After messing with this add on for the last few weeks, somewhere north of probably 30-40 hours of attempts with it sometimes working and sometimes randomly failing even when nothing has been changed from one print to the next. It's simply too frustrating.
When the device works, it's amazing and I want to tell the world about it. But the problem is it won't work most of the time. Every time I fix an issue another pops up.
I've tested and adjusted so many things that while I'm sitting here trying to list the things I've had problems with I can't grab one thought out of the flurry, but I'll try, in no particular order.
The Y adapter is quite frustrating and causes so many issues of getting jammed in one direction or the other. I have mostly fixed this by loosening the screws on it by half a turn, as I found suggested in one thread here on the forum. But this fix only works sometimes and it will still get jammed in it. I have a Capricorn tube installed from the primary extruder to the hotend.
I can form beautiful tips when extracting the filament, sometimes. I haven't changed my extraction gcode in probably a week now and none of the tips are consistent and I have no idea why. I've tried different filament and different temps. The problem isn't getting a tipped formed, it's getting the same kind of tip repeatedly.
The final straw happened just a bit ago today, I haven't touched the extraction gcode in a while, as mentioned, and yet for some random reason the printers primary extruder didn't extract the filament all the way. It literally pulled it all the way out just fine earlier today and with no changes just randomly didn't, it left about 50mm or so in the Capricorn tube. So another print failed, that's three failed prints today, unknown number of failed prints over three weeks or so.
The control box for the unit has a really weird bug too that has driven me insane a few times. If for any reason the switch is pressed for more than 6 seconds or so, the entire device freezes up until it's unplugged, which obviously fails the print. This is problematic when it needs to be pressed for 5.5 seconds and the button is capable of being shifted ever so slightly when pressed sometimes. Again the key word being sometimes here.
My suggestion to improve the product is this; remove the printers primary extruder, have one extruder for each of the four colors you want, these all feed into a four way splitter that is not Y's stacked, but a true 4 into 1 meeting. Have the mother boards ribbon cable that controls the printers normal extruder (that is now removed) to a four way splitter. Each of these ends goes to a 4 pole relay that is controlled by the products unit. The switch that the unit uses to select which filament to feed is instead switching which relay is active, and therefore which extruder the motherboard controls and the true four way reduces the need to shape the tip so accurately. These would exponentially increase the consistency of the unit and therefore the ability to make adjustments that stick while also simplifying the overall control process. I've been an electrical engineer for 7 years, I'm probably just going to try and implement this myself, but if you'd like to make a mk3 with this, by all means please do.