NTC thermistor bridge

(Backdate: Dec. 1, 2016)

Today I built the thermistor-based temperature measurement bridge we’ll use for extruder barrel thermal control system. I specced a kind of glass-bead thermistor last week, one of the very few on Digikey that can get up above 250 degrees…

Digital caliper data collection

(Backdated: Nov. 10, 2016)

In order to measure the diameter of our filament, we decided to use digital calipers with a data output port.

Using Asana for Sprint Cycles: A Retrospective Journey

Our team utilized a sprint cycle methodology for completing tasks throughout the project. For those unfamiliar with the sprint cycle, it’s a theory of project management that goes a little bit like this:

Heater coil construction

(Backdated: Nov 10, 2016)

Today I built the heating system for our extruder. I made a new heater coil out of about 1 foot of Nichrome wire and crimped it to the end of a length of 18AWG speaker wire (in order to handle the high current required). I hooked it…

Python packages!

When I started building the ReFilament GUI, I started with the Python package Tkinter. I had already heard of Tkinter and from what I could tell, it was relatively easy to use. Building the homepage only took about 10 minutes, so it seemed like a viable option. Then I started to play with…

Switch to Thermistors

(Backdated: Nov 29, 2016)

Today I finally bailed on thermocouples. I couldn’t for the life of me figure out a good way to measure the tiny voltage they produce, even with an instrumentation amp with buffered inputs and a high gain stage. In light of that, I…

Choosing a heater

(Backdated: Oct 24, 2016)

I started this sprint out strong with some research into heaters. Basically, we saw two different options for heating up the barrel of our extruder: ceramic heating elements or a coil of nichrome wire.

Bubble Adjustments

(Backdated: Oct. 28, 2016)

Our first Sprint Review was today, and we got some great feedback from our reviewers. For instance, we were advised that air bubbles can be eliminated using vibration or vacuuming. Both of those will be difficult to implement, but either one…

Heater coil experimentation

(Backdated: Nov. 8, 2016)

For some experimental validation, I made a preliminary heater coil out of 1 foot of nichrome wire and heated it up with a lab power supply. In order to handle the higher current that this application would require, I assembled…