I am retrofitting two older printers with direct-drive bondtech feeders,

I am retrofitting two older printers with direct-drive bondtech feeders, and i was thinking about using E3D V6 hotends, but i do not like that there is nothing to lock the position of the heater block when switching nozzle, what i really like about the olsson block on my Ultimaker 2+ is that the heater block have a screw that prevents it from rotating during a nozzle change, so it is really easy to swap nozzles.

Is there any better alternatives in this respect?
I would like it to use E3D-style nozzles since that is what we got on every other printer

I don’t understand, just put a wrench around the heater block.

That’s what I do as well

The fact the UM2’s nozzle alignment screw holds the heater in alignment for nozzle switching is unintended though, because originally you couldn’t switch nozzles like that.

Wich is exactly what i would like to not have to do, since you need two hands to do it, and if someone are not careful (these printers reside in our Makerspace and are used by 100+ different people) you can pretty easily unscrew stuff and cause a leak, or even bend the heat break…

Have people bent the heat break while swapping nozzles or is that a perceived problem? The heat break is a lot tougher than it looks.

I’m not saying it wouldn’t be nicer if the design was different but I think the design would have to be very different. I don’t even know what to recommend. UM2 carriage is nice but has other drawbacks, and I think it’s fiddly in other ways.

@Jeff_DeMaagd , not on E3D hotends since we do not have any of those at the space yet, but both scenarios has happened on our Ultimaker Original which has a similar design. Also, it is very convinient to use a screwdriver with a 7mm socket and no wrenches to easily swap nozzles.

And yes, there is absolutely drawbacks with the UM2 printhead, but in this respect it is very user friendly. And about the screw, it is actually there to hold the heater block in place rotationally, even if the intended use did not include swapping nozzles but rather keeping the heater block from rotating when adjusting the stainless coupler that sets the height of the nozzle.

I think that you might be trading one problem for another. In the one wrench situation, you transfer the torque to the carriage, smooth rods, and frame - all of which can be damaged or knocked out of square/alignment. With two wrenches the torque is cancelled and the twisting of the carriage, rods, and frame is eliminated. Makerspaces offer unique problems…

Yes, Makerspaces does offer a very unique set of problems, it is like a kind of accelerated testing that often show failure modes that you would never find when using the same machines yourself :slight_smile:

Honestly it is hard enough to teach everyone that they need to heat up the hotend before replacing nozzles, to get everyone to use two wrenches correctly is not a thing i am looking forward to. On the Ultimaker Original which need that we have just said that it should not have its nozzle replaced by anyone since the heat break got bent and needed replacement.

I am not particularly worried about the frame twisting, it has not been a problem on our four Ultimaker’s and the printers i am retrofitting right now have pretty heavy duty frames, but it seems like there is no hotends designed this way i can find… i might have to make a custom heat block or something…

Well, personal experience with actual E3D heat breaks is they’re incredibly tough. I’ve had many kg of carriage pressing the E3D down to the bed and it still survived. I think a v6 could be modified but I’d have to take a look at their drawings. Edit: it looks doable, I’d have to think of a good insulator to prevent too much heat wicking away to the barrel. Wouldn’t need to modify the heater block, just use a longer heater clamp screw.