Friday, July 21, 2006
I'm toying with the idea of using a syringe approach in the repstrapped extruder. I'm a bit concerned about air bubbles, but will have to try it.
It would fit the machine something like this.
I'm using a Tamiya planetary gearbox that appears to be readily available all around the world. The planetary gearbox is great because it spreads the load across more than one gear to reduce stresses and it's all in-line. So that means the motor can move up and down as it drives the syringe without getting too much in the way of other things.
The motor drives a threaded rod that goes through a nut, which causes the whole motor assembly to drive up or down. Guides prevent the motor body from turning so it can only go up or down.
Here's a diagram of the whole as well as a cut-away picture and a picture without the PVC pipe and thermal mass. Click the images for a close-up.
It doesn't hold a huge volume, but this is just an experiment. The three nuts connecting the top half to the bottom half can be removed to re-fill the heater tube.