RepRap Printing Overview

By James on Wed, 25/05/2016 - 09:52


The spools of plastic to print with cost £10 - £20 / kg and they come in an array of colours.  The most common are PLA and ABS, although nylon and others are being used:

  • PLA is most popular as it is a biodegradable plant based plastic, non-toxic (apart from some coloring) but is not suitable for higher temperature (e.g. printed cups/plates will deform in the dishwasher)
  • ABS is petroleum based, has a toxic smell during printing but will withstand higher temperatures.


There are 3 main steps to printing an abject:

1. Obtain a 3D model (Usually in the form an STL file)
   Two options here:
       a) Download - Thousands of open source designs available for download from sites like:

       b) Own Design - Using CAD software and a lot of patience/practice almost anything can be modeled in 3D and exported to a STL file.  Lots of open source modeling software available.. I'm getting experienced in and would recommend OpenSCAD for a fellow programmer, or FreeCAD for a normal computer user. I can demonstrate either/both of these.

2. Slice

Slicing takes the 3D model (STL file), and converts it into gcode (the instructions that the printer follows to print each layer). Here we choose various settings specific to the print (like layer height and width, number of external perimeters, number of solid top and bottom layers, infill density and pattern being the most basic) that will affect the strength, quality and speed of the print. I use and can demonstrate Slic3r, but again there are also many other slicing software available.

3. Print

Once the model (STL) has been sliced into gcode, the gcode file is put onto an SD card, plugged into the printer and printing begins. The first layer is critical as it's the foundation for the rest of the print, its worth paying close attention and aborting and starting again at this stage if it doesn't come out near perfect. Once the first layer is down its usually then just a watching and waiting game...