Week 2: Configuring the right slicer software/ changing Ultimaker firmware

Just before the end of last week’s very productive week we found a piece of sofware that would greatly reduce our developing time to create a GCODE (data file sent to 3D printer), which would incorporate the usage of a second extruder nozzle. In our case, we will use a mixing nozzle that will cast a silicone mixture in the PVA (polyvinyl alcohol), as described in Methods. However, this is not as easy as it seems, as the datafile contains only a path to be followed by the printer head, and now needs to activate the right steppenmotors of the different extruders at different times.

Using Repetier host, we managed to edit the slicer settings of both the CuraEngine and the Slic3r to incorporate a second extruder in the settings. Now only the motherboard of the Ultimaker 2+ needs to recognise this extra hardware which is done by editing the firmware. This is what we are working on at time of writing, and will be updated as soon as we have made progress

Recap: Week 1

This week our focus was to get up to speed quickly. After learning what our project goals are, we immediately delved into the literature provided by our experts Rob Scharff and Lars Rossing. From this literature we quickly learned the basic principles of Soft Robotics and UltiCasting and were able to apply these on the Ultimakers.


Our first print was a test piece used to determine the accuracy of printing with flexible materials. After this we started printing basic soft actuators with the aim of making them airtight. After some trial and error this proved to be quite challenging due to the still a bit unpredictable behavior of the flexible filaments. Our progress and used settings can be found in the FDM Test Results tab.


For the UltiCast project we are programming a script that can use the provided G-Code to estimate the needed filling volume and deposit location for the casting automatically. This software will be used to drive the casting process. We are also setting up the hardware for the UltiCast process but we still have to receive the actual silicon filaments to start testing. We hope to really kick off the UltiCast project next week.

Stay flexy, stay sexy!


Printed Cast without textUltiCasting, researched by Lars Rossing, is a new add on for 3D printers to speed up the printing time needed for filled structures. The basic principle involves first printing a mold and then filling this mold with a settling resin. In the video you can see the process of UltiCasting.

In the field of Soft Robotics these techniques could prove interesting. With UltiCasting it becomes possible to ‘print’ a soft actuator in a mold eliminating the manual casting process and doing so speeding up the process of creating soft actuators.

We will be using a water soluble PVA to create the casting mold which will be filled with a two component silicon fill. This will allow more complex shapes that could not be printed without support to be created on a direct drive 3D printer. If the mold quality is high the surface quality of the flexible silicon will also be very high. This is very hard to achieve in traditional FDM printing because every layer of hot filament deforms the previous layers of filament.

We will be researching the possibilities and limits of this technique and it’s applicability to the field of Soft Robotics