Open Source Hardware
From Fibres to Fabrics
This week we looked into different ways of how to ‘hack’ existing hardware/machines for the textile industry.
Batik waxing using a Kuka robotic arm
Using the Kuka at the Fab Lab Barcelona we attached a small container with nozzle and heating to the tip of the arm. While the tank would be filled with melted liquid wax, heated with an external generator. The arm would move it according to a digital design prepared in Rhino and move along the desired path and wax slowly be dispensed through the nozzle to create a wax print.
The concept of this experiment was to use the robotic arm as if it was a large scale 3D printer applying wax on fabric suspended on wooden frames. These printed on fabrics could then be used to naturally dye them. All areas covered by the wax design will reject the colour solution and remain their natural colour.
Set-up of the extruder designed by Mohamad Elatab
Materials needed:
- 12V power supply & wired nozzle heater (to heat nozzle and keep wax liquid)
- Aluminum funnel
- Aluminum frame
- Wooden teethed ruler height 4mm (able to laser cut it)
- 0,6mm Nozzle
- Bolt & pneumatic cylinder with round rod (to close nozzle when needed)
- Kapton tape
- Nichrome wire
Apart from the wooden ruler all parts of the extruder were made from waste materials at the lab. The ruler was custom-laser cut to fit the height of the aluminium frame and funnel.
Assembly steps
Screw the nozzle onto a funnel with an opening dimension matching the nozzle. Once the nozzle is securely attached, cover the outer shell of the funnel in Kapton tape. The tape will insulate the heated funnel and prevent the wire that will be added in the next step.
Attach the ruler to the funnel to have it reach along the entire length of it. In this example the ruler was cut in two parts to better adapt to the angled lower part of the funnel. Wrap nichrome wire around the funnel with the ruler in a spiral way going from the nozzle to the top opening of it. Then attach another layer of Kapton tape ontop of it.
Combine the bolt with the pneumatic cylinder. This part of the extruder will control the flow of wax. To close the nozzle the bolt will by extended to its opening via air pressure to block the opening and stop wax from leaking.
Now the funnel can be attched to the frame that will connect it with the Kuka. In this step also the nozzle heater is placed which will later be connected with the power supply.
Place cylinder and bolt into the funnel and fix them onto the frame.
As the last step connect the frame to the Kuka, so it can move all parts and make sure the nozzle heater is connected to the power station.
The design
To make sure it drips as little as possible (the bolt will close the nozzle but since it had never been tested before we wanted to be safe), we decided to create single path designs. That way the Kuka could continuously move along the canvas and extrude wax until the design as fully been applied to the fabric.
I used StippleGen2, imported a photo I took in Vienna this summer. Putting the stipples up to 6000, I exported the TSP path as a SVG-file.
As SVGs cannot directly be imported into Rhino, I used Inkscape to export it into a DXF file.
In Rhino I added my curve to a provided grasshopper definition that will ensure a clear path for the Kuka to follow.
Building the frame stretching the fabric
Printing with wax
Calibrating the position of the frame, design and height of the nozzle, we realised that the vertrical supports we had added to stabilise the frames, influenced the height of the nozzle and made it stuck. We removed them to create a more even plain bed for the extrusion.
After filling hot wax into the funnel, the extrusion process could begin.
The wax lines were quite fine, by increasing the speed of the robot movement, the width of the lines decreased. While my design was printing, the nozzle got clogged by hardened wax parts. We had to stop the process and reopen it with a needle in order to continue. The stopping and restarting of the file influenced the width of the drawn lines and well as resulted in some splashes do to the air pressure closing the nozzle.
Kuka knitting idea
I am currently researching how a Kuka could directly be used for textile production. Base of my investigation is the question: What textile related process can be done by using only one hand? A pulling, pushing or paint-like movement?
- Knit with intersection supports
2. Pulling fibres into final garment shape
