This document provides information on the machines used in the workshop on open‐ source 3D‐printers and milling machines, at the Howest Summerschool on the 31st of August. If you prepare a small 3D‐object and/or a 2D‐profile to be cut, you will have the opportunity to print/mill this yourself during the workshop. This document outlines the parameters of the files to be prepared. It also provides links to the software you’ll need. Installing this ahead of time will allow us to get started faster during the workshop. Please do so. If parts of this explanation are unclear, or you’ve got stuck while installing the software, you can contact: firstname.lastname@example.org PART1: MAKERBOT 3D-PRINTER Machine: The makerbot is an open‐source design for a 3D‐printer. This means the build plans are distributed on‐line and all users can modify or (try to) improve their machines. Over 5000 of these machines have been built and because of this open‐source design strategy they are evolving very fast. The machine creates small objects in plastic (ABS or PLA). This is done by melting the plastic in a hot print head, then extruding a thin filament of this plastic. The machine then draws with the plastic and builds the 3D‐object layer by layer. http://www.makerbot.com
Examples of objects made on the Makerbot Process:1‐An STL‐file is imported into the control software, REPLICATORG. .STL is a 3D‐file format. Most 3D‐software is capable of exporting in this format. Objects need to be ‘watertight’: they need to have an inside and outside.
3D‐model in replicatorG 2‐ When this is done, the 3D‐object is cut into layers. Each layer is a 2D drawing. This is converted into a description that can be sent to the 3D‐printer. This is complicated to achieve, but there’s a preconfigured piece of software to do this for you. It is called SKEINFORGE, and is integrated into ReplicatorG. Skeinforge has a lot of customizable settings, allowing you to define things like layer thickness, solidity of your object, print speed and temperature. As a novice user you can use preconfigured setting, but sooner or later you will need to dig into this. GCODE of the object in the previous image 3‐The output of Skeinforge is a text‐file with machine code. This code is called GCODE, en is in essence a long list of X,Y, Z‐coordinates to be sent to the printer.
4‐In ReplicatorG there is a CONTROL PANEL. This controls the printer directly. You use it to position the print head and to heat up the printer. 5‐Once this is done, you send the Gcode to the printer, and build the object Limitations: ‐like most 3D‐printers, this technology is limited to small volumes. Big objects take long to print. ‐these machines do not print a support material, unlike most commercial machines. This means you can’t lay down plastic in mid‐air. The little whistle in the image above is printed on its side, you can’t print it the right way up. Overhangs of more than 45° are not possible. File description: Format: STL‐file* Maximum dimensions: 5x5x5cm** Maximum overhang: 45° Minimum wall thickness for hollow objects:1mm *Autocad, 3Dsmax, Sketchup and most other 3D‐software can export this. **de Makerbots can print up to 10x10x12h, but within the context of this workshop this would take too long. Alternatively, your object could consist of multiple smaller objects, spread out over a 10x10 build surface. Preparation: 1‐Download en unzip Replicatorg: http://www.replicat.org 2‐EITHER: prepare your own 3D‐model to be printed, within the constraints described in ‘File Description’ above. OR: Go online and take a look on http://www.thingiverse.com You can find a lot of objects there that can be printed. Choose something that is not too large and that has actually been printed by more than one person. Save the file and bring it to the workshop.
PART2: timelab’s MINICNC Machine:Timelab’s miniCNC is a small milling machine with an open floor. It was designed to mill small details into large panel or wall surfaces. The machine has been developed into an open‐source kit and uses the same electronics as the Makerbots. http://www.repairablemachines.com Example of drawing, milled out of 5mm multiplex
Process: The software does not use a 3D‐model, though the machine can do 3D‐objects. For ease of use, the software uses a black & white or grayscale bitmap. In a Python‐script the Gcode for the machine is generated from this 2D‐drawing. The orange lines in the image above are the generated tool paths. These are saved as Gcode and then opened in ReplicatorG. ReplicatorG controls the machine in the same way as it does the Makerbots. Limitations: ‐de Dremel can only be moved straight down. You can mill the top half of a sphere, but not the bottom half. (though we will focus on 2D for this workshop) ‐the machine can move the Dremel 5cm up‐and‐down. In practice you will be limited by the length of your milling bit. You can find a 3mm‐wide milling bit that is 5cm long, but there is no such thing as a 1mm milling bit of 5cm length. ‐when milling a square hole into a surface, the inner corners will bee rounded off by the radius of the milling bit used. ‐the machine does not have a cooling system on the milling bit. You can try milling aluminium, but you will have to take care not to overheat the milling bit.
File Description: Format: PNG‐file, 200 dpi, black&white* Maximum dimensions: 18x18cm Minimum detail: 1mm ** *Everything in black will be milled away. The black areas of the design should not touch the borders of the image. **This is the diameter of the smallest milling bit available Preparation: 1‐Install the software: an overview of the software to be installed can be found on http://www.repairablemachines.com/downloads.html a‐You will need ReplicatorG. This should be installed already if you prepared for the Makerbot. b‐You need a driver for the machine. This is an XML‐file that needs to be copied into the ReplicatorG install‐directory. See website for details. c‐ You need to be able to run Python. This is a programming language you can download and install. This is the tricky bit, as you also need to install a number of libraries. The instructions can be found on the webpage, but differ from platform to platform. If you are unsuccessful installing these, mail email@example.com for assistance. d‐ You can test if everything got installed correctly by trying to run the Python‐script at the bottom of the download‐page. It should run and look similar tot the image above of the software (the image with the ‘A’ under ‘Process’) 2‐OPTIONAL: Prepare a PNG‐file, within the parameters described above, of a design you wish to cut out of plate material. Materials like wood, plywood and plexi will be available at Protospace. Best of luck & see you all on the 31st, Lieven