mistakes/low tempature usby ohiomike - General
I contacted them some time ago and basically got a shrug. They have the same problem that we do, too few systems in operation. The grad students running the project cant turn a profit with university resources. No one else was interested in helping us make parts even with the offer of payment. Mikeby ohiomike - General
I am insuffiently familiar with the software and firmware concerns to really judge what is easier. If having a ribbon like pattern removes the necessity for a support material extruder because curves can be built "igloo" style, then it might be easier to have a stepper motor attached to the nozzle mount to control the ribbons position rather than add another extuder. That was the point of the sugby ohiomike - General
In a recent post I make a offhand comment about using pressure nozzles. But it occurs to me thats not that bad an idea. Cake decorating nozzles are stainless steel and built to be easily interchangeable. Its possible that using a slightly star shaped nozzle would increase interlayer adhesion since the bottom layer would have a much higher coeffient of friction even when the top layer was completeby ohiomike - General
Use it make molds rather than the parts themselves. Make the extruder out of a thermoset (or even alumium) and heat the thing to a much higher temp so that the plastic practically flows in a continous stream. Use a thicker filiment and then a pressure nozzle to force the material out at a higher rate. Frankly you could do what they do in cake decorating and make the nozzle changeable so that yby ohiomike - General
A major issue with fibers is that they are resin hungry materials. If you want flex in the material add polyurathanes. Most two part polyurathene casting resins sold at craft stores are straight chain polyols so they have relatively high molecular weights to hydroxide values. The furfural with react with the polyol so you wont even have to use the isocyanate. Also detergents or soaps are goingby ohiomike - Polymer Working Group
Most of my work is development not true research. Research is always years ahead of the development that MIGHT make it cost effective. Reprap is potentially a developers dream in that would allow you to run constant small variations and completely plot out the cause effect graph in more dimensions than we can hope to do now. I am a half-way decent statistician and I usally stick to no more thanby ohiomike - Polymer Working Group
Interesting, although there doesnt seem any reason to stick to solely support materials. You could make the bath a polyol and then extrude liquid hardener into it, making a quick and dirty (and I mean really DIRTY) protoyper with no need for support mateial and the ability to build in X Y and Z at the same time. Mike The views expressed in this post is not that of my employer. Attempts at impby ohiomike - General
Thats all it is the trick as you say is in the vials not in the machine. As far as research is concerned Reprap's strength is that it would allow for the inexpensive expansion of a lot of testing. Currently in research one major limitation is that you can run many factors at the same time since the number of tests inceases geometrically. But comparing factors run seperatly means that you missby ohiomike - Polymer Working Group
I started this thread to comment on the cookie extruder and of course had three ideas come into my head while composing it. The cookie extruder is a interesting application, I could see a basic food reprap being an interesting sideline to help push the bulk of the research. I suggest you go have a look at it, but onto the main point of this post. Nophead, I dont think its the conductivity of theby ohiomike - Reprappers
WOW! I'm VERY, VERY glad you were only working with 10g at the time. Explosive polymerization is a very accurate term for what happens, isnt it. That you were working with a sealed jar is quite scary. Whats the pot life like for the blocked catayst/resin mixture. Is the resin advancing due to the presence of small amounts of unblocked catayst? If you are using inorganic fillers you might consiby ohiomike - Paste Extrusion Working Group
Sterlings require very tight fitting seals to be efficient. A fluidyne might be possible however, since that uses a fluid to generate a perfect seal. But fluidynes dont generate much power, and one made out of plastic is going to be solar only as the heat source which further reduces max power output. A large enough one would certainly work but what would be involved I can only guess. A furfuralby ohiomike - General
I have recommended some of my employers products (because I developed some of them), which no one there really had an issue with. The problem was that when I was brainstorming on ways to do things I also suggested off label uses for some of those products. Now I have always been sure to say be careful but not always been clear on stating this is only guess work and attempt at your own risk. I haby ohiomike - General
My boss recently read my postings on the blog and pointed out that I should make it clear to anyone and everyone that the thoughts and ideas expressed are my own, not those of my employer and that attempts to actually try any of my ideas are at your own risk. All communications from me are intended as communications between individuals and have no connection to my employer. Mikeby ohiomike - General
Interesting post, it highlights quite well the differences between two major camps in this group. The pragmatists and the dreamers for lack of a better way to describe them. Your CNC sounds wonderful, I would be very interested in seeing how you built it. A couple of evenings of work giving a repstrap would be amazing. But I am definitly a member of the dreamers camp, so I think you are wrongby ohiomike - General
The issue of clothwork and knitting have come up a couple of times so I will put my bit in. My wife is a seamstress and I am a semi-skilled knitter. I have tried in the past to knit thin gauge wire, the problem is that raw wire doesnt bend nor give very easily. If you were to use a spool on thin braided and insulated copper wire (speaker wire would be a good example of what I am thinking of) in aby ohiomike - General
For me "wealth without money" is a statement of purpose, a declaration of independence. It comes with the understanding that you are approaching it as a limit not as an actual goal. Its a motto and like a lot of mottos is hyperbole, when someone says "Scotland Forever" you would look like a fool if you started talking about the heat death of the universe. It declares our priorities honestly andby ohiomike - General
Its mostly about what MIGHT be possible, this is afterall a research project. Personally I imagine small scale production facilities popping up around the country, similar to the old town blacksmiths. A lot of country farms had a basic forge onsite but took more difficult jobs to a local blacksmith. In the foundry business these are called job shops and their are generally a lot of them aroundby ohiomike - General
I am attaching a copy of the email I got from rapid pro. A commercial software package costs $1595 and the cheapest I have found the 24" cutter was $700. Thats $2300 for a NEW manual rapid prototyper. Assuming 100% material usage the cost per in^3 was $0.10 but of course we might get a quarter of that considering this is an reductive prototyper not an additive one. Still at 50in^3 and assuming 2by ohiomike - General
A lot of the issue is that they dont have many more systems running than we do. I have been trying to get in contact with them again to set up a proof of concept printing of some parts but so far no responce. I am hoping that this is just because of the summer break but I will try again in a month or so and see what happens. Mike The thoughts and ideas expressed in this post do not reflect thosby ohiomike - General