How to change nozzles (do I trust the site or the manual?)

I’m trying to figure out how nozzle changes should be done. The manual and the lulzbot store nozzle description contradict each other pretty seriously.

The manual (http://download.lulzbot.com/TAZ/documentation/current/LulzBot_TAZ-User_Manual-ebook.pdf) states:

In most cases the nozzle is best changed when the hot end is slightly warm. NEVER try to remove the nozzle when the hot end is at extrusion temperature. At higher temperatures the threaded extension expands in the nozzle causing the nozzle to bind if turned. Heat the hot end to 90-100C. This will soften the plastic inside the hot end and allow the nozzle to be turned o of the threaded extension.

And the website (at i.e. http://www.lulzbot.com/?q=products/budaschnozzle-20-nozzle-075mm) states:

If you have already printed with your Budaschnozzle you will need to loosen the nozzle after the hot end has reached 160C. Unless heated past 160C, any ABS/PLA on the threads will influence how easily the items can be moved. Removing the nozzle with the hot end cold, with the presence of plastic on the threads can potentially damage the nozzle threads/threaded extension

When re-installing the nozzle, slightly thread the nozzle onto the threaded extension, only one thread then set the hot end temperature to 160C. Once the hot end has reached 160C finish installing the nozzle.

:open_mouth:

For those who have successfully been doing nozzle changes, I would be very grateful if you could describe how you do it (and what type of plastic you were printing, etc).

…anyway, I don’t know if this is right or not - if anyone with more experience would like to comment, I would be very grateful - but when I tried to follow the directions given by the manual, well… let’s just say it didn’t go well for the budaschnozzle. :frowning:

I just now had my first try on the directions given on the nozzle product page instead (heating the nozzle to 160C), and that went smoothly.

In between, and this could be what’s making the difference versus anything else, I also started putting high-temperature anti-seize (http://www.amazon.com/gp/product/B008RMT9LO/ref=oh_details_o00_s01_i01?ie=UTF8&psc=1) on the threads before putting any plastic through any nozzle.

We’ve changed the recommendation in the manual regarding nozzle changes. The changes should be live in the next hour or so. We recommend heating the nozzle to 160C and removing when still warm. We are updating the TAZ user manual and are posting the changes here: https://www.lulzbot.com/?q=support/taz-user-manual-updates-and-errata. As we update the current TAZ user manual we will update the manual found here: http://download.lulzbot.com/TAZ/documentation/current/. Thank you for pointing that out!

No problem - and thank you for responding so quickly! I would add, while you are updating that section of the manual, to note the clockwise vs. counter-clockwise issue I mentioned earlier as well. If you are heating the nozzle to change it, then it’s attached, and you are definitely turning it clockwise, rather than the opposite.