The rise and fall of an Extruder and its replacement…
So after doing some experiments with the laser and the Reprap mendel I posted the video to YouTube to share with some friends that are into 3D Printing and such. Eventually Casainho found the video and asked for some explanations of what was happening. I promptly explained to him my setup and he told me about his project of etching PCBs with a laser and Reprap. So I agreed to make some experiments for him since he didn’t have access to the equipment necessary to replicate my setup.
One of the goals was to get 0.25mm tracks for some solder mounted chips so I tried several laser focus distances until I got one that looked really precise and made this:
It wasn’t perfect but it was a good start.
I tried a lasing some permanent pen ink on a PCB but didn’t get any results.
After that I tried paper again this time I changed the speed os the laser passes and got really nice results:
After theses tests I got the parts for my extruder and halted immediately the laser tests to build it.
I had to drill 2 extra holes on it so I could fit the PEEK block on it since it was smaller.
Yet one thing was missing the aluminium block, the power resistor that would heat the hot end and the thermistor. I was so nervous and wanted to print so badly that I used some nicrome wire that I had and a rather large 100k thermistor that I had around and started the machine to maque some prints. The first thing to do was to choose what to print. But that one was easy, it would be some gears since mine where slipping and where hot glued to gain some friction to the motor. After that I just had to wait for the thing to heat up and start printing.
That was when something strange started to happen and the demise that was upon me started to reveal it self. First I was using PLA and was sure that the temperature reading was between 180ºC and 200ºC (don’t EVER trust big thermistor readings) but the plastic came out full of bubbles and it was making smoke rings (yea WTF…) some one on the IRC channel told me I had my Temperature to high, but for me that was preposterous my readings at the time where at 170ºC. I checked if it was jammed or something like that but it didn’t seem so.
At that time the harm was done and I only found out the full extent of the damages after I disassembled the extruder and inspected the hot end. The PEEK partially melted. the plastic was flowing between the PTFE and the metal and they where really tight everything when bananas… I tried to fix it somehow with PTFE tape but it didn’t work, even after I gor the block the resistor and the thermistor it didn’t work. It starteed extruding correctly for 3 seconds then stopped, I pulled the filament out tried again and it was the same thing over an hour… My first big Reprap failure…
So after my demised I rendered myself to laser engraving…
At least until my replacements arrive.