33. 3D Printer-addon

This is an attachment to my current CNC router that allows 3d printing as well as milling. The pictures are a bit sparse, but the project will be revisited when my next router is complete.
The actual build is rather simple. The heart is a direct driven extruder with a rather beefy stepper motor that I bought from China. It came with a k-type thermocouple, but without any electronics. What I did was build an instrument amplifier with the classic LM358 and read the temp value with an arduino pro mini. The arduino also runs a PID algorithm for controlling the power mosfet that switches the heating element. I first used a small heatsink like the black one you can see on the LM317 in the pictures, but that one ran really hot. I then switched to an old processor heatsink, and all I can tell you is wow. It went from frying my fingers in a second from turning it on to being completely cool for hours on end, I never imagined it could be that much of a difference.

The arduino is connected by serial interface to my computer so that I can monitor the PID values and the actual temperature, assuming the k-type to be roughly linear and having 41uV per degree. This isn’t 100% accurate, and I will be switching to a thermistor when I get back to this project. The extruder is set up as axis A in mach3, and then the classic 3d-printer software toolchain that I guess everyone is familiar with nowadays is used to convert solidworks models to gcode. Should be worth mentioning that I’ve only done two prints so far, the skullopus being the first test and a companion cube for my girlfriend to take with her while we stay apart during the summer being the second. She liked it very much until she “accidentially” vacuumed it.

I do have a few videos of it running, but I think I’ll make new ones later on and upload those instead. Oh yeah, I’ve got the arduino sketch here if someone’s interested. It’s a bit of a work in progress as well.


One Response to 33. 3D Printer-addon
  1. Tumblebee says:

    I did retrieve the companion cube from the vacuum cleaner after I very accidentally vacuumed it.
    /The girlfriend

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