SLS Printer
This page describes attempts to build a Selective Laser Sintering (SLS) based 3D printer, using as many inexpensive and off-the-shelf components as possible.
description = documenting the development of a simple selective laser sintering 3D printer | license = GPL | author = Peter Jansen | reprap = ? | categories = SLS Laser Powder
} Create your new page by logging in, editing the URL of any wiki page, and then clicking "edit". Please use this page as a model, or copy. You can get the "mediawiki text" by clicking "edit" on this page. This page represents an example development page and showcases many features that can be used in creating new development pages. ContentsWorking Notes. This is a stub!Everything below this point is working notes. first tests building a powder-based stereolithography printer: part 1 hi folks, i'm a bit sleepy, but i thought i'd post this while it's fresh: after seeing really interesting powder-based printer designs like this one, that place down a layer of powder then "print" a binding material onto it, i began to wonder (as others have) if we could build a similar setup using ABS powder and a laser diode to fuse the material together. designs like this have a bunch of benefits, including the potential to use the powder as it's own support material. (and, after a few weeks of tinkering with building an extruder for a second printer that *constantly* clogs, i think i needed a break to think about better days when we won't need to rebuild extruders, or hope we build working ones in the first place... ). my goals for this tinkering are to build things with common off-the-shelf materials wherever possible, and so I went searching for some form of ABS powder, as well as a laser diode. After some searching, it looks like ABS powder really isn't easy to come by, and it's most often found in pellet form. Zach had a similar idea a while back ( link ), and so I asked him if he'd had any luck. He said he never got past the materials research stage, but that polyester-based powders used as powder coatings sounded promising since ABS powder was so hard to come by. I figured that if I was going to use a DVD burner laser, I'd need some black powder to absorb the radiation (since a 250mw red laser is relatively low power to melt plastic that isn't black). I sent an email to our local hackerspace in hamilton, thinkhaus, and folks were really encouraged by the idea. One of the folks there, jason, ended up finding a local place that manufactures powder coatings. I called up a fellow there and told him about the idea, and he was extremely kind and prepared up some samples of black powder coatings, one a polyester, and the other a polyester-epoxy hybrid. jason and i did some tinkering with both these as well as some laser printer toner (since it's carbon mixed with a polymer). jason tried both with the hackerspace's laser cutter, as well as just heating a bunch of the stuff up in a popcan. in both cases each powder (polyester-based, polyester-epoxy hybrid, as well as laser toner) fused, but the product was VERY brittle. the pop-can tests that melted material to be a few millimeters thick showed that the problem seems to be with the material itself -- unfornately, even relatively thick pieces would snap pretty easily. (though powder coatings do contain quite a few different materials in them for curing, flow, and pigment, so it's quite possible that some particular combination might work). so, not much luck on that front. i would really like to get my hands on a good couple of cups of black ABS powder, or make some. (random thought: i think the size of the powder will be fairly critical -- ideally one would want to maximize the ratio of surface area to volume of each little ABS grain, such that the laser diode could more easily heat up relatively little volume). --- so, i decided to work some on a little test rig to try out different powder materials (and, conceivably, with some better seals, you might even be able to use it for liquid stereolithography). i figure that you don't need a great deal of print volume to test if the material is viable or not, so i decided to make a "mini stereolithography" system -- infact, it's almost pocket sized, save some of the larger mounting bits. here's my progress so far (in picture form): (click on the thumbnails for much larger versions)
first i went out and picked up this DVD burner. it's a 24x (the fastest i could find), so the diode in it should be around the 200-250mw range if memory serves. (clearly here i should add in the usual warnings -- LASERS CAN BLIND YOU AND THE FOLKS AROUND YOU INSTANTLY, unless you know exactly what you're doing and take appropriate saftey precautions, you shouldn't attempt this!).
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i had wandered around home depot for half an hour or so for ideas to make the indexing build chamber for the powder. i figured that a simple idea would be to just make it round, and find two pieces of pipe that fit snugly within each other -- the outer one would be the chamber, and the inner one would have a little piece put over the top to act as a "table", and index down within the larger outer pipe by a small lead screw or some other mechanism. here are the various pieces of pipe that i found. i think the outer pipe (the black one) is around 1.25 inches in diameter.
they fit together something like this, where the "table" ends up mostly inside the "chamber", starting mostly near the top but being able to be pulled down quite a bit. the "lead screw" piece is always outside of the chamber, and doesn't move up or down. (the "table" would index up or down, while the "chamber" and "lead screw" parts would be vertically stationary).
and removed it, revealing a nice perfectly sized hole!
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so, that's my progress so far, and now i'll have to forage for some tiny steppers to both index the table, as well as move the laser on the x and y axis. the travel is extremely small -- the build area will be about an inch in diameter, with a height of about 1cm. that's pretty tiny, but should be more than enough to test different powder materials to see if they can successfully build very small parts with sufficient structural integrity. the neat thing is that the whole thing can come apart pretty easily, so it can be washed out to prepare for a new material. hopefully once the steppers and axis are on there, it'll still be just as easy. hope you've enjoyed my little story! (and i hope my supervisors don't read it -- i'm supposed to be working on my dissertation). ~peter TextThis is a generic Widgit Banger! I (Mr. Bunny) made it because it's cool but I use it to make Widgits. Share and Enjoy! (This page was made using the wiki page Development:Example as a model.) Entrepreneurship (Kits)Mr. Bunny may have a cottage industry making and selling kits. He's also the developer. If you want to buy a kit, he's the best person to buy one from. And he's got a link to his paypal account on his homepage. (Listed in the user box above.) Files and PartsGeneric/Daughter_part and CarrotStraightener. (As a gentle style recommendation, it's good to try to keep all your parts and files on the RepRap wiki rather than scattered around so that Mr. Bunny doesn't have to use a scripts and so on to get stuff back onto the wiki.) File:Uploaded files example.zip Photo 1Flicker Example<flickr>2967868906|right</flickr> Working NotesProject Lead(s): Mr. Bunny Wiki-maintainers and helpers: Forum thread?ToolingDescription of tooling requirements. ProcessWhat is making the part like? NotesIntial announcement: http://builders.reprap.org/2010/02/first-tests-building-powder-based.html Related |