Printing a Printer
The word “RepRap” comes from the term “replicating rapid prototyper” and one of the original ideas and ultimate goal is for a 3D printer to be able to replicate itself. And while we aren’t quite there yet, there are some designs that come surprisingly close. The G&C CoreXY has a lot of printable parts, and to save costs I am using my i3 FrankenPrusa to do the printing, with the occasional assist from the printers at MidSouth Makers, the local makerspace that services the Memphis/Mid-South area:
The Printing Primer
There are many different types of 3D printers around, from industrial types used by government or corporate research and development departments that can run hundreds of thousands of dollars down to the “consumer” level that may now only run a couple of hundred dollars. For this blog I will be discussing the consumer level printers, specifically the “Fused Deposition Modelling” (FDM) type.
When creating 3D objects via computer there are generally two ways to do it – via a subtractive process where the Computer Numeric Control (CNC) controls an item with a blade or cutting bit like a router or spindle and the material is cut away and the 3D item is left behind. The other method is via an additive process where material is built up layer by layer to form the object. There are pros and cons to both but for the home user the additive process generally wastes less material, is overall safer and is less expensive to get into.
Most inexpensive 3D printers are of the FDM type. The best way I heard it described is a “computer-controlled hot glue gun” and that is a fairly apt description. Essentially an FDM 3D printer takes a plastic filament, feeds it into a heated chamber where it is melted and forced out through a smaller nozzle to create a strand. That strand, still in a melted state, is deposited onto the build surface via directions given to it by a small microcontroller that tells it where to move the print head. Layer by layer more plastic is laid down until an object is formed. If you look at the picture below, the red, green, yellow and pink pieces are all 3D printed by the FDM process. If you look closely you can see the striations as each layer is printed, and if you look at the pink pieces on the buildplate and in the video above, you can see the hatchwork of the interior portion of the print, or the “infill”:
The heated chamber is referred to as the “hot end” and the device that drives the filament into the hotend and eventually out the nozzle is known as the “extruder”.
In my next build log post, I actually start to put stuff together and discuss cartesian vs polar, some of the different styles of FDM printing and why I chose CoreXY vs other designs.