My Adrian's Geared Extruder got jammed (again) so I took apart that old extruder to replace it.
|White ABS quite stained from heat and fumes. I've seen this before somewhere.|
So, with a bracket that I customised for shorter bolts from another design someone sent me, I hobbed an M8 bolt and constructed a Hinged Accessible Wade's Extruder to GregFrost's design.
|My first attempt, not too bad (moved along slightly at one point when I found a slim washer that would allow me to cut at a better distance along the bolt), though I did another one later that was better.|
|The oversized cork later got squashed very slightly as it took up the compression from the hot-end fixing bolts.|
For a temporary X-axis I used Prusa's standard one for PLA bushings, since I had a spare one sitting in a box that looked ugly due to previous problems with backlash.
|So far so good...|
Annoyingly, the extruder started to jam when I was trying to print with PLA, and a few other things that I tried to print did similarly.
|An earlier design for the clip that didn't work well due to the axis it was printed in (the bottom print surface is on top in the picture, and the bolt clip snapped off by delamination/peel stress).|
|Bases of a pulley that I wanted for my x-axis idler, and the filament guide, on the left and right respectively.|
I soaked the nozzle in acetone for about 3 days while very busy with other things and when I got round to taking it out, I found that there was still a significant amount of undissolved plastic stuck in there, which was mostly easy to remove with hand-applied torque on successive sizes of drill bit.
The nozzle outlet, which is 0.5mm in diameter, was a pain to clear out as I couldn't find a pin or needle that thin anywhere, let alone a drill bit, so I eventually used a short length of copper wire from a bag of scrap wire insulation that I'm hoping to find a sensible way to dispose of.
Very frustratingly though, upon trying to put the hot-end back together, I found that the threaded end of the PTFE insulation no longer fit the thread inside the brass nozzle, and was starting to strip the tread when I tried to put it in.
|PTFE? Warping? Oh right, yes that does happen sometimes. -_-|
While trying to run a print again, I wasn't happy with how much friction the PLA bushings add to the sliding of the x-carriage, and how loosely they held onto the smooth rods, so I decided to design a new x-carriage with the combination of properties that I need.
When I came round to trying to print parts for my new x-carriage in ABS, I was faced with a couple more extruder failures, so I tried successively reducing the distance that filament retracted during moves from about 1.2mm down to 0.8 then 0.5 without it helping much, also increasing the target printing temperature from 240 to 245C. Sadly, this didn't help, and I was unconvinced that the clogged nozzle was my main problem, as on trying to manually push filament through the hot-end again, it seemed to be just as difficult (though easier at slightly higher temperature, hence trying that).
|The filament drive definitely wasn't gripping evenly; sometimes extruding, sometimes not. That made it difficult to calibrate...|
However, a short while into the print I noticed a couple of other problems; with the spring now making the filament drive tight enough, too much plastic was being extruded, making the extruder bump against layers of plastic in . I ended up sitting by the printer alternately using one hand to hold the carriage onto the rails, and the other to draft this post, for nearly 2 hours. That's not something I want to do again in a hurry.
|When we talk about repetitive labour...|
|Wire twist - easily installed with one hand (obviously I took this picture afterwards)|
Eventually I got this result:
|Fugly and stringy (until I cleaned it up, then just fugly... but usable)|
|It works... what more do you want?|
|The new carriage has mounting holes for both this tiny 32mm fan, or a 40mm one :)|
Good news on a design front though... I've finally got round to starting to do some CAD on printable parts for a cowled wind turbine, having only had ideas for it stuck in my head and a few scrawled sketches so far, while a group in Michigan Tech Uni have made what sounds like a better attempt at a relatively cheap plastic recycler/extruder, for which I hadn't thought of a good way to drive filament through yet, after mentioning the work of Delft Uni students before. So if their system works well and is easy to source parts for, I might not have to worry about that anymore. :)
I've also recently met someone else through TZM who seems interested in coordinating a project to start prototyping DIY rotary-hydroponics solutions into something we know works and is easy to build, which we hope can get the assistance of Douglas Mallette, as I hear he's also interested in developing that.