I am starting the mold making process for the Darwin parts. Omega was good enough to email sliced images at the correct dimensions for paper laminating. The question is what order would the group like to see the parts made in. Its going to take quite a lot of time to build the inital molds so I want make parts that would otherwise have to be made by FDM. Mike The thoughts and ideas expressed inby ohiomike - General
Sorry about the wait, the files were exactly what I was looking for. Now its just a matter of the time to start making molds. I will try and start on them this weekend when I get a couple of hours to work without interruption. Mikeby ohiomike - General
Excellent work! One of your major issues is likley purity. A garden fungicide likley has stablizers and other components. These are plating out along with everything else. Have you attempted to add a small amount of sulfuric to the bath, that usally increases plating thickness. And of course a larger power supply would also speed the process. Assuming that you cant find a cheap source of copperby ohiomike - Polymer Working Group
I suppose Fernando and myself are the current big pushers for thermoset type systems. I am a chemist working with one of the major producers of those types of systems so its what got me involved in reprap in the first place. I have access to literally hundreds of different types and varities of resins. As well as having access to the PhDs that developed them. I am currently experimenting with aby ohiomike - Polymer Working Group
I'm not at work right now (the files are on my work computer) but expect an email in the next couple of days. Both positives and negatives would be appreciated since I may end up making disposable molds from a laminated positive for resin based investment casting. Or maybe I'll do a resin casting of a negative mold from a laminated postive and burn off the paper at 300C or so. I suspect I will bby ohiomike - General
The easiest way would be to use a cookie sheet with fairly high sides, telfon lined being ideal. The put a known weight of ground plastic in it and shove it into an oven set at about 300F, well above melting but not hot engough to ignite. Then periodically pull out the sheet and use a marble rolling pin to weld the pieces together and smooth them out. At a known surface area the weight of materiaby ohiomike - General
Thats basically the way it is. You can either do it by stretching/compressing or chemicaly by changing the level of very linear sections (not suprising called plastiziers) or hightly branched sections (crosslinkers) thats the difference between PVC and CPVC the C stands for crosslinked. Crosslinked materials have more heat and stress resistance and so are tougher materials in general but also farby ohiomike - General
Thats great to hear, when I contacted them they had not been able to locate them. Mikeby ohiomike - General
Sorry guys, I hadnt realized you were looking at that stratasys system. I contacted Stratasys and the software for that model is no longer sold. Meaning that we would first have to locate a source for the software before purchasing the system would make sense. Thats very common since the 3d printer manufactures want to prevent the sale of used systems. Something else I have been considering wasby ohiomike - General
I was mistaken about the volumes, I had thought that the quotes were for just the materials not for a commercial printouts. My next thought was that based on conversations and websearches I have located a manual 3d printing system, RapidPro, that takes a STL cross sections it and plots it on a vinyl cutting machine. RapidPro costs $900 and a basic automatic vinyl cutter costs $400. Assuming 50%by ohiomike - General
Correction, I forgot to move the decimal. The 1-5% range of addition would add $0.06-0.30/lbs. That makes a huge difference in material usability. Mike The thoughts and ideas expressed in this post do not reflect those of my employer and are intended only as communications between individuals. Any attempts at implement are at your own riskby ohiomike - General
I did a real quick look around to see what was available, since that internship was most of a decade ago. Quite frankly the dozen I was aware of have exploded into a hundred or more. Is describing a relativly low tempature decoupling vinyl protecting group on a carboxcylic acid catayst for an EPOXY, which would potentially give us extremely high strengths and/or potential filler loads. As farby ohiomike - General
Just some more random thoughts on chemical/material elements of the process. I know that with lasers a lot of the cost is the photoiniators, but polymers that can be cataysted by free radical type reactions arent really that cheap to begin with. That led me to thinking about some work I did on an internship in college. The coil coating industry (sheetmetal coatings, appliances, lighting fixturesby ohiomike - General
Debugging seems to be the major issue right now with those systems that are up and running. I am really of no help with software or electronic issues but I was wondering what tests each builder has found most useful. I am thinking about the eventual creation of standarized tests, for example cone sag comes to mind where you could print out hollow cones of various base diameter, then measure theby ohiomike - General
I must admit that I understood about 60% of that. I can write the smallest amount of virtual basic, and that makes me a software guru among material scientists. But I get the gist, that it is possible to modify the existing code so that you can take a STL file and output a pile of GIFs or PBMs rather than sending it to the robot. That might make an interesting way to eventually test the tolerancby ohiomike - General
It really depends on the dimensional accuracy requirements of you finished repstrap. Not to mention that you can always build slightly large and sand the finished material to whatever level of accruacy you desire. Ideally you would be able to quickly build those parts that dont require high tolerance and then make priority decisions about the others. And of course nothing says you have to buildby ohiomike - General
I have often found that if you really want ideas about efficent material handling, you should look at textiles. Clothing manufactures have some of the most ingeinus ideas about how to make 3d objects out of basically 2d materials. I strongly recommend that if you have never taken a basic sewing class that you do so, the little tricks that people have come up with are based on on very subtle underby ohiomike - General
Mute point, the auction was cancelled. Mikeby ohiomike - General
My understanding is that it is an inkjet design with the material in a cartrige and the UV source riding next to the nozzle. My issue is that if I over or underdo the viscosity or cure speed the result will be a clogged nozzle, which might rank anywhere from a minor annoyance to a major issue. I am simply to unfamiliar with the machine to guess. Partially cured resin would likley just need to beby ohiomike - General
Dont know what this particular model cost orginally but the same level of machine today goes for $16K. I got a demo model offered to me for $12K during my search. This is the most basic of systems, anything more advanced jumps in cost to $40-$60K. Although I should say I got a functioning Stratasys 1600 offered for $3K but without software. I contacted Stratasys and they said they no longer suppby ohiomike - General
the object library reads like a cheap spam message, someone hacked it and turned it into a list of links to pharma-spam. Mikeby ohiomike - General
While researching hardware I noticed that paper lamination is a method of 3d modeling. This got me thinking. If it were possible to print cross-sections of a STL file onto stock paper then cut and paste (literally!) the sections together you would have a rough form of a part. That might be enough to allow impregnation, resin casting, or more importantly the casting of a negative mold. If I can fby ohiomike - General
Its an Invision Si-2, the seller is a couple of hours drive North of me. I contacted 3d systems (you would be amazed how helpful people are when you call from a billion dollar corporation) and they quoted me $5 per in^3 ($0.32/cc) for the cartridges. How does this compare to the cost elsewhere? The salesman was trying to point me towards a more advanced system ($60K to start) and suggested thby ohiomike - General
For me its one of the back burner projects, simply too advanced to worry about at this stage. IMO, it ranks behind getting wiring and electronics into the build, but not very far behind. Mike The thoughts and ideas expressed in this post do not reflect those of my employer and are intended only as communications between individuals. Any attempts at implement are at your own riskby ohiomike - General
You can buy copper sulfate as a fungicide at farm supply stores, and at larger hardware stores. Its mostly used in farm ponds. I did copper plating as a science fair project in junior high, and didnt bother to mix at all, I just used a saturated solution. If mixing becomes an issue the sulfate isnt going to hurt a simple aquarium pump. I used a car battery and it took about 5 minutes to get aby ohiomike - General
I was thinking the exact same thing, similar to my experiments with drywall compound where the extruded material is only suppling a form to contain the casting resin. Maybe design gates in the infill so that the casting resin can join up with inself throughout the finished part and the thermoplastic would only act as structural reinforcement. Of course that leads to all sorts of interesting ideaby ohiomike - General
You rang? I too have been experimenting with epoxies but not so much the UV versions as the composite versions. My employer has a toll-production setup with a line of Huntsmen's structural adhesives that have a selection of activators, 45min, 60mins and 90mins, if memory serves. I imagine the activators are syrene/peroxide blends although I dont recall off-hand. With those at least I am not soby ohiomike - Polymer Working Group
I suppose extruder was the wrong word for me to have used. My equipment is quite different from the normal reprap. I am using a air-powered binary polymer gun as a "3d pen" to test chemical compositions. So my gun can push fairly heavy filler loads though a static mixer to get a testable result. My image of the final product was a progressive fill cavity with the inorganic filler mix and printinby ohiomike - General
My thinking was also revolving around the money issue, grad students and university departments have access to grant money that private non-profits cant access. Mike The thoughts and ideas expressed in this post do not reflect those of my employer and are intended only as communications between individuals. Any attempts at implement are at your own riskby ohiomike - General
After speaking to the head of the Fab@Home project at Cornell, an idea occurred to me (and I never met an idea I could resist). Reprap might benifit from asking around local univeristies to see if any of the material/engineering departments might be interested in getting involved. I work very near to the Ohio State University, home of an excellent materials science department. Being Alumni I seby ohiomike - General