Week 2: No longer cast away with UltiCasting

Yesterday we have made major progress on the UltiCast project. After experiencing some setbacks with the Ultimakers we finally managed to get a second cold extruder running on the Ultimaker mainboard. Before this success our most noteworthy accomplishment was that we not only crashed the Ultimaker during testing, it also froze on startup and for some reason was completely inverted. Luckily with the help of our supervisor Lars Rossing and some tedious hours fiddling through the Ultimaker firmware in Marlin we now have a very promising set up. Our current setup will be available in the methods page.

To celebrate these successes: Here is a video of our latests FDM printed finger!


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!

FDM printing with Ninja Flex

Ninja Flex is a highly flexible polyurethane based filament ideal for direct-drive extruders such as Ultimakers. Using this material could simplify the production of soft actuators significantly and speed up the process.

We will be investigating the properties of this material, the optimal method of printing it and the possible applications in the field of Soft Robotics. Especially for Soft Robotics it is desirable to create an airtight actuator to gain maximal control of the movements, when pressure is applied. To do so we will experiment with a lot of different printer settings and log our results in this blog.


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

Getting a grip with printed Soft Robotics

Hi and welcome to our weblog!

In the field of Soft Robotics 3D printing is rapidly becoming a more and more interesting tool to create soft actuators. The possibility of 3D printing silicons might prove revolutionary in the field of Soft Robotics.

We will be investigating two new methods of using 3D printing to make soft actuators. First we will investigate to possibilities of directly FDM printing flexible materials using an Ultimaker. Secondly we will look at the possible advantages of using a new technique called UltiCasting. More on these techniques will soon be posted in our weblog.

During the upcoming weeks we will post our research progress and prototypes on this weblog so be sure to follow us if you are interested in our progress and comment if you have questions or feedback!

Max, Luc, Olivier and Christoffer