E3D Nozzle Swap - PRUSA Instructions vs E3D  

RE: E3D Nozzle Swap - PRUSA Instructions vs E3D

The most important bit is to do final tightening at 285C so everything is expanded fully and will contract to form a good seal when printing at lower temps. Everything prior to that is either removal (in which case, as long as it'll turn, you're good) or hand tightening in preparation for the final step (which isn't critical). I do heat mine up to remove nozzles as it helps loosen them up a bit if there's built-up crud in the way. I do a clean at the same time & temp.

RE: E3D Nozzle Swap - PRUSA Instructions vs E3D

Posted by: @bobstro

The most important bit is to do final tightening at 285C so everything is expanded fully and will contract to form a good seal when printing at lower temps. Everything prior to that is either removal (in which case, as long as it'll turn, you're good) or hand tightening in preparation for the final step (which isn't critical). I do heat mine up to remove nozzles as it helps loosen them up a bit if there's built-up crud in the way. I do a clean at the same time & temp.

Thanks! I figured it was probably not critical, just something I noticed while reading up on how everything is put together. 

RE: E3D Nozzle Swap - PRUSA Instructions vs E3D

This post is kindda coincidental, as I've been having a circular conversion with E3D. I'm looking to install a V6 in my Sovol. My point is that they have this two stage process involving initially setting the max nozzle temperature in firmware to 300C so that you set nozzle to 285C (marlin deducts 15C) to hot tighten. They say "Hot-tightening is essential to sealing the nozzle and heatbreak together" The process of hot tightening "Gently tighten the nozzle whilst holding the heater block still with a spanner and using a smaller 7mm spanner to tighten the nozzle."

My question - is it necessary to use this hot-tighten process when making a routine nozzle swap. They say no but when I pointed out that the mechanical part of hot tightening is exactly that same as a routine nozzle swap ie hold the block still and tighten the nozzle. At this point the discussion becomes circular and they say you have to set the temp to 285C ......

So the question remains, why do I have set the temperature higher than normal the first time I tighten the nozzle against the heatbreak but not on any subsequent time I tighten the nozzle against the heatbreak ie routine nozzle change.

RE: E3D Nozzle Swap - PRUSA Instructions vs E3D

Posted by: @towlerg

[...] So the question remains, why do I have set the temperature higher than normal the first time I tighten the nozzle against the heatbreak but not on any subsequent time I tighten the nozzle against the heatbreak ie routine nozzle change.

No idea what E3D's support logic is, but if I don't tighten the nozzle while heated every time, there's a good chance of a leak. I just observe and modify procedures until they work for me, so YMMV.

RE: E3D Nozzle Swap - PRUSA Instructions vs E3D

Posted by: @bobstro

Posted by: @towlerg

[...] So the question remains, why do I have set the temperature higher than normal the first time I tighten the nozzle against the heatbreak but not on any subsequent time I tighten the nozzle against the heatbreak ie routine nozzle change.

No idea what E3D's support logic is, but if I don't tighten the nozzle while heated every time, there's a good chance of a leak. I just observe and modify procedures until they work for me, so YMMV.

 

Are you using a in lb torque wrench by change or just doing a guestimate on tightness. I was thinking of getting a torque wrench to take the guess work out. 

RE: E3D Nozzle Swap - PRUSA Instructions vs E3D

just walked in on this as I just changed my nozzle today. Swapped out the 0.4 for a 0.6. Followed the Prusa instructions as such to heat and remove the old one and fit the new one whilst hot.

Tightened up by eye and feel, popped it all back together and printed off an XYZ calibration cube. Perfect to within 0.01 of a mm. not going to grumble about that after worrying about Z layer calibration etc because of changing out the nozzle and possibly affecting the height. 

Why I never swapped to a bigger nozzle to print out all the parts for a Lack Enclosure and Dry Boxes earlier! Cuts printing time to less than half. 🙂

RE: E3D Nozzle Swap - PRUSA Instructions vs E3D

Torque at temp - always.

Why? The heater block is aluminum, and is what locks everything in place. Aluminum has a high thermal coefficient of expansion. If you torque at room temp, the block swells at 215 and the nozzle and heat break are essentially free to wiggle loose because that room temp torque is gone. 

α Al 23
α Br 18
α Ss 15

ps: Not exactly true with a copper heater block ... but probably still a good idea.

α Cu 16

RE: E3D Nozzle Swap - PRUSA Instructions vs E3D

Posted by: @tim-m30

[...] ps: Not exactly true with a copper heater block ... but probably still a good idea.

α Cu 16

Interesting detail. Got numbers for titanium (heatbreak) and tungsten carbide (nozzles)?

RE: E3D Nozzle Swap - PRUSA Instructions vs E3D

Too lazy to dig out my Eshbach's ... 

https://www.engineeringtoolbox.com/linear-expansion-coefficients-d_95.html

RE: E3D Nozzle Swap - PRUSA Instructions vs E3D

Curiosity ... since I am installing exactly those things soon.

α Titanium ~8 [yikes - must heat to tighten]
α Tungsten Carbide ~4.4  [triple yikes ... is 280c enough?] 

RE: E3D Nozzle Swap - PRUSA Instructions vs E3D

Posted by: @rythomas

I swapped my nozzle recently and noticed there was a small difference in the nozzle swap video from Prusa vs E3Ds instructions. In the E3D instructions it has you loosen and tighten the block while still cold and only remove / insert the new nozzle while heated to 285C. In the PRUSA instructions it has you do everything with the block and nozzle while being heated to 285C. Was just curious if one way was more correct. 

I think there is an English-English translation problem. E3D doesn't want you to burn your fingers so has you do the first loosen and last tighten at temp, all other work is done cold.  Prusa omits the burnt fingers worry part and ignores doing any cooldown during the swap process. 

It's that old question of "What happens if I touch that pretty blue flame?" asks the kid; "Don't know," says the older kid: "touch it and find out." Well, at least the story establishes a line of trust.

RE: E3D Nozzle Swap - PRUSA Instructions vs E3D

@tim-m30 and bobstro

On initial install E3D specify that a firmware change be made to allow the heater block up to 285C and then after "hot tightening" modify the firmware back to 270C. My question is why do I need the firmware change on initial hot tightening but not on any subsequent hot tightening given that the mechanical process is exactly the same?

I understand the need for hot tightening, I just don't understand why initial is different than subsequent.

RE: E3D Nozzle Swap - PRUSA Instructions vs E3D

If this is a mini - I'll simply say I know NOTHINGK!

But the mechanical issues involved do not change. Every time you swap a nozzle, you MUST heat the hot end as high as you can, safely. For an E3D-V6, that value is 285c.  You do not want to keep the nozzle that hot because it deteriorates the plastic and other components like the heater and the thermistor - so E3D suggests cooling things down between steps. 

If the MINI has a temp limit of 270c, it's likely Prusa knows something bad will happen at 285c. And since the MINI is entry level, users will use 285c during normal operations then complain the printer broke -- despite warnings in the manual.  "If you allow 285c then it should work at 285c!!! I want my money back!!" 

Personally, if there is s firmware limitation, I'd keep the 'unlimited' version installed for convenience. Though, I'd not complain if the printer went south because I abused it using 285c to print Polycarbonate like others might.

ps: where in the documentation does it say you need to do this change only once? Point to a page in the manual or provide a web link where you are reading this.

RE: E3D Nozzle Swap - PRUSA Instructions vs E3D

@tim-m30

"ps: where in the documentation does it say you need to do this change only once? Point to a page in the manual or provide a web link where you are reading this." I asked E3D if it was necessary and they said no, just on initial hot tighten.

By the way as I'm sure you know but perhaps peeps following this thread may not, the limitation of max 285C is caused by the standard thermistor.

RE: E3D Nozzle Swap - PRUSA Instructions vs E3D

@towlerg

So nothing in writing says "you only need to tighten at 285c the first install."  I wasn't there to hear what the tech told you, but I'd ascertain there was a miscommunication. He didn't understand what you were asking, or you didn't understand the context of what he was saying. 

"Only tighten the nozzle at 285c once/one time." has many meanings in English.

E.g., when torqueing any fastener, you only torque it one time. That means, you use a torque wrench and turn the screw/bolt/nut until the torque reads xyz inch pounds, foot pounds newton meters etc.  You do not go through and retorque it a second time because that will over tighten the screw/bolt/nut.  There are exceptions, certain high torque bolts in an engine and machinery require torqueing down in stages. 

Or, it might mean something else entirely, like if you torque the screw once, you never ever need to tighten it again. Well, until you replace it.

Or, it might mean you tighten it once and the next time you work on it you don't really have to care how much torque you put on it because it doesn't matter if it is loose.  -- note: this interpretation doesn't make a whole lot of sense.

Any time I change nozzles, I always torque the nozzle / heat break to 285c. 

--

As for the thermal limits: yes - above 285c you need a different sensor. A platinum sensor is a common go-to upgrade part, but requires an amplifier to buffer its output, and a firmware mod to set the temperature table to the PT linear range [there are lengthy forum threads on making this change].

RE: E3D Nozzle Swap - PRUSA Instructions vs E3D

@tim-m30

Here's an emailed question and E3D's response. Perhaps my question was unclear

George Towler Oct 22, 2020, 14:57 GMT+1 Hi, just looking at the firmware change for initial tighten nozzle on install. Is it necessary to follow same procedure when changing nozzle in normal use?

RE: E3D Nozzle Swap - PRUSA Instructions vs E3D

I read that response as if changing the type of extruder fitted to the printer. Ie changing from a e3d v6 to something like a bond tech or a mosquito. Of course you didn’t include your original question to give context to the answer tech support gave you. 

RE: E3D Nozzle Swap - PRUSA Instructions vs E3D

Posted by: @towlerg

@tim-m30

Here's an emailed question and E3D's response. Perhaps my question was unclear

Towler Oct 22, 2020, 14:57 GMT+1 Hi, just looking at the firmware change for initial tighten nozzle on install. Is it necessary to follow same procedure when changing nozzle in normal use?

 

Kovala (E3D Online) Oct 22, 2020, 18:30 GMT+1 Hello George, Thank you for your inquiry. Nozzle tightening does not require a firmware change or update.  Replacing or changing an extruder does.  If you are only changing the nozzle that will have no effect on your settings and will not require a firmware change. Let us know if we can be of further assistance. Many thanks, Keith Kovala E3D Support Agent.

What does firmware have to do with changing nozzles?

So again, an English-English translation problem.  The tech was probably thinking "Are you doing a routine E3D-V6-0.4 to E3D-V6-0.6 nozzle swap (dimensionally identical except bore); or are you changing from an E3D nozzle to brand Z nozzle that is a few mm longer?

In any case, E3D is telling you you do not need to change firmware when changing the nozzle. They are aren't saying anything about tightening at temperature.

RE: E3D Nozzle Swap - PRUSA Instructions vs E3D

Said another way, when I load my copper nozzle, I do not change firmware. When I load my tungsten nozzle, I do not change firmware.  However in both cases I loosen and tighten them at 285c.  When I change back to my brass nozzle, again, I loosen and tighten at 285c.