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lifetime of your PTFE coupler (Poll)

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Dear community

One question: what is the lifetime of your PTFE coupler, particularly the newer glass reinforced version, in terms of printing hours?

I installed a new PTFE coupler at h=405 (printing hours), I am now around 600h and have the strong feeling the PTFE couple issue is back. I judge this at some misprints (under-extrusion), as well as the small lateral bump in Atomic-method pull-outs in the vicinity of the hot end of the coupler.

Is 200h a reasonable lifetime for the coupler? If this is the case, then one can consider the coupler as a consumable, and Ultimaker should re-think its price. Machining cost for such parts in batches is well below Eur 3, as many of us (at least in the engineering field) know.

Regards,

Ioan.

Edited by Guest

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PTFE lifetime all depends on the printing temperature!

260 (abs printing) shortens it significantly.

PTFE starts to decompose slowly at 200C, hyperbolically so around 230.

PTFE is fantastic in the way that it is cheap and very slippery!

I tried several chinese variants from ali, but they all are the wrong material and/or wrong dimension.  It needs to be very finely machined!

There is no standard for PTFE, so many variants are possible.

Dupont is an industry standard. It is not what you get in alibaba for 5$ / pcs.

The ones from UM are very good!

Edited by Guest

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Yes, they are "good", but 200h of print as lifetime (if that ends up being confirmed, I just re-launched the print) makes them a consumable. One can't ask for Eur 10-15 per unit in this case, considering that they don't cost more than Eur 3 to produce (way less actually, and even Swiss made). I'm going to ask a (Swiss) manufacturer for a quote, for 1000 parts. We'll see.

Technically:

It is a design fault (or too quick a compromise) to subject a PTFE-matrix component to a load, and 200°C, while stating that the ideal extrusion temp is around 210°C. The glass temp. of PTFE is in the 140° area; works on the subject (strong softening >140°C) abound (1).

Reinforced or not will only delay the issue, never solve it.

In other words, the hot end should be re-engineered to allow for a strong temperature gradient; metal part homogeneously at >200°C, coupler <<140°C. This can be done with proper heating and cooling circuit.

(1) Example: http://www.ewp.rpi.edu/hartford/~peetrm/Other/ME%20Project%20References/The%20properties%20of%20poly%28tetrafluoroethylene%29%20%28PTFE%29%20in%20compression.pdf

 

PTFE lifetime all depends on the printing temperature!

260 (abs printing) shortens it significantly.

PTFE starts to decompose slowly at 200C, hyperbolically so around 230.

PTFE is fantastic in the way that it is cheap and very slippery!

I tried several chinese variants from ali, but they all are the wrong material and/or wrong dimension.  It needs to be very finely machined!

There is no standard for PTFE, so many variants are possible.

Dupont is an industry standard. It is not what you get in alibaba for 5$ / pcs.

The ones from UM are very good!

Edited by Guest

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Yes! Glass fill does not increase temperature tolerance.. but the collapse happens more abruptly...

Liquid PLA sticks to just about everything!

I have tried other material which is so slippery that an ant, Ameise, can not climb it, which can take 290C continuously, which is "self lubricating", and PLA sticks to it.

High quality Teflon just works. And yes, it is a consumable..

Scenario:

Cooling circuit to cool the retraction area, more heating to heat the hot end (because it looses power to the cooling), more cooling to the hot end support structures, cool the back end of the cooling circuit (which gets hot) etc...

--I am just not sure...Maybe a litte like building a Patek Complicated so you can know where the Moon is always, but you can check that in the internet using your phone also...

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Thanks.

Anyone any idea how much glass in % in the "new" couplers?

25%?

I.

 

I had one of the older UM2 non-glass filled ones and it lasted me roughly 500 print hours. It develops a little lip that messes up atomic pulls & under extrudes. I've put in a new glass filled one recently and it's been working great.

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Well...this time the print ceased after t=3h (out of 14) and in the morning, the nozzle was all black, burnt PLA. The feeder had logically ground the filament. Upon disassembly, the coupler is not that deformed...something else has caused the nozzle to clog, and the filament to get burnt. It was kind of gradual, as the (white) part has slightly tan last layers.

I changed the whole (with typically ~1h of work...) as I had a spare hot end kit , but would like to recover the nozzle.

Any idea of a solvent which can remove the burnt PLA? Or should I burn it with a gas flame?

Difficult to imagine that the nozzle is a consumable too!!!!

Frankly, it's a nice machine, but Ultimaker actually sells a kit to fiddle with. It is not a mature product, and as buyers of this generation we're actually working on improving a beta version. Interesting for me, but not sure everyone is in this state of mind.

Edited by Guest
typos

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At times it seems like a finicky machine and then you get in the groove and print 100 parts in a row with no fiddling necessary.

I would burn it out with hot flame but don't melt the brass. There is a huge safety margin between carbonizing the pla and melting the brass but you can't just leave it in the flame thoughtlessly. Keep a low duty cycle (in the flame less than half the time) and when it seems hot enough that all the pla is burnt don't heat it any hotter than necessary.

I've done this myself and was probably more careful than I needed to be.

I would follow that by holding the block with pliers and doing many rapid "cold pulls" ouside of the printer with a short length of PLA or even better using nylon filament to get all the gunk out. Or you could try q-tips or toothpicks and water and soap. Having a steel hypodermic or guitar string or acupuncture needle helps greatly.

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One input to the last contribution.

It is definitely NOT to the customer to "get in the groove".

Noone here would tolerate a "get in the groove" use of any of the devices one has purchased for private use. Play a DVD, even 100 of them...once one gets in the groove? I guess it would be difficult to market.

Ultimaker sells an immature product. It is OK for me, but it should be marketed as such.

It is immature, but not far from being mature. Re-think the coupler, the feeding device, and the filament spool holder, and it will be fine.

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Sorry but heating plastic at a constant speed, cooling, moving, pushing. It could be better ofc, but there's no press and wait 3d printer. This machines ain't laser printers and even that ones can get the paper stuck. It's a mix of robotics and heat extrusion where the kind of plastic changes the job radically. This are mecanical extrusion home printers and as any other moving parts machine it needs care, replacement parts, etc. Also every plastic works different and needs different cares so unless you block the users from using any plastic available and focus on just one, then the fiddling it's inevitable.

I used a good 3 months before buying my first 3d machine just to know that I wasn't buying a dvd. I was buying a complex and mostly manual automatic plastic extrusion.

Ofc there are frustrating moments but this it's a rather new technology and at this prices the amount of automation it's limited.

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I am perfectly aware of all that.

Fact is that a few simple improvements are obvious to me (materials/mechanical engineer) to make the Ultimaker more user-proof. For instance, subjecting a PTFE part to a load, at a temperature in excess of is Tg is a mistake, to quote 1 out of 3, and there are ways around this.

Edited by Guest

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As far as I know there is no printer on the market that is more reliable. I talk to lots of people with lots of other printers and the UM *seems* to be the easiest to get working smoothly (at least printers that cost < $10,000). But I agree it could be much better. Lots of people have lots of problems. Not me.

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PTFE lifetime all depends on the printing temperature!

260 (abs printing) shortens it significantly.

PTFE starts to decompose slowly at 200C, hyperbolically so around 230.

PTFE is fantastic in the way that it is cheap and very slippery!

I tried several chinese variants from ali, but they all are the wrong material and/or wrong dimension.  It needs to be very finely machined!

There is no standard for PTFE, so many variants are possible.

Dupont is an industry standard. It is not what you get in alibaba for 5$ / pcs.

The ones from UM are very good!

 

"So PTFE starts to decompose slowly at 200C, hyperbolically so around 230...."

Since most, if not all, of the filament materials that we as 3D printer owners have melting temperatures around 200C or greater, WHY was this particular material (PTFE) chosen as the choice for this coupler?

It seems to me that this was chosen so that we would keep purchasing these dumb little components over time. Surely there is a material that would be much more durable to the printing temperatures that we use than this. No WONDER I see a bunch of melted brown gunk when my UM2e starts to clog: the PTFE coupler has begun to burn and flake off, going inside of my printer nozzle and messing up my whole operation. I use this printer a lot, but now I am starting to regret getting this company's product. Great job, UM, and also, nice work on making this nozzle NOT easily replaceable (need to open up the entire extruder end effector). You guys are heros. Please fix these problems in all your future models.

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