How to replace nozzle?

I have a Robo 3D+ and I'm wondering how you all go about replacing the print nozzles. I recently had a bad jam and I needed to remove the extruder assembly to clear it. I have a nozzle from MicroSwiss and I thought I'd try it out to see what sort of difference it made in my prints. So, with the extruder removed and heated up to 210C I grabbed the 'square' part (the part with the heater and thermistor) with some pliers and then tried to turn the nozzle with another pair of pliers. The nozzle wouldn't budge. I realize the nozzle starts to cool down pretty quickly once I grab it with the pliers, so I heated it up some more (~250C) and quickly tried to turn it. Still nothing. I cranked on it as hard as I could but it just seems to be frozen in there.

Has anyone else had a similar problem? How did you finally get the nozzle out?

 

Thank you both for the replies. I'll get a wrench or small ratchet driver and give it a try.

 

Thanks for this info. A related question - my nozzle was underextruding, so I took it out to try to see if it needed cleaning out. I managed to unscrew the heat sink (I believe that's what it's called - the part above the heater block), and ran some thin wire through it (couldn't get the wire to fit through the nozzle unfortunately). It did feel a little tighter than I thought it should, like filament was gunked up in there. I screwed it back on, and now I can't even get filament to extrude at all, it feels like the filament isn't even getting to the heater block/nozzle. I did heat it back up to screw the heat sink back on, but I'm wondering if I didn't screw it on tightly enough, or possibly too tightly - are those possible, or do you think I have another problem?

If I'm able to get the nozzle off, what is the best way to clean PET-G off? Acetone, or something else?

Also, re:underextrusion, my printer was working great until I changed filament, and I put more oil in my oiler. I think I put too much, could that have caused underextrusion? I am printing in PET-G, and I know it's PLA that absolutely needs an oiler, but I think I've read that it's no problem to oil when using PET-G too. But is it possible to use too much oil?


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Thanks Mark. So by baking the nozzle, you mean just stick it in an oven at 500 degrees Fahrenheit (that's close to 250 C) and all the PET-G will melt off the inside and outside?

Any other thoughts on why filament isn't going through to my nozzle, or why I was underextruding in the first place?

 

I haven't, so once I get something coming through the nozzle I'll do that.

But it was working just fine (at least to my satisfaction, even if not properly calibrated) for a lot of prints - would it all of a sudden just go out of calibration?

 

Thanks. Do you have a recommendation (and link) on which nozzles to buy? How often do you change your nozzle - only when it gets clogged, or do you make a habit of changing it regularly?

 

Mark, I have taken my heat sink back off of my extruder, and it feels like there is a clog in there. Can I bake the heat sink in the oven at 500 degrees as well, to melt the filament in there?

 

Great. I'm having trouble getting my nozzle off, like the original poster, even at 240 C. Those thermistor and heater core wires get in the way of my wrenches!

 

There is a red wax ring at the top of the heat sink (the side closest to the two screws where you insert the filament) - I'm assuming this will melt in the oven, is that okay?

 

So I was able to burn out the filament from the heat sink, and the red wax didn't melt off. What is that stuff?

 

Thanks. I was wrong - even after an hour or so of trying to clean the old filament out, it's still gunked up too much for the filament to go in. Plus it looks like I bent the heat break where it screws into the heater block. I think I'm going to switch to the E3D V6.