user978537432

In answer to my own question, it seems the default state after aborting is always extruder 1, so just physically plucking the second extruder off and putting it back in the dock before starting a print works.

Also a more specific question: I've noticed that when aborting a print, it can mess up which extruder the printer thinks is currently in use. This results in having to swap extruders in reverse order ('picking up' extruder 2 when it's already picked up or 'dropping' it off when it's already docked), resulting in banging against the dock uncerimoniously. In order to avoid the needless wear and tear, how can I view and change the current extruder electronically without performing the physical swapping procedure?

Just finished the upgrade on my UM2Ext+ (UM2+Ext?) using the expansion board kit from aliexpress. The kit was missing several bolts, nuts and wires, and the magnets are much too weak as has been noted by others, but the circuit board works perfectly. After getting all the extra bits and pieces the instructions were pretty straight-forward. I chose to drill holes on the back of the printer to attach the expansion board mounting frame as the 2nd head fan connecter is too short to reach the bottom of the printer. So far everything is working perfectly and I'm happily printing with dissolvable supports. However, I've noticed that dual nozzle support for any kind of bed adhesion is sketchy at best. I've done some tests using default starting values in cura and a basic cylinder test model: Skirt: When selecting extruder 1 for the object and extruder 2 for printing a skirt, the second nozzle is simply outright ignored, and nozzle 1 prints everything. When swapping, selecting extruder 2 for the object and extruder 1 for printing the skirt, extruder 1 begins printing the skirt, then extruder 2 comes in half-way through and finishes printing the skirt. It also seems that the numer of lines is double what I selected in Cura in both scenarios. Brim: When extruder 1 prints the part and extruder 2 prints the brim, again, the second nozzle is completely ignored. Also, the number of lines in the brim is double what I selected. When extruder 1 prints the brim and extruder 2 prints the part, extruder 1 sucessfully prints the brim as directed, however, extruder 2 comes in, prints an additional 3 lines of brim on the outside, then proceeds to print the part. Raft: Again, if extruder 1 is selected for the object and extruder 2 for the raft, everything gets printed only with extruder 1. When extruder 1 is selected for the raft and extruder 2 for the object...it works, actually.

Yes, that worked, thanks so much. I just doubled the default purge amount from 10mm to 20mm and added a retract to clip the prime blob and the first layer of Marlin now works great. For any googlers out there, here's what I did (changes from default settings in bold, edit the textbox in machine settings labelled "start g-code") : I'm sure I can figure out some tweaks to get marlin volumetric working too.

So I just installed a brand new linux mint OS on a completely different laptop, installed a brand new instance of the latest cura and, again, using completely identical settings for all 3, compiled to ultigcode, marlin and marlin (volumetric). I made no tweaks whatsoever, this is cura's own Ultimaker 2+ Ext default settings out-of-the-box. I allowed each to print 1 layer of an overhang test. The results are as follows: Utligcode (correct outcome): Marlin (severe underextrusion): Marlin volumetric (severe overextrusion): Note: marlin was printed FIRST, after a reset of the machine, so that appears to make no difference.

In the gcode generated by cura, both marlin and reprap extrude only a tiny fraction of filament for each move compared to ultigcode. The difference is not constant (and yes I use identical material settings for both marlin and ultigcode) Below is a snippet of the ultigcode file which prints properly: Below is a snippet of a marlin file with identical material settings, identical profile, identical model, identical printer. This is only one of a list of problems that make marlin/reprap unusable on the UM2+. A single click on the "gcode flavour" dropdown in cura makes the entire file useless junk.

I need to print a temperature tower with an Ultimaker 2+ Ext, which is impossible with 'ultigcode'. In order to change the temperature multiple times at custom layers, marlin or reprap are required, both of which are being completely rejected by the printer. Sometimes (but not always) the hotend fails to heat up, usually the first layer starts a full extra layer above the (levelled) bed, and it always fails to extrude anything. None of these behaviours occur with ultigcode. Something is massively wrong with how the UM2+ is reading (or refusing to) anything other than ultigcode. I have compiled the marlin/reprap files under several different versions of cura, dozens of different print profiles, attempted printing via usb and sd card, nothing at all works.