Dual extrusion mod for C2

The aluminum plate is a sweet piece of CNC work. Shame to hide it



The URL silk screened on the boards is non-functional (hey! I had to look)

 

And at last this shows that octoprint sees both extruders and can heat them appropriately.



There was an interesting bug that I have raised to Robo where only in the LCD, if you tell it to heat extruder 1 then extruder 1 heats. If you tell it to heat extruder 2 then extruder 1 heats From other software (not the LCD) everything works as expected (but we were pulling out hair out at first trying to sort that... "Its Marlin, no wait... the control board! no wait...")...

At least it picked up the second extuder correctly. Test prints we did with the single extruder while the second was installed, but not used, were fine No layer collision with the new extruder so the Z offset appears to be the same on both nozzles. We redid the Z leveling and it was pretty much identical to before (-5.8)

 

I will be glad to upload my configuration.h file for reference.
Last steps were to refresh the EEPROM (M502 and M500)

I am waiting on the JST connectors to arrive so that I can replace the 24 gauge wire with 18 and this project is finished

Still have to work on calibration and fine tuning, but the work in the guts of the printer is done

 

The connectors involved with the C2/Robo electronics should be these:
https://www.digikey.com/product-detail/en/jst-sales-america-inc/EHR-2/455-1000-ND/527224

and these pins:
https://www.digikey.com/product-detail/en/jst-sales-america-inc/SEH-001T-P0.6/455-1042-1-ND/527266


EDIT: These are a perfect fit.

 

Something else that RoboHQ was kind enough to point out (and that we totally saw and should not have ignored) the voltage to the heater cores is 19v. So we do not want to use a 12v heater core. It worked, briefly, but it would tend to overload the source power supply. I am looking into to either use of 24v ones or just sourcing the correct one from Robo (which saves having to fab a connector).

 

The new robos are all 24v??? Or just the heater cores ?

 

The power supply is 19v I would imagine (edit: I will go check and be sure)

I am pretty sure everything electrical/electronic is sourced at that voltage (well, not the Pi that has to be stepped down, but likely their control board uses 19v)
.
I have not analyzed the circuitry but worst case you run the power supply at 19v and step down where you need it.

Many of the other 3D printers are 24v so it is not a surprising alteration. We noticed it and just blew right past it and it really should have tickled some of my brain cells awake.

 

Good info! Thank you, a but surprised they went up to 24(19) after being 12v but then again a whole different style

 

There are decided benefits to the higher voltage and I am sure that it what pushed them to make that change.

I will look at it and see what the P/S is sourcing today (it may be multiple outputs).

edit: Yes, the brick that powers it is putting out 19vdc and that plugs into the control board.

I will have the JST connectors end of this week and will come back and finish this then.
For the time being the only way to properly control the second extruder is from external host programs (OctoPrint, MatterControl, etc.) not via the LCD. This may change at some point.

 

JST connectors and 24v heater core are in so I will wrap this up over the weekend.

 

OK, everything is correctly wired 24v heater core used for second extruder and JST connectors installed along with a heavier gauge wire for the power loop from the top of the platform to the lower board. That is no longer getting hot either (the wire itself). Not sure if that is due to the slightly heavier gauge or the 24v heater core Maybe a little of both.

Now righteously struggling with getting the extruders to behave together in a dual-extruder configuration. I am sure it is just the slicer (Simplify3D) that I am fighting with and I will probably bounce a question off of them if I can't sort it. Electrically and mechanically it is working correctly.

 

If you have dual extruders and you use Simplify3D and you DON'T run the dual extrusion wizard... you're asking for trouble

 

Also, after replacing the 12v heater core with a 24v heater core, replacing the wires that jump from the top board down to the bottom with the extruder power (used a slightly larger gauge) and using the correct JST connectors for everything, there is no more over heating of wires. Some caveats...

You really can't do much with the two extruders from the LCD since the Raspberry Pi code is (apparently) locked to a single extruder. It sees them both, but many things are non-functional in silly ways since using the LCD to heat the second extruder will only heat the first, etc.

I am working with RoboHQ to address that, but it is worth mentioning that this was not a configuration (dual extruder C2) that they ever said would work. The second extruder is fully functional via the firmware and can be controlled with the slicer or OctoPrint.

 

The only way to perfect the Z level on this is to raise the bed to where the nozzles (or the lowest one) is barely touching it (verify with sheet of paper) then release the screw that holds the two in-place. they will then both "drop" however far that is to rest on the sheet of paper and then you retighten the bolt that holds them in-place. They are now effectively zeroed at the same spot WRT Z axis. Not that they were far off (same extruder, etc.) but now they are perfect.

 

Don't forget you will need to do this every time you replace a nozzle or both, so it's not quite set and forget.

 

I was trying to keep it cheap
There already was a Hexagon installed so adding a second one was cheaper than dual prometheus... Not a bad idea, but still trying to get this slicing and dicing happily at the moment. The hardware seems to be working fine, but I am struggling with the software side of getting dual extruders happy.

 

You could always do a single promethius with a promethius system dual extruders one nozzle, just with dual extrusion cut your bed size in half for a prime tower(unless you use an ooze shield)...its a pain lol