week 17 Header Img

Week 17: Propose the final project



This week neil gave us a bunch of questions about our final project to answer...
So let´s think about my paste-extruder

What will it do?


As the name says, the paste-extruder will extrude pastes ;)
Mainly it is planed for chocolate, but also marzipan, concrete or ceramics should work with it.
The extruder will be splitted into two parts: a reservoir and the extruder. Both parts will be heated for making the chocolate pasteous. They will be connected by a short piece of silicon-hose.
All parts will be made out of food-safe materials and easy to clean.
The extruder-control will be stand-alone, so it is universal to any kind of XYZ-Machine. The only signal used will be the step-signal for the forward feed.

Reservoir and extruder will be thermical-isolated by a mixture of gypsum and styropor.
This prevents burned fingers and will safe a lot of energy.

Who's done what beforehand?


You can find a lot of paste-extruder-projects on the web.
At reprap.org is for example a long list of these projects.
Most of them uses a syringe that is compressed by some kind of mechanic. I think that this is very inaccurate, due to the compression in the material. The material-flow is not very even, and the flow doesn´t stop immediately when the extruder-motor stops.
Because of this my extruder will use a syringe only as a reservoir, but for the extrusion itself a archimedes-screw.
I found only one project that goes into the same direction: 0x7d.com
Main differences to this project:

  • My syringe will not be driven by air pressure, but by some kind of e-motor (lack of compressed air ;))
  • My syringe will be heated
  • My archimedes-screw and the needle will be heated
  • All parts will be made out of food-safe material


    • What materials and components will be required?


  • The syringe for the reservoir will be a "Perfusor"-Syringe from bBraun: bbraun.de
  • The syringe will be compressed by a dc-motor with some kind of trapeziodal-screw
  • The extruder will be driven by a stepper-motor
  • All other parts will be milled out of aluminium
  • The electronic will regulate the temperature, the feed of the syringe and the feed of the extruder


    • Where will they come from?


  • Syringe: pharmacy
  • DC- and Stepper-Motor: amazon or ebay
  • Aluminium: DIY-Store
  • Heating: Kanthal-wire and Kapton-Tape
  • Trapeziodal-screw: left over from the Poor-Mans-Mill (MTM)
  • Archimedes-Screw: milled by hand out of aluminium
  • Electronics: selfmade, components from farnell, mouser, etc.


    • How much will it cost?


    Hard to say, but i think about 100$ all in...
    I will write a complete list in the documentation of my final project, but till then i will update this list:
  • Kanthal-Wire: 10$
  • Kapton-Tape: 10$
  • Stepper: 7$
  • DC-Motor: 10$
  • Aluminium: 30$
  • Syringe: 2$
  • Silicon-Hose: 2$
  • Trapeziodal-Screw: Left over from the MTM-Week: 0$
  • Electronics (Controler): Fab-Pic from the Hello-World-Assignment or a new one (sample): 0$


    • What parts and systems will be made?


  • The holder and heating for the syringe
  • The extruder and heating for the extruder
  • archimedes-screw (hopefully)


    • What processes will be used?


  • 3D-Print and Lasercut for the first test-parts
  • Lathe for the most parts
  • LPKF-Mill for the electronics
  • Gypsum-casting for the isolation


    • What tasks need to be completed?


  • Drawing sketches on CAD
  • Design the feed for the reservoir
  • Mill the hardware
  • Design the electronics
  • Implement the PID for the temperature-controler


    • What questions need to be answered?


    My main problem will be the milling of the archimedes-screw. I´ve got no clue how to build this part...

    What is the schedule?


    Due to my visit at the Fab12 my deadline is the 9.7....
  • 1.6. - 11.7.: Make the drawings and buy material
  • 11.7. - 25.7.: Building the parts
  • 25.7. - 2.7.: Program the electronics
  • 2.7. - 9.7.: Evaluate and making improvements
  • 9.7.: Deadline!


    • How will it be evaluated?


    Well, this task is easy and not Weight-Watchers-Compatible. I think i will print a lot of chocolate :) Yummi...

    Now you should have an idea about my final-project. Stay tuned for news...
    So long, have fun!