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Fig. 1 This is a build log about making a 3D printer, but before diving into the construction here is a bit of background about what these things are and what they can do. Figure 1 shows a representation of a Mendel type printer. If you recognize it and already know about them, you can skip to the next section. The kind of machines I am referring to are the plastic filament type 3D printers that are like a CNC mill, much smaller than a CNC router table, but with a kind of hot glue gun pointing down where the router would be. The glue nozzle is moved around, extruding the melted material, building up the part, layer by layer. It doesn't actually use a glue gun, but a more specialized device that allows its temperature to be feedback controlled by the computer with a mechanism to force a plastic filament line into the heated nozzle, also under the computer's control. So - the computer accurately controls the nozzle position in three dimensions, as well as the flow of the material on to a surface - that's the basic idea. In general, this kind of process is called additive machining, because you add material to make the part, while CNC mill operations are referred to as subtractive machining, since you remove material to make the part. This melted plastic filament machining is also referred to as Fused Deposition Modeling (FDM) or sometimes Fused Filament Fabrication (FFF), but it is more commonly just called 3D printing. That's a bit of a misnomer, though, because there are several other types of 3D printers, like laser sintering or stereolithography for instance, but that is for further reading. One of the other primary differences between a mill and these printers is that a mill needs to be quite rigid and massive to be accurate, which means subtantial power is need to increase speed. A 3D printer needs to rigid and accurate as well, but the forces involved are greatly reduced. Also, required time to print the part goes up quickly with size, so speed is quite important and therefore, moving parts of the printer needs to be as lightweight as possible. The filament material most often used is either PLA (polylactic acid), or ABS (acrylonitrile butadiene styrene) although I have heard of folks trying nylon, weed wacker line, wax, wood (a sawdust-resin filament), chocolate, sugar, or even pewter on these type of machines. There is also a type of ABS that changes color with temperature, which can make some interesting objects. PLA and ABS comes in 1 kilo (2.2 pound) reels of filament and right now they cost roughly the same, about $20-$30 or so for a reel. The filament is usually either 3mm or 1.75mm in diameter, and their dimensions and purity are important. They make motorcycle helmets out of ABS, but more about these plastics later. There are many types of 3D printers out there now - some you buy ready to use, others are kits, and some that are just open source designs that you can read about, order the materials, and go from there. The amount of information to sift through is large. One effort to catalog these designs is on this page, but this stuff is moving very rapidly, and it is hard to know when or where to dive in. I decided it was time for me, and this webpage is a build log of making one of these that best fits my situation. This whole idea took off with the idea of making these machines from parts made by other 3D printers - a "replicating rapid prototyper," from which the name reprap derives. Adrian Bowyer of the University of Bath, UK, deserves a lot of the credit for getting this started in 2005. Since then, Reprap has grown as a community of users and a repository for open source hardware and software designs on these things. Also, there is a large repository of designs for things you can make with these, called Thingiverse, which was started by Makerbot, a 3D printer manufacturer, and its fun to browse the designs there or at GrabCAD. That's the dream - browse through the catalog, download a design that you want to make, and send it to your machine to make it. Not quite "Tea, Earl Grey, hot" but we're getting there! So, the work flow for making a part starts with a digital 3D model or design, which typically takes the form of an .stl file, whose extension is derived from STereo Lithography. You can either download the .stl file from Thingiverse, or make your own part with a commercial 3D drawing program, like AutoCAD, Solidworks, Edgeworks, etc. or use a free open source version, like OpenSCAD, FreeCAD, Sketchup, etc. Even if you are designing something new, you might find it easier to start with one or more designs that are close and then modify or join them together rather than start from scratch. However, most CAD programs will not import an .stl file, so there must be another format of the design availalble in order to modify it, and then after modification it is saved as an .stl file. In any case, the result should be a 3d model in the exact measurements of what you want in the form of an .stl file. The second step is to convert the .stl file to g-code, the same code (with a few machine specific additions) used on CNC milling machines. This is usually done with one of several freeware CAM program like Slic3r or Repetier (Repetier has Slic3r built-in) or KISS slicer, or Cura that slices the object, layer by layer and generates the g-code needed to position the extruder nozzle to lay the plastic layer over the part, and then moves the nozzle up to do the next layer, and so on. (I believe "Repetier" is usually pronounced to rhyme with "rocketeer", although I have heard some on YouTube pronounce it in French fashion, like "re-PET-tee-ay" but I don't know why as I beileve the author is German.) Once you have the g-code file, the third step is to print the part by starting the controller, or "host" software to read the g-code, line by line, and send the proper pulses to the stepper motors on the printer to position the nozzle, as well as control the temperature and feeder of the extruder. Each of these three steps may be done on the same or separate computers. However, the third step is timing sensitive and compute intensive, so typically that computer can not be doing anything else while printing, and some models take several hours to print. Well, that is a very brief introduction to the idea of 3D printing. If you click on some of the above links, you will find there is a lot more to it, but if you are new to it all, this description should help some of the pieces fall into place. To continue with the build log for the particular printer I built, called the Gilbert - click here. (A note about using this website - if you want to see any of the photos on this website in a larger format, you can. If you are using Firefox or Internet Explorer, right-click on the photo and select "view image..." If you are using Chrome, right-click on it and "open image in new tab...") Comments may be addressed to gary at liming daught org. Visitor Map
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