E3D v6 print head on ultimaker original

[JO3 1]

Hi All!

I'm in the process of wiring up an E3D v6 3mm bowden print head to my UMO, I'm using a printed head found on thingiverse here: http://www.thingiverse.com/thing:397518

I'm connecting 3 12v fans, one which needs to be always on, and two that run as normal side fans. I've done a sketch of how I think it should go. Electronics are definitely not my forte and I would rather not damage the circuit board, so please let me know if this looks wrong!

I'm connecting the thermistor and wiring that up and i want to know whether it's better to use a thermistor cartridge like: http://e3d-online.com/Thermistor-Cartridge?search=thermistor or a glass bead thermistor like: http://e3d-online.com/100k-Ohm-NTC-Thermistor-Semitec?search=thermistor I'm not sure which would be easier to wire.

Any help would be very much appreciated!

[gr5 2,167]

The thermister part scares me the most. You dont' want to continue using the existing thermocouple and AD595? I thought these thermistors don't do so well at temperatures above 200C but I'm not certain. Anyway you'll have to build your own custom firmware if you switch to a thermister and insert a 4.7K pullup in the circuit board (there are holes for that ready to go). Here's a great custom firmware builder:

https://bultimaker.bulles.eu/

But notice that even the thingiverse link you point out still uses the original thermocouple that comes with the UMO. I really recommend sticking with that method.

Also note that thermocouples are all identical no matter who the manufacturer. Same with PT100 temp sensors (not supported by older UMO electronics) but thermistors are crazy different from manufacturer to manufacturer. A "100K thermister" from one company might have a different curve than the next company although I suppose all 104GT-2 might be the same. Not sure.

Finally and probably most important of all - all metal hot ends kind of suck with PLA. They are great for other materials like ABS but for PLA - the semi-molten PLA sticks to the metal and everything is fine until you go to do a second print and you can't get the PLA to move up or down. Or in the middle of a print with lots of retractions the PLA gets stuck and the print is ruined. It's not a problem where the metal is colder than 40C. Not a problem where the metal is > 150C. It's the in between area where the UMO has teflon. But if you are certain you will NEVER print PLA ever again the e3d hot end is fantastic.

[JO3 1]

Thank you so much for your reply! Really helped out a lot.

I'm using the original thermocouple as I don't fancy changing the firmware.

Also thanks for the advice in using PLA, once I've got it set up I'll try printing with ABS and see how it goes.

[zoev89 73]

Results with the E3D using PLA is intermittent. Some people have issues I usually don't have issues with PLA. But I have to admit that before I change material I put a drop of sunflower oil on the filament before inserting it in the hotend and it is good to go for at least 12h printing. It might also depend on the kind of PLA I am using Colorfab which is quite tacky on the outside and it rubs on the side on the cooler.

And switching back from ABS to PLA make sure to do a couple of hot pulls to get all the ABS out since the lower print temperature of PLA can give issues if the is some ABS residual (same is true for colorfab XT as well).

I have printed quite a bit with V6 and PLA.

[zoev89 73]

Oh I hate this automatic logout feature on the forum.. I just typed a reply and then it logged me out so the message is lost:angry:

For the always on fan your proposal is ok.

For your cooling fan it will not work. The problem is you loose your speed control. You will find that it has difficulty with starting up and then will spin up to max rpm and that is not what you want.

Fortunately there are simple solutions. For example you can use 11 diodes (1N4001) in series or use a 6.8V 1W zener diode. In both cases you loose a constant voltage whatever the current is. So at low rpm the motor will draw more current (it is using pulse width modulation) and with increased fan setting it will draw less current (higher rpm results in more voltage from the motor) Here is where your resistor has issues at a low setting the current is relatively high so it will drop quite a bit and then when the motor spins up it will draw less current so your resistor will drop less resulting in non starting motor at low setting to spin up to max rpm. Here the diodes or a zener works better since they always drop the same amount of voltage not mater the amount of current.

[JO3 1]

Thank you for your reply, I ordered a few zener diodes a while ago as another option, they are 1W 6.2V, do you think these will do the trick?

[zoev89 73]

Well typically the zeners drop a little more when drawing current then exactly specified and the fans might not blow up directly when a little more then 12V is supplied. I would test it out and measure how much voltage is on the fan when the fan is directly connected to the 19V. If you want to add some margin just add an extra diode (if you have enough zeners you can use a extra one in the opposite direction) .

For safety I would use 1 zener (or set) per fan and check how hot the zener gets.