Fixation of throat in hotend

Blue21
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Joined: Sat Jun 06, 2020 8:04 am
Location: Switzerland

Fixation of throat in hotend

Postby Blue21 » Sat Mar 20, 2021 9:48 pm

I purchase a new set of hotends (left and right) after some issues and noticed that they were not exactly same as original.
There is a brown glue or something like that around the thread entry, see bellow picture.
2021-03-20 22.32.35.jpg


My questions are:
1) What is this "glue" ?
2) What is its purpose ? Does it lock the throat to alu block (like a Loctite thread lock) ?
3) Is it still possible to remove the throat for cleaning the interface between the throat and the nozzle ?

Thanks in advance for any advise.
E2 + Prusa Mini <- UM 2+ <- Replicator2

Blue21
Posts: 150
Joined: Sat Jun 06, 2020 8:04 am
Location: Switzerland

Re: Fixation of throat in hotend

Postby Blue21 » Wed Mar 24, 2021 4:09 pm

Update, after purchasing a new right hotend, the left was still working on some print during the rework of the right extruder (just left the thermocouple connected so it didn't goes in error mode).

The print finished but there was ongoing same horror issue as I had with the right one, hot filament was leaking from the top of the hotend, where I noticed the mentioned brown "glue" on the new hotend.

2021-03-24 14.59.54.jpg

2021-03-24 14.59.49.jpg


So the questions remains, can we remove the throat for cleaning or it should remain in place ?
Is the "brown glue" to be replaced ? What is it ?

Any advise from Raise3D would be appreciated.
E2 + Prusa Mini <- UM 2+ <- Replicator2

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ccclarke
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Re: Fixation of throat in hotend

Postby ccclarke » Wed Mar 24, 2021 8:18 pm

Just went through the same experience - only a little larger. Was greeted by a fist-sized glob of plastic encapsulating the entire left side hot end when I arrived at work on Monday morning.

Yours looks like a typical throat leak. To remove the majority of the plastic, I use a heat gun with the hot end blocked in a vise. Once the plastic softens, it's easy to remove most of it. The rest will be softened by immersing overnight in a covered glass beaker of acetone. Use cotton swabs or paper towels to wipe it off.

Remove the nozzle first - not the throat, followed by the thermocouple and heater rod. If the throat is still hard to remove, return it to the acetone bath and it should loosen up after a few hours. Do not force the throat out or you run the danger of it yielding - the inner wall of the lower section is very thin.

Once it's out, clean the upper and lower threaded portions of the heater block and bores for the thermocouple and heater rod with cotton swabs. Dry fit the components to ensure the surfaces are clean and smooth.

Follow the nozzle install procedure. I always install the nozzle first, then the throat before I tighten the nozzle so the chamfered ends mate tightly to prevent leaks. For the Pro2, I set the nozzle tip to throat end distance to a little less than 34mm, since the procedure is subjective -"Leave a small gap between the nozzle and the heater block. . . " Five mm works well. Once I started measuring the completed assembly, I haven't had a leak. You may need to experiment with the E2 to find the happy zone, but record it for posterity, or better yet, re-write the procedure using measurements instead of Raise3D's adjectives and refer to it going forward.
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Blue21
Posts: 150
Joined: Sat Jun 06, 2020 8:04 am
Location: Switzerland

Re: Fixation of throat in hotend

Postby Blue21 » Wed Mar 24, 2021 10:54 pm

I feel your pain, I was lucky on this one as the print just finished with top surface ironing, maybe the flow was too high and increased the pressure in the hotend at that moment.
Yes the procedure is not that clear and I started to write my own so that it can be repeated, including incident repair :)

Thanks for the advise regarding the assembly, it is true that some measurable values are needed.
What kind of temperature do you use when tightening the nozzle ? I currently had the issue with PETG at 250°C but I think when I tight the nozzle I was more at 210°C for PLA, not really sure if that can make a difference but maybe the higher the better.
E2 + Prusa Mini <- UM 2+ <- Replicator2

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ccclarke
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Re: Fixation of throat in hotend

Postby ccclarke » Thu Mar 25, 2021 9:01 pm

I insert the throat to a specified measurement in the block, then tighten the nozzle until it contacts the chamfered bottom of the throat, then double-check the nozzle to throat upper surface measurement to ensure it is <34mm. 33.8mm is nominal. I perform this assembly cold, since the parts will expand slightly when heated. Using this method, I've never had another leak from the throat or nozzle.

Raise3D's procedure has you disassemble everything hot, but after unloading the filament, and dropping the hot end from the extruder, I use a heat gun with the block in a vise. It's a lot easier to access everything, rather than holding the assembly with a giant furry heat-resistant glove in the enclosed build area.

CCC
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Steven@Raise3D
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Re: Fixation of throat in hotend

Postby Steven@Raise3D » Fri Mar 26, 2021 1:00 am

I would suggest creating a support ticket so that one of our technical support engineers can better assist you in solving this issue.



Blue21 wrote:Update, after purchasing a new right hotend, the left was still working on some print during the rework of the right extruder (just left the thermocouple connected so it didn't goes in error mode).

The print finished but there was ongoing same horror issue as I had with the right one, hot filament was leaking from the top of the hotend, where I noticed the mentioned brown "glue" on the new hotend.

2021-03-24 14.59.54.jpg

2021-03-24 14.59.49.jpg


So the questions remains, can we remove the throat for cleaning or it should remain in place ?
Is the "brown glue" to be replaced ? What is it ?

Any advise from Raise3D would be appreciated.

Blue21
Posts: 150
Joined: Sat Jun 06, 2020 8:04 am
Location: Switzerland

Re: Fixation of throat in hotend

Postby Blue21 » Fri Mar 26, 2021 6:43 am

Steven@Raise3D wrote:I would suggest creating a support ticket so that one of our technical support engineers can better assist you in solving this issue.


I am not located in US, will it be accepted?
The previous one I made was rejected as I had to ask my reseller to ask Raise3d for the issue and then it would relay Raise3d answer to me.
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Steven@Raise3D
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Re: Fixation of throat in hotend

Postby Steven@Raise3D » Wed Mar 31, 2021 12:28 am

Blue21 wrote:
Steven@Raise3D wrote:I would suggest creating a support ticket so that one of our technical support engineers can better assist you in solving this issue.


I am not located in US, will it be accepted?
The previous one I made was rejected as I had to ask my reseller to ask Raise3d for the issue and then it would relay Raise3d answer to me.


For your particular issue, it appears that the hotend may be defective and will need to be replaced. As you are located in Europe you will need to go to your local distributor that you purchased the machine from for any type of RMA.

Vipao
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Re: Fixation of throat in hotend

Postby Vipao » Thu Apr 15, 2021 8:24 am

Steven@Raise3D wrote:
Blue21 wrote:
Steven@Raise3D wrote:I would suggest creating a support ticket so that one of our technical support engineers can better assist you in solving this issue.


I am not located in US, will it be accepted?
The previous one I made was rejected as I had to ask my reseller to ask Raise3d for the issue and then it would relay Raise3d answer to me.


For your particular issue, it appears that the hotend may be defective and will need to be replaced. As you are located in Europe you will need to go to your local distributor that you purchased the machine from for any type of RMA.


Same issuer for me... after 1500h of good printing on a 4,5 mounth old E2 I start having continuous cloggiung and extruder clicking on both head. In addition left model fan stop to work. Contacted my local distributor in Italy, cleaned machine, resetted to factory default, changed nozzle and made some test with Raise3d premium PLA without luck. Distibutor suggests me to change hotend at my own expense because not covered by warranty: he was not sure even if fan is under warranty...
Yesterday I installed a copperhead slice engineering with new E3D hight precsion heating cartridge and vanadium V6 Nozzle X on left printer head. Machine has never printed so good! Why pay my own 96€ (this is official price in Italy) for a standard Raise3D E2 hotend (knowing it has lot of problems...) when I can pay 130€ for a hotend that has really higher performance? In addition removing standard E2 hotend from printer head to install copperhead I found molded PLA leackage (I print only PLA) from top of hotend, where heatbreaker is inserted into heating block! It's clear there is a leackage as reported by many other users.
I'm quite diisappoinded... 3500€ machine, declared for professional use, lot of people with the same problem on hotend (and this suggest E2 hotend has some design problems...) and Raise continues to suggest to install the same hotend... waiting for another clogging or leackage? And in addition, answer for a known problem depends on the country you buy the machine! It's crazy!

Vipao
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Joined: Sat Nov 21, 2020 5:58 pm

Re: Fixation of throat in hotend

Postby Vipao » Sat Apr 17, 2021 9:45 am

Photos attached show leackage on top of E2 left hotend and some burns in model cooling fan. Only 4.5 mounth old machine ad 1500h of Pla printed. I shoulb be interested if someone of Raise3D staff should comment about... @Steven@Raise3D?

1618652025741.jpg

1618652025734.jpg

1618652025746.jpg

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ccclarke
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Re: Fixation of throat in hotend

Postby ccclarke » Sat Apr 17, 2021 11:56 am

Classic upper end leak. The throat wasn't positioned against the chamfered top of the nozzle tightly enough and eventually leaks around the thread interface at the top of the heater block.

Unless it is damaged, you probably don't need to replace the hot end, just clean it up, reassemble it properly and get back to printing.
First, remove the melted plastic on the exterior with a heat gun and scraper while blocking the hot end in a jeweler's vise. The nozzle can be removed with the hot end in a vise using an open end wrench, but all of the plastic around the threads of the throat must be removed since the throat inner diameter is so thin any excessive force will break it. If the throat won't budge, don't force it. Just get the nozzle off and perform the following:

Immerse the hot end (at least overnight) in acetone to soften the plastic. Once the throat is removed, I use an appropriately sized pin gauge to remove any filament in the bore by lightly tapping it through with a brass hammer while blocked in a jeweler's vise or centered over a hole in a jeweler's anvil. Cotton swabs with acetone will take care of the inside of the heater block and any residue remaining on the threads of the nozzle and throat.

I've salvaged several hot ends that were completely encapsulated with plastic suing both of these methods. The pin vise is excellent for removing clogged throat bores.

CCC

Example jeweler's vise (You'll find plenty of uses for it) https://www.palmgren.com/product/13971/ ... ress-Vises

Brass face toolmakers hammer: https://www.micromark.com/Toolmakers-Mallet-2-oz-

Hexogonal jeweler's anvil: https://www.micromark.com/Hexagon-Anvil ... gLkQPD_BwE

My go-to heat gun for 30 years: https://www.techni-tool.com/product/812PR010-6966C
Male Modeler / Sub-Human

Vipao
Posts: 34
Joined: Sat Nov 21, 2020 5:58 pm

Re: Fixation of throat in hotend

Postby Vipao » Sat Apr 17, 2021 1:11 pm

ccclarke wrote:Classic upper end leak. The throat wasn't positioned against the chamfered top of the nozzle tightly enough and eventually leaks around the thread interface at the top of the heater block.

Unless it is damaged, you probably don't need to replace the hot end, just clean it up, reassemble it properly and get back to printing.
First, remove the melted plastic on the exterior with a heat gun and scraper while blocking the hot end in a jeweler's vise. The nozzle can be removed with the hot end in a vise using an open end wrench, but all of the plastic around the threads of the throat must be removed since the throat inner diameter is so thin any excessive force will break it. If the throat won't budge, don't force it. Just get the nozzle off and perform the following:

Immerse the hot end (at least overnight) in acetone to soften the plastic. Once the throat is removed, I use an appropriately sized pin gauge to remove any filament in the bore by lightly tapping it through with a brass hammer while blocked in a jeweler's vise or centered over a hole in a jeweler's anvil. Cotton swabs with acetone will take care of the inside of the heater block and any residue remaining on the threads of the nozzle and throat.

I've salvaged several hot ends that were completely encapsulated with plastic suing both of these methods. The pin vise is excellent for removing clogged throat bores.

CCC

Example jeweler's vise (You'll find plenty of uses for it) https://www.palmgren.com/product/13971/ ... ress-Vises

Brass face toolmakers hammer: https://www.micromark.com/Toolmakers-Mallet-2-oz-

Hexogonal jeweler's anvil: https://www.micromark.com/Hexagon-Anvil ... gLkQPD_BwE

My go-to heat gun for 30 years: https://www.techni-tool.com/product/812PR010-6966C


Thanks for detailed information, I will try so may I keep it as backup because I have upgraded to copperhead - slice engineering.
Problem is number of people have the same problem with this machine hotend and the different answer from Rise3D depending on Country. In some cases hotend is replaced in warranty, in other hotend is not under warranty.

Vipao
Posts: 34
Joined: Sat Nov 21, 2020 5:58 pm

Re: Fixation of throat in hotend

Postby Vipao » Mon Apr 19, 2021 9:21 pm

Any answer from Raise3d?

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Steven@Raise3D
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Re: Fixation of throat in hotend

Postby Steven@Raise3D » Tue Apr 20, 2021 12:47 am

Vipao wrote:Photos attached show leackage on top of E2 left hotend and some burns in model cooling fan. Only 4.5 mounth old machine ad 1500h of Pla printed. I shoulb be interested if someone of Raise3D staff should comment about... @Steven@Raise3D?

1618652025734.jpg

1618652025741.jpg

1618652025746.jpg


Was the nozzle on this hotend ever swapped or changed? Or is it the stock nozzle and hotend that came with the machine?

Vipao
Posts: 34
Joined: Sat Nov 21, 2020 5:58 pm

Re: Fixation of throat in hotend

Postby Vipao » Tue Apr 20, 2021 5:57 am

The nozzle was changed with a new raise3d V3 nozzle two days before installing a complete new copperhead hotend. Changed due to costant clogs and clicking from extruder without solving problems.

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Steven@Raise3D
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Re: Fixation of throat in hotend

Postby Steven@Raise3D » Fri Apr 23, 2021 12:10 am

Vipao wrote:The nozzle was changed with a new raise3d V3 nozzle two days before installing a complete new copperhead hotend. Changed due to costant clogs and clicking from extruder without solving problems.


Thank you for clarifying. If the nozzle was changed there is a chance that the new nozzle may have not been installed properly causing the hotend to leak which can lead to things like inconsistent extrusion and jams. It is really important when installing new nozzles to ensure that there is a gap left between the nozzle and the heat block when fully tightened. If there is not a gap there is a good chance that the back end of the nozzle is not fully seated against the throat tube which will cause the leak to occur.

Vipao
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Re: Fixation of throat in hotend

Postby Vipao » Fri Apr 23, 2021 4:24 am

Nozzle was changed After on reseller suggestion after clogging and clicking just appeared.

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Steven@Raise3D
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Re: Fixation of throat in hotend

Postby Steven@Raise3D » Sat Apr 24, 2021 12:18 am

Vipao wrote:Nozzle was changed After on reseller suggestion after clogging and clicking just appeared.


It's difficult to judge exactly what could have been causing the issue. It is possible that the stock hotend that you had before the nozzle swap may have also had a very small leak that got into the threads of the heat block making it very difficult for the new nozzle to be installed without leaking.

Vipao
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Re: Fixation of throat in hotend

Postby Vipao » Wed Apr 28, 2021 6:44 pm

Ok, thanks for reply. Next week probably i will install copperhead on right side. Will be interesting see default hotend, where I have never swapped nozzle..

TaterMay
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Re: Fixation of throat in hotend

Postby TaterMay » Thu May 20, 2021 6:22 pm

I had the same experience at work, though mine was so bad it damaged the heating rod and thermocouple shielding, so I went ahead and replaced them. It was by far the worst 3d printing fail I have experienced.

I came to the forum just now for another instance of this. I just noticed mine leaking once again after replacing the hot end with a brand new assembly. It's getting pretty frustrating. I made sure not to loosen this one at all before installation just to make sure I did not cause the issue. I only verified that the nozzle and throat tube were sufficiently tightened, which they seemed to be.

Regarding your concern with their vague instructions for nozzle/throat tube installation, I don't think this should be an issue. The main concern is ensuring that the throat tube and nozzle actually meet to prevent a gap, so as long as you don't bottom out the throat tube or nozzle, the gap measurement shouldn't be necessary.

Seeing others with these issues has me concerned, especially considering I am now experiencing it on a brand new, untouched nozzle.

ccclarke wrote:Just went through the same experience - only a little larger. Was greeted by a fist-sized glob of plastic encapsulating the entire left side hot end when I arrived at work on Monday morning.

Yours looks like a typical throat leak. To remove the majority of the plastic, I use a heat gun with the hot end blocked in a vise. Once the plastic softens, it's easy to remove most of it. The rest will be softened by immersing overnight in a covered glass beaker of acetone. Use cotton swabs or paper towels to wipe it off.

Remove the nozzle first - not the throat, followed by the thermocouple and heater rod. If the throat is still hard to remove, return it to the acetone bath and it should loosen up after a few hours. Do not force the throat out or you run the danger of it yielding - the inner wall of the lower section is very thin.

Once it's out, clean the upper and lower threaded portions of the heater block and bores for the thermocouple and heater rod with cotton swabs. Dry fit the components to ensure the surfaces are clean and smooth.

Follow the nozzle install procedure. I always install the nozzle first, then the throat before I tighten the nozzle so the chamfered ends mate tightly to prevent leaks. For the Pro2, I set the nozzle tip to throat end distance to a little less than 34mm, since the procedure is subjective -"Leave a small gap between the nozzle and the heater block. . . " Five mm works well. Once I started measuring the completed assembly, I haven't had a leak. You may need to experiment with the E2 to find the happy zone, but record it for posterity, or better yet, re-write the procedure using measurements instead of Raise3D's adjectives and refer to it going forward.


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