Does everyone end up with the PTFE tube problem?  

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Bodgers
(@bodgers)
Active Member

I've changed the PTFE tube in mine now after support suggested I inspect it and potentially change it. The one in the printer was noticeably smaller in both dimensions. 

It is now improved. Not perfect - I have to slow things down a lot for the first layer for successful prints, particularly if there are small details like circles. About 50% speed on standard PLA profiles.

Not exactly the "it just works" setup I thought I was buying into, but it works for now.

Only issue now is that I'll have to replace the tube after every 50 hours of printing. With Prusa no longer shipping to the UK that's going to be a problem.

 

Posted : 21/01/2021 6:09 pm
karl-herbert
(@karl-herbert)
Illustrious Member
Posted by: @raymate

Have Mini+ on order its not shipping to just before March, the more I read about the printer the more I thinking of canceling my order. Because of this PTFE problem many seem to have.

The Prusa MK3 is out of my price range but the mini is still not a cheap investment for me as its coming to Canada along with imports and shipping im getting well over $ 700 CND also being so far away if I need more parts to fix the tube issue its a long wait time and costly to get them out to Canada

Do all the printers suffer from this issue?

Cant some other material be used to fix this issue?

I waited for the Mini+ in thinking most of the earlier issues would be ironed out by now.

Because they are so behind on orders Im thinking they are just rushing them out without assembling them properly, few users have reported new machine failing within a few days of printing and found screws needs to be tightened or hot end not in correct position.

I don't want to cancel it and I cant afford the MK3.

But this is a forum normally used for issues so I just hope many units are working fine and never needs tinkering with.

Have Prusa ever acknowledged an issue with this tube setup.

Prusa also offers a DIY kit for self assemble. With this you can exclude assembly errors as far as possible and have control over the result.

https://shop.prusa3d.com/en/3d-printers/1387-original-prusa-mini-kit.html#

Statt zu klagen, dass wir nicht alles haben, was wir wollen, sollten wir lieber dankbar sein, dass wir nicht alles bekommen, was wir verdienen....
Posted : 21/01/2021 7:37 pm
bobstro
(@bobstro)
Illustrious Member
Posted by: @bodgers

[...] I have to slow things down a lot for the first layer for successful prints, particularly if there are small details like circles. About 50% speed on standard PLA profiles.

How fast were you previously printing your first layer? I always slow print speeds down to 25-30mm/s for the 1st layer, well below 50% of normal speeds. If the first layer doesn't adhere, there's little point in continuing the print, so I'm OK with it taking a few extra minutes to complete.

My notes and disclaimers on 3D printing and miscellaneous other tech projects
He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan...
Posted : 21/01/2021 9:09 pm
Bodgers
(@bodgers)
Active Member

@bobstro

The default PRUSA PLA profile is 30mm/s, so I'm leaving it as that and dialing it down to 50% manually at the printer. So that's 15mm/s.

Previosuly i could leave it as 30mm/s just fine.

Posted : 21/01/2021 9:36 pm
bobstro
(@bobstro)
Illustrious Member
Posted by: @bodgers

The default PRUSA PLA profile is 30mm/s, so I'm leaving it as that and dialing it down to 50% manually at the printer. So that's 15mm/s.

Previosuly i could leave it as 30mm/s just fine.

Ah, gotcha. I wasn't sure what the 50% related to. Is your problem that the prints come loose at higher first layer speeds? Typically, this is due to adhesion, with Live-Z calibration and bed cleaning the root cause. I don't want to firehose you with information you already have, but if that is the problem, it is common to have it start up after some time as either the bed is fouled or the printer drifts out of adjustment with use. The fix is straightforward. The printer is most "just works", but there is some maintenance and upkeep required.

 

My notes and disclaimers on 3D printing and miscellaneous other tech projects
He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan...
Posted : 21/01/2021 10:55 pm
Crawlerin
(@crawlerin)
Prominent Member
Posted by: @cwbullet

@raymate

Don't let it discourage you.  

Not only that ... now that OP knows there is potential of this issue occuring, it will be much easier to diagnose and fix it. Hopefully more permanently.

Posted : 22/01/2021 1:30 am
CraigB
(@craigb)
Eminent Member

This might be a question for Prusa when my printer actually arrives at the top of March given that they may make adjustments between now and then.  But based on this thread and others I've read. Would it just be prudent to replace the PTFE tube with the extra provides at the start vs "risking" having an issue with the tube that comes pre-installed?

Posted : 23/01/2021 7:28 pm
mark
 mark
(@mark-7)
Estimable Member

@craigb

Since many, including myself, have had no issue with the PTFE tube, it seems prudent to wait until you have an issue as described and then replace the PTFE tube if it appears to be a problem. It is exactly the same as the one it shipped with. If you use it, then you have no spare. Just start using the printer. It is likely you will have no issues. If you have issues, search for them on these fine forums. Don't worry about issues that have not happened yet just because some have posted about them on the forums. Don't follow "fix it till it's broke".

Regards,

Mark

Posted : 23/01/2021 7:48 pm
CraigB liked
Bodgers
(@bodgers)
Active Member
Posted by: @bobstro
Posted by: @bodgers

The default PRUSA PLA profile is 30mm/s, so I'm leaving it as that and dialing it down to 50% manually at the printer. So that's 15mm/s.

Previosuly i could leave it as 30mm/s just fine.

Ah, gotcha. I wasn't sure what the 50% related to. Is your problem that the prints come loose at higher first layer speeds? Typically, this is due to adhesion, with Live-Z calibration and bed cleaning the root cause. I don't want to firehose you with information you already have, but if that is the problem, it is common to have it start up after some time as either the bed is fouled or the printer drifts out of adjustment with use. The fix is straightforward. The printer is most "just works", but there is some maintenance and upkeep required.

 

It's not a bed cleaning issue. I clean the bed with IPA each time, it is super clean. 

Lost count of the amount of times I've done the initial layer calibration, it's nuts.

The fix isn't straightforward as I actually don't think it's completely cured. The tube replacement basically makes it usable, but it's not like it was out of the box.

Ultimately, I think the hot end design needs a revisit. A Bowden setup isn't going to be as good as direct, but it can be better than this.

Knowing what I know now, Ok think I'd just buy an i3 clone and fiddle with that.

 

 

Posted : 23/01/2021 8:06 pm
raymate
(@raymate)
Estimable Member

@mark-7

I like your advice the best.... wait to I try it, then see how it goes.

It's got to better than the Monoprice Mini that Ive hammered for 13 months none stop.

----------------------------------------------------------------------------------------------------------------------------
Prusa Mini+ (Ordered Dec 19,2020 - Arrived Feb 21,2021) stated clicking Mar 2nd / MP Select Mini V2...
Posted : 23/01/2021 10:40 pm
CraigB liked
cwbullet
(@cwbullet)
Illustrious Member

@bodgers

You will figure it out with the help of the forum or chat support.  Juts give us time to figure it out.  

--------------------
Chuck H
3D Printer Review Blog...
Posted : 24/01/2021 1:12 am
Slamer
(@slamer)
New Member

Ok. I think I'm one of the Ptfe tube issue people. I'm having serious clogging issues. I've cold pulled, acupuncture needle cleaned, raised hot end (and adjust pinda), purged at higher temps, and still can't get the pla to push through. 

Initial set up and first layer calibration went great so did the logo print, two benchy prints and one test print of my own. Then the next day I was getting the clogging issues

For those of you who have replaced the tube was it visual damaged? When I took the tube out to raised the hot end I did not notice any damage... wasn't specifically looking for it either.

Just wondering what to look for if I try replacing it.

Posted : 24/01/2021 2:44 am
Pinkie Pie
(@pinkie-pie)
Eminent Member

@slamer

Dont replace it - put a additional 1-3mm cut PTFE over it (inside that brass thing) . It will insure that ptfe has correct length and compression

Posted : 24/01/2021 11:23 pm
LeeM
 LeeM
(@leem)
Eminent Member

@slamer

Mine wasn't damaged as such, it was shorter than it should be (shrunk maybe ?) which caused issues.

Posted : 27/01/2021 2:55 pm
LeeM
 LeeM
(@leem)
Eminent Member

@slamer

Did you check the length when you removed it ?
It should be 43.4 +-0.1mm (see pic. at step 9 here https://help.prusa3d.com/en/guide/how-to-replace-a-hotend-ptfe-tube-mini_119449 )

Posted : 27/01/2021 3:03 pm
Bodgers
(@bodgers)
Active Member

Yes mine was also shrunk in height and width.

 

I actually think this hot end shouldn't be run at anything above 260C. I'm convinced mine did it have taking it to 275 whilst doing a cold pull procedure a couple of times.

They should have an all metal version and limit this to 260.

 

Posted : 27/01/2021 4:02 pm
cwbullet
(@cwbullet)
Illustrious Member

@bodgers

Talk about heat creep.  The all metal version might be a problem at high temperatures.  

--------------------
Chuck H
3D Printer Review Blog...
Posted : 27/01/2021 5:36 pm
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