Unclog PLA from hotend with MEK

My J head from Maker Farm was severely clogged so I read up on this forum and elsewhere that Acetone is good for ABS but not PLA. I tried using some Methylene Chloride, which is the major chemical in the Ace Hardware's brush and roller cleaner but it not soften the PLA enough.

Further reading and MEK (Methyl Ethyl Ketone) has been tested to work but the stuff is really bad for you. What isn't bad for you these days? Well, I found a can of MEK at the Home Depot and tried it. It has a very strong odor so use it outdoors!

I took the hot end completely apart, scraped some of the dried/hard PLA off and dunk all of the brass parts in a can of MEK and left it outdoors for 24 hours. That stuff really worked! All the PLA turned into a soft, goopy black stuff that I was able to scrape off easily.

Hot end is working well now, until the next clog :-).

Jose

Quote
rcjoseb
My J head from Maker Farm was severely clogged so I read up on this forum and elsewhere that Acetone is good for ABS but not PLA. I tried using some Methylene Chloride, which is the major chemical in the Ace Hardware's brush and roller cleaner but it not soften the PLA enough.

Further reading and MEK (Methyl Ethyl Ketone) has been tested to work but the stuff is really bad for you. What isn't bad for you these days? Well, I found a can of MEK at the Home Depot and tried it. It has a very strong odor so use it outdoors!

I took the hot end completely apart, scraped some of the dried/hard PLA off and dunk all of the brass parts in a can of MEK and left it outdoors for 24 hours. That stuff really worked! All the PLA turned into a soft, goopy black stuff that I was able to scrape off easily.

Hot end is working well now, until the next clog :-).

Jose

The very best and easiest way to clean a nozzle like you describe is to burn it out.
Take the nozzle off the hotend, use a piece of stiff wire to support the nozzle from the inside.
Place the nozzle in a gas flame like a cooker flame and let the nozzle get hot, but not so hot that it turns red or it may collapse.
The PLA will completely disintegrate and turn to carbon which can be washed out very easy when you cool the nozzle down.

I have had a few people bring me their nozzles that they have had blocked (not my nozzles) and I have shown them how to do this and all have worked fine immediately afterwards, took very little time to do.

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[regpye.com.au]
"Experience is the mother of all knowledge." --Leonardo da Vinci

Thanks for the tip Reg. I patiently await your nozzle which is the mail somewhere between Austrailia and Texas :-)

Jose

Quote
rcjoseb
Thanks for the tip Reg. I patiently await your nozzle which is the mail somewhere between Austrailia and Texas :-)

Jose

I hope you get it soon, it should be getting there any time now.

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[regpye.com.au]
"Experience is the mother of all knowledge." --Leonardo da Vinci

Got the hotend on Friday, thanks Reg! She's a beauty and fits inside the Jhead mount from SmartFriendz with only a little trimming around the ledge that supports the arm.

My cheap eBay PLA requires a high temp to melt, > 200c. What's the max temp that can be used with the Genie MK2? I can set them temp manually around 215 and feed PLA through it manually and it will start to extrude but I want to make sure when I do my extruder calibration that I do not set the temp to high and damage components.

Thanks,

Jose

Quote
rcjoseb
Got the hotend on Friday, thanks Reg! She's a beauty and fits inside the Jhead mount from SmartFriendz with only a little trimming around the ledge that supports the arm.

My cheap eBay PLA requires a high temp to melt, > 200c. What's the max temp that can be used with the Genie MK2? I can set them temp manually around 215 and feed PLA through it manually and it will start to extrude but I want to make sure when I do my extruder calibration that I do not set the temp to high and damage components.

Thanks,

Jose

I run all my PLA at 210C. Some brands of filament need higher, most work well at 200-210C I have found. One brand I had to push the filament trough at 217C (depends on the quality of the manufacturer)
I have printed nylon with the Genie hotend (both MK1 and MK2 are identical as far as filaments are concerned, the length of the body is the only difference) The nylon that I used required 245C, but that would be close to the temperature limit, I wouldn't go any higher than that.
Cristain on this forum has done a lot of testing of the Genie hotends and he has reported back to us that the Genie can withstand high temperatures and use many different filament types without any problems.
He has even used some exotic filaments that require a good hotend to be successful. Cristian also has a small amount of stock held in France for anyone that needs a Genie hotend quickly instead of waiting for one to come from Australia. Mano also has some stock as well if you live near to Holland, he may post his contact details here if he sees fit. Dave also has stock in USA.
Maybe Cristian can give you some additional feedback on his hotend tests?

Edited 1 time(s). Last edit at 02/22/2015 06:09PM by regpye.

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[regpye.com.au]
"Experience is the mother of all knowledge." --Leonardo da Vinci

I will try it 210C - 217C, thanks.

I was wondering if any hotend being too hot will cause a clogging issue as well. Now, this perhaps is not due to the breakdown of the PTFE inner tube or the PEEK insulator but that at those high temps, the PLA is OK only while its flowing through the hotend. When it cools down from such a high temp, it cools down somewhat differently and causes the clogs?

When a print job is done, should I extract the PLA from the hotend so that it's not sitting inside the hotend? I assume that the build up of PLA over time will be an issue unless it gets constantly re-melted with every use.

Thanks

Jose

Quote
rcjoseb
I will try it 210C - 217C, thanks.

I was wondering if any hotend being too hot will cause a clogging issue as well. Now, this perhaps is not due to the breakdown of the PTFE inner tube or the PEEK insulator but that at those high temps, the PLA is OK only while its flowing through the hotend. When it cools down from such a high temp, it cools down somewhat differently and causes the clogs?

When a print job is done, should I extract the PLA from the hotend so that it's not sitting inside the hotend? I assume that the build up of PLA over time will be an issue unless it gets constantly re-melted with every use.

Thanks

Jose

The Genie doesn't clog. What can cause problems is if your cooling fan for the printed part blows on the hotend and cools it down too much.
Watch the temperature while printing and see if the temperature will hold OK at the set levels.
Sometimes if a very strong fan is used the heater can't keep up with the temperature required and it drops down below a usable temp.
This is a good reason to add Kapton tape to the hotend, to keep the temperature stable.
Some have even wrapped a short length of ceramic tape around the nozzle to keep the heat in, but this is not needed unless you are using brute force cooling.

I have included my end code for Cura (same should work in Slic3r too)
This extracts the filament at the end of a job a short distance to stop any filament dripping. If you leave it to go cold you can just pull the filament out of the hotend without any problem.

End code:

M104 S0
M140 S0 ;heated bed heater off (if you have it)
G91 ;relative positioning
G1 E-5 F300 ;retract the filament a bit before lifting the nozzle, to release some of the pressure
G1 Z+0.5 E-10 ;move Z up a bit and retract filament even more
M117 finished... ;message on LCD screen
;G28 X5 Y5 ;move X/Y to min endstops, so the head is out of the way
G1 Y245 F2000 ;move to front
M84 ;all steppers off
G90 ;absolute positioning

I will give you the start code too, because I like to prime the nozzle before printing so that there is a good charge of fresh filament ready for use.

Start code:

;Print time: {print_time}
;Filament used: {filament_amount}m {filament_weight}g
;Filament cost: {filament_cost}
;M190 S{print_bed_temperature} ;Uncomment to add your own bed temperature line
;M109 S{print_temperature} ;Uncomment to add your own temperature line
G21 ;metric values
G90 ;absolute positioning
M107 ;start with the fan off
G92 ;zero all axis
G1 Z20.0 F{travel_speed} ;move the platform down 15mm
M117 Homing... ;Put message on LCD screen
G28 ;home all axis
M117 Levelling... ;Put message on LCD screen
G29 ;auto bed leveling probes
G92 E0 ;reset extruder
M82 ;set extruder mode
M117 Purging.... ;Put message on LCD screen
G1 Z0.5 ;move nozzle to print height
G1 E40 X90 F700 ;extrude some filament in a short line to prime the nozzle.
G92 E0 ;zero the extruded length again
G1 F{travel_speed}
M117 Printing...;Put printing message on LCD screen

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[regpye.com.au]
"Experience is the mother of all knowledge." --Leonardo da Vinci

Thanks for the info, Reg. It's really, really appreciated. I will check the temp while the fan is running during a print job. Right now, it's set to auto so it comes on after the first layer. I do have Kapton tape on it. By the way, what do you have your PLA feed rate per minute set at?

I hope all is well in Australia. I heard about the flooding in Queensland.

Jose

Edited 1 time(s). Last edit at 02/22/2015 09:33PM by rcjoseb.

Quote
rcjoseb
Thanks for the info, Reg. It's really, really appreciated. I will check the temp while the fan is running during a print job. Right now, it's set to auto so it comes on after the first layer. I do have Kapton tape on it. By the way, what do you have your PLA feed rate per minute set at?

I hope all is well in Australia. I heard about the flooding in Queensland.

Jose

No problem Jose,
If you have any problems at all with the hotend (I doubt that you will) I am always here ready to assist.
I am feeding the feed rate at 80mm/sec for most jobs and use 0.3mm layers, but ones that have detail and are a bit delicate in design I set the speed right down either by the LCD controller (go as low as 50%) or by the slicing software and use either 0.2mm or 0.1mm layers.. I also found that some designs call for reduced speeds to, these are noticeably Z scare that is caused through Cura not having random starts like Slic3r does, so to overcome the Z scaring, drop the speed down a lot on those particular parts.

I live in South Australia and flooding is the last thing that would happen in my town, we rarely get any rain, it is so dry and hot here.

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[regpye.com.au]
"Experience is the mother of all knowledge." --Leonardo da Vinci

Hi Reg. Glad to hear you are nice and dry :-)

I would like to mount a 40mm fan in front of finned heat sink and groove nut. At 210c the upper portion of the hot end is getting heat from below, I assume, and the heat is wapring the PLA mount. I am working on getting an ABS mount printed.

Can you recommend any fan mounts that would fit the Genie MK2? I have a dremel so if i need to make adjustments to the mount that's not an issue.

I do have an idea to take a thin, flat aluminum plate and placing it between the finned heat sink and the groove mount and mounting a fan to that but do not know if that would cause any issues. I would of course need to place in a slightly longer inner PTFE tube so that the pneumatic fitting can be inserted correctly.

As always, thanks for all that you do!

Jose

Quote
rcjoseb
Hi Reg. Glad to hear you are nice and dry :-)

I would like to mount a 40mm fan in front of finned heat sink and groove nut. At 210c the upper portion of the hot end is getting heat from below, I assume, and the heat is wapring the PLA mount. I am working on getting an ABS mount printed.

Can you recommend any fan mounts that would fit the Genie MK2? I have a dremel so if i need to make adjustments to the mount that's not an issue.

I do have an idea to take a thin, flat aluminum plate and placing it between the finned heat sink and the groove mount and mounting a fan to that but do not know if that would cause any issues. I would of course need to place in a slightly longer inner PTFE tube so that the pneumatic fitting can be inserted correctly.

As always, thanks for all that you do!

Jose

Hi Jose,
I use PLA for all of mine, no problems. There are so many different designs out there, it is hard to make a standard print available for use.
Yes you can make an aluminium angle bracket to go between the heatsink and the grooved nut, and the PTFE will need to be longer. The Genie design allows so many different ways of fitting, it is really up to your imagination.You should have a spare piece of PTFE that is a bit longer supplied with your hotend already. An angle bracket should be pretty easy to fit I would say.
When fitting it, make sure that the PTFE inserts into the recess of the lower brass thread properly or you may get a leak.

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[regpye.com.au]
"Experience is the mother of all knowledge." --Leonardo da Vinci

Quote
regpye

Quote
rcjoseb
Hi Reg. Glad to hear you are nice and dry :-)

I would like to mount a 40mm fan in front of finned heat sink and groove nut. At 210c the upper portion of the hot end is getting heat from below, I assume, and the heat is wapring the PLA mount. I am working on getting an ABS mount printed.

Can you recommend any fan mounts that would fit the Genie MK2? I have a dremel so if i need to make adjustments to the mount that's not an issue.

I do have an idea to take a thin, flat aluminum plate and placing it between the finned heat sink and the groove mount and mounting a fan to that but do not know if that would cause any issues. I would of course need to place in a slightly longer inner PTFE tube so that the pneumatic fitting can be inserted correctly.

As always, thanks for all that you do!

Jose

Hi Jose,
I use PLA for all of mine, no problems. There are so many different designs out there, it is hard to make a standard print available for use.
Yes you can make an aluminium angle bracket to go between the heatsink and the grooved nut, and the PTFE will need to be longer. The Genie design allows so many different ways of fitting, it is really up to your imagination.You should have a spare piece of PTFE that is a bit longer supplied with your hotend already. An angle bracket should be pretty easy to fit I would say.
When fitting it, make sure that the PTFE inserts into the recess of the lower brass thread properly or you may get a leak.

I was thinking, maybe you can use the mount I have made for the Mens Shed Special i3 machine.
It takes the hotend, has a 30mm fan, also has an attachment for a servo that you could remove if not needed. The whole thing will bolt down to a plate, so it could be adapted quiet easily.

You can find the STL at regpye.com.au/stl/i3_E3D-2bowdenx1.stl

Edited 1 time(s). Last edit at 02/24/2015 06:18PM by regpye.

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[regpye.com.au]
"Experience is the mother of all knowledge." --Leonardo da Vinci

Thanks for the advice and STL file! Will let you know what I come up with.

Hi Reg:

How is the 1mm space between the heater block and the nozzle used to seal the nozzle? I removed the nozzle to clean off some of the dried PLA it had on the side and when I hand tighten it back on, I can screw it all the way up to the heater block. Am I supposed to or just leave it 1 full turn away? Doesn't that leave a gap inside the nozzle between the screw tip and the nozzle body?

Thanks

Jose

Quote
rcjoseb
Hi Reg:

How is the 1mm space between the heater block and the nozzle used to seal the nozzle? I removed the nozzle to clean off some of the dried PLA it had on the side and when I hand tighten it back on, I can screw it all the way up to the heater block. Am I supposed to or just leave it 1 full turn away? Doesn't that leave a gap inside the nozzle between the screw tip and the nozzle body?

Thanks

Jose

Hi Jose,
The brass lower section should be set so that when the nozzle is tightened there will be a full turn (1mm) gap between the nozzle base and the heater block.
If there isn't, the brass section has been screwed in too far into the heater block.
There is a set screw to hold the brass section in place. That will have to be undone and the brass section screwed out a little to expose more of it.
The way it seals is the nozzle has a land that is machined at 118 degrees and the brass section also has a machined land to match. If the nozzle can screw up close to the heater block, the seal cannot be made properly.
To stop the brass section moving when tightening, tighten by hand while cold only finger tight. Bring the nozzle up to working temp of around 220C and then take an adjustable wrench (spanner) and fit it to the heater block to hold it still, and fit a 10mm spanner on the nozzle and tighten carefully so as not to break off the nozzle end. (don't over tighten).
The remove the nozzle, do in reverse, heat up before loosening (or the brass section can move) and after it is loose let the nozzle cool down so you can unscrew without burning your fingers.

Edited 1 time(s). Last edit at 02/25/2015 01:12AM by regpye.

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[regpye.com.au]
"Experience is the mother of all knowledge." --Leonardo da Vinci

Now I understand. Thanks.

Hi,

I use a little fan mount I designed myself.
Nothing spectacular, it just clips onto the heatsink and stays there. I 've printed it in PLA (as well as the hotend mount) and had no issues with it (thermal or otherwise).

HTH,
Yiannis.

Quote
regpye
I run all my PLA at 210C. Some brands of filament need higher, most work well at 200-210C I have found. One brand I had to push the filament trough at 217C (depends on the quality of the manufacturer)
I have printed nylon with the Genie hotend (both MK1 and MK2 are identical as far as filaments are concerned, the length of the body is the only difference) The nylon that I used required 245C, but that would be close to the temperature limit, I wouldn't go any higher than that.
Cristain on this forum has done a lot of testing of the Genie hotends and he has reported back to us that the Genie can withstand high temperatures and use many different filament types without any problems.
He has even used some exotic filaments that require a good hotend to be successful. Cristian also has a small amount of stock held in France for anyone that needs a Genie hotend quickly instead of waiting for one to come from Australia. Mano also has some stock as well if you live near to Holland, he may post his contact details here if he sees fit. Dave also has stock in USA.
Maybe Cristian can give you some additional feedback on his hotend tests?

I also tested the hotend up to 245°C and it worked fine, I didn't notice any problem or damage. But keep in mind that the temperature that you see on the screen may differ from the real temperature, because of error measurements. In my experiments I found errors sometimes higher than 10°C, so if you want to stay in the really "safe" side I would say that you should keep it not beyond 230°C. In any case, the only thing that should get damaged if you exceed this limit (and up to about 300°C) should be the PTFE liner, which is cheap and easy to replace. So if you have some spare PTFE tubing lying around, you may even print at 245°C without worries.

Besides that, in my experience this hotend is virtually uncloggable. You may find more details in the posts about the tests I made, for example here and here.

Enjoy this little jewel!

Edited 1 time(s). Last edit at 02/28/2015 03:22PM by cristian.