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dreamworker

PTFE coupler deformed

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Hello,

I wrote this post because in this period I use my Ultimaker 2 to create a prototype of robot and now I can't print well because my PTFE coupler is deformed. I sent 2 messages to support and 2 pm to Sander for this problem but I didn't receive answer yet. I bout my printer about one year and I use only PLA filament, and about 1,5 Kg of material until now. If Ultimaker want to consider this piece a consumable, I can't think that is acceptable time of usability for normal temperatures usage. Then I would not spend 38.75 € for a piece so fragile and I asked to have a replacement part under warranty.

Have a good day

Paolo

 

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Hi Didier,

Yes I might buy it from the shop, but I find it a tad unserious that punish first-time buyers by forcing them to buy a defective part at birth (a weakness of this kind amounts to a manufacturing defect). Especially since I should be covered under warranty, since I have not did strange experiments with my machine.

Best regards

Paolo

 

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The UM2 no longer ships with the old pure PTFE part, so first time buyers of new printers needn't worry. The glass filled PTFE part is now standard, and as Didier says can also be bought in the store for those early adopters who missed out.

Yes, it is irritating, but design defects do happen. There is an interesting discussion going on here about how to improve this part further.

Btw, do you have a picture of your PTFE coupler showing the deformation? I've used my printer a similar amount as you, and I recently replaced the PTFE coupler with the glass filled one, but in fact I found that the original pure PTFE coupler was completely undamaged. I tend to use something between 210C and 220C.

 

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The piece is deformed, presents a bottleneck in the inner part in the side that touches the nozzle, this constriction block the normal pass of the filament.

20141106 083838

 

I still do not understand why I should pay € 38.75 for a consumable, after only one year of normal usage (It cost more than a filament spool)

 

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I can't debate with you about warranty, spare parts pricing etc - that's between you and UM support.

The deformation looks quite uniform. Did you ever take the hotend apart, in particular did you remove the nozzle? I'm just wondering if the part has been squeezed vertically: pure PTFE does have a tendency to creep under load.

 

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Your PTFE still looks useful. With a 3.2mm drill you can manually check the correct diameter and correct as necessary. The lower lip reduces the overall diameter probably something that should be corrected.

My first PTFE was over, after 7.5 kilograms of PLA filament, and 9 months of usage time. The PTFE was strongly hollowed out in the lower part, this has mainly negative effects on the retraction, I think.

Anyway, I have successively been used two glass reinforced PTFE a very short time. After perhaps a hundred hours of total usage time was a lip on both parts.

Currently I use and test my first self-created ColdEnd:

Markus

 

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15€ my fault... shipping is very high for such a small component...

When i ordered mine, i asked for a spool of filament (the shipping cost didn't change), this is all due to the fact that cheaper transport services don't have insurance in case of lost shipments (and it seems it happens a lot).

 

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The new teflon is glass filled and should be less fragile.

 

In my experience even the new ones will deform under normal usage. Though judging from Dreamworker's photo I'd say his coupler is barely deformed at all. Mine end up looking far worse:

DSC00538 crop

 

Though in any case, I think a deformed teflon part is a reparable issue. And probably also the most common problem to occur with long-term usage. I was recently able to get a nearly-crippled (mostly due to problems with the teflon bit) printer back to like-new better-than-new performance by doing:

 

  1. Remove the filament from the printer.

  2. Disassemble the print-head and the entire hot-end except for the temperature sensor.

  3. Turn the nozzle upside-down and lightly sand the top surface of the threaded portion (which is now at the bottom) with some high-grit sandpaper to loosen/remove any accumulated dirt/filament. You want to have a clean, flat, smooth surface here.

  4. Clean the threaded portion of the nozzle using acetone.

  5. If necessary, remove any lingering bits of debris from the threads on the nozzle using a dissection probe/pick or similar tool.

  6. Repeat the cleaning process on the interior of the metal isolator part.

  7. Verify that both parts are properly clean by screwing the metal isolator back onto the nozzle; you should be able to easily hand-tighten the isolator until it's sitting flush against the heater block. If you can't then one part or the other is not clean yet.

  8. Drill out just the scorched bit of your teflon part. I did this using a spade bit like this one:

     

    drill_bit_spade.jpg

     

    I placed the teflon part vertically on a level surface, with the scorched part at the top, and then inserted the spade bit and gently rotated it by hand until the lip that had formed in the scorched area was gone.

     

  9. Get a bamboo cooking skewer, and bring along your sandpaper, level surface, and teflon part. Put the sandpaper down on your level surface, then stand the teflon part on it vertically, scorched side down. Insert the skewer (blunt side down) into the teflon part, and then gently press down and rotate the teflon part while holding the skewer to keep it vertical and in one place. As with step #2, your goal is to get back to having a clean, flat, smooth surface here.

     

  10. Reassemble your hot-end and print-head. Try to get the metal isolator part as tight as you possibly can (you won't get it all the way down to the heater block when the retaining screw is in place) to ensure that you'll have adequate tension to create (and more importantly, retain while printing/during retraction) good contact between the teflon part and the nozzle. Bad things happen if you allow even the slightest gap there.

     

  11. Relevel your buildplate, clean the nozzle (atomic method), load some filament, and print.

     

 

I'm not sure how much (if any) of that is officially recommended, but it worked for me. The part I was most concerned about was sanding around the nozzle, as I didn't want any dust to get inside and clog it (hence turning it upside-down to encourage the dust to fall away from the nozzle instead of into it). Doesn't seem like that caused any issues, however. And having a clean, flat surface there seems fairly important.

 

Took a bit of time to work through all of that, but still faster than waiting for a new teflon part to be shipped to me every couple of months each time one starts getting scorched/deformed.

 

I wonder if it would be viable to fabricate a comparable part out of glass/metal and then just hit it with teflon spray every once in awhile to keep the friction down?

 

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They will still deform, but it should deform much much slower.

I very much doubt if 'just' teflon spray would be enough. Especially because the friction won't be constant, as it rubs off during prints (leaving you with problems for long prints). It might work for short prints.

 

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