PTFE coupler - Theory and practical details

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Iltacitoduca
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Re: PTFE coupler - Theory and practical details

Post by Iltacitoduca »

Anders Olsson wrote:Your block appears to have little to none chamfer. The early ones had an additional chamfer where the thread starts, which some said would have a negative effect on the lifetime of the spacer, so that chamfer was removed.

Yes, both original block shipped with UM2 are without any chamfer, the change in color(more clear) is just where the thread get in contact (and I agree they will reduce lifetime of the spacer due to a reduced contact area above same conditions ... low contact area greater concentration of heat... obviously)

I think that with the TFM it works good enough for most users. The early spacers (particularly the glass filled ones) were another story, they could have extremely short lifetime with PLA under certain conditions.

This statement looks like a TV spot, I mean that it is an assertion that left me indifferent... Can you argue it better?

If you increase the area of the PTFE you will also potentially get a proportionally larger lifting force if there is a leak between the PTFE and the block.
So i am not sure that you solve the problems by increasing the diameter of the spacer.

So, we go back to my opinion that the mechanical coupling of the hot metal part and the coupler Sucks :!: !

I would personally investigate other hight temperature materials, like the Duratron spacer made by "gudo", or having an interface material between the PTFE and the block to decrease the temperature of the PTFE, like the I2K-washer from 3DSolex.
The theory behind the I2K is that by lowering the temperature of the PTFE you get down into a zone where the PTFE is much more rigid and thereby less likely to deform.
I tried both these solutions and both works fine for what I do with the printer. An additional advantage is that you can go higher than 260C for printing high temperature materials like Polycarbonate.

Yes I already have made my PBI coupler or Duratron if you like it more (is the same) (a copy of the original ones, with all the problems of the original one, except the temperature) and the intention is to make a better one with better design instead of coupling a planar face in hope it will work...
Because I suppose that the reader knows that to have a tight coupling the mating faces have to be flat and parallel, as well as with a degree of finish (roughness) such as to ensure that the fluid, which must be retained, will not pass through..
besides the fact that the coupling, must withstand the pressure forces involved in..

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Re: PTFE coupler - Theory and practical details

Post by Anders Olsson »

I can not discuss certain things as freely as I would like right now. Stepping into Ultimaker R&D-department comes with certain obligations.

In one week we can start discussing a rather nice solution to the PTFE-problem, but not before that: viewtopic.php?f=12&p=6011#p6011
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Re: PTFE coupler - Theory and practical details

Post by Iltacitoduca »

Anders Olsson wrote:I can not discuss certain things as freely as I would like right now. Stepping into Ultimaker R&D-department comes with certain obligations.

In one week we can start discussing a rather nice solution to the PTFE-problem, but not before that: viewtopic.php?f=12&p=6011#p6011

It is interesting, but... looks like a teasingly photo...
hope it will not be another scam like the "Plus" upgrade (read: Extrusion Upgrade Kit)
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Re: PTFE coupler - Theory and practical details

Post by Meduza »

Of course it is a teasingly photo, it would be weird to show everything before the official announcement... :-)

Also, please define "scam"?

As @Anders said, "I think that with the TFM it works good enough for most users.", it really is, we have had sooo much less problems with the printers after installing the Extrusion Upgrade Kit, so it feels like a whole new printer.
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Re: PTFE coupler - Theory and practical details

Post by Iltacitoduca »

Meduza wrote:Of course it is a teasingly photo, it would be weird to show everything before the official announcement... :-)

Also, please define "scam"?

why? how you will define an upgrade kit that is sold at a price that is 1/4 of the total cost of a new device, with parts that are not necessary because already present? not to mention the price / quality ratio...

As @Anders said, "I think that with the TFM it works good enough for most users.", it really is, we have had sooo much less problems with the printers after installing the Extrusion Upgrade Kit, so it feels like a whole new printer.

You have less problem not because you installed the Extrusion Update kit (EUK) but because you changed the feeder that was included in the EUK.
And what make the 95% difference was just the Feeder!
More! They sold you a new stepper motor (and the ALL print head even with rods!| LOL!!!) because they say it's more powerful! But! WTF! You already have a gear box! LOL!!! a new powerful Stepper is Totally Useless!!!
But Hey! the important is to sell something that looks nice to see! ..oh c'mon let me stop here this discussion is almost useless... if you feel happy spending money for nothing nice for you! I watch on what I invest

and oh yes! the prove that a new stepper motor for the feeder is useless, you know it very well! given that you have just realized that feeder with the pulleys, right?
I did one and tried it and I must say that it works well! obviously better of the original one since the ratio between the pulleys doubles the force of the motor!
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Re: PTFE coupler - Theory and practical details

Post by Meduza »

how you will define an upgrade kit that is sold at a price that is 1/4 of the total cost of a new device, with parts that are not necessary because already present?
The part of redundant parts would i describe as that it was designed to be user friendly to install... And the price, well you did not have to buy a new printer to get it up to the latest official specs. I do agree that i think it is a bit expensive, but people have been very happy with it.
You have less problem not because you installed the Extrusion Update kit (EUK) but because you changed the feeder that was included in the EUK.
The TFM has actually itself reduced the problems a huge amount, since so many problems were caused by worn PTFE couplers and the TFM does hold up much longer, for example, korneel has 7500h on a single coupler: viewtopic.php?f=9&t=46&start=15#p1277
More! They sold you a new stepper motor because they say it's more powerful! But! WTF! You already have a gear box! LOL!!! a new powerful Stepper is Totally Useless!!!
I'll guess that this is partly because a 200 step motor in a geared configuration does give you a better speed/torque curve, partly because that is what is used in the UM2+ and the kit is "to bring your UM2 up to UM2+ specs", wich also mean that reusing the motor would create the need for a separate firmware release with different esteps (one more thing the user can fuck up), and partly since it is shipped with the gear pre-installed on the shaft to make it easier to assemble for the end customer (not all Ultimaker users are very technical, and a kit needs to work for the majority of them), so i can see a lot of reasons for doing that?
(and the ALL print head even with rods!| LOL!!!)
Same with the print head, since you are changing the block (since UM2 does not have a Olsson Block), and both the spacer, coupler, heater cartridge and PT100 are improved ones and the fan shroud, and you would need to include the stainless coupler since it is so easy to damage, you would really only be keeping some plastic and aluminium pieces and the bearings and fans, but add at least 100% to the time it would take to install the kit.

The only thing that really puzzles me is the new axes... but i have seen users that have bent axes because of their handling of the printer so it is probably a good idea to swap them, and i have seen printers wich have never been oiled even once, so changing the bearings is not a very bad idea either...
Iltacitoduca wrote:obviously better of the original one since the ratio between the pulleys doubles the force of the motor!
Oh, and it is not that simple, a lot of the "better" part when printing PLA is actually because of the use of plastic gearing, that thermally decouples the feeder gear from the motor heat. (which was also one of the reasons that i went with a belt drive and not small metal gears for my gearbox design)

As a advanced user, i would had liked the release of a bare-bones parts kit, but i can totally see the business decisions behind the Extrusion Upgrade Kit.
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Re: PTFE coupler - Theory and practical details

Post by Anders Olsson »

Regarding the TFM, here is a short summary of it's properties from one of the suppliers: http://www.fluorotec.com/products/valve-seats/
TFM Is a modified TFE Polymer. Often referred to as second generation PTFE, TFM retains all the primary benefits of PTFE in chemical resistance etc. However TFM has a much denser polymer structure than Virgin PTFE which means it displays better stress recovery. TFM in an unfilled state has a much higher compressive strength than PTFE and lower creep. TFM retains its physical integrity at temperatures much higher than can be found with PTFE
Those improvements is precisely what was needed to solve the PTFE problems in the UM2 (higher compressive strength , lower creep, at higher temperature).
So one really should not underestimate how important the switch from PTFE to TFM was for the reliability of the UM2.
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Re: PTFE coupler - Theory and practical details

Post by Iltacitoduca »

Anders Olsson wrote:Regarding the TFM, here is a short summary of it's properties from one of the suppliers: http://www.fluorotec.com/products/valve-seats/
TFM Is a modified TFE Polymer. Often referred to as second generation PTFE, TFM retains all the primary benefits of PTFE in chemical resistance etc. However TFM has a much denser polymer structure than Virgin PTFE which means it displays better stress recovery. TFM in an unfilled state has a much higher compressive strength than PTFE and lower creep. TFM retains its physical integrity at temperatures much higher than can be found with PTFE
Those improvements is precisely what was needed to solve the PTFE problems in the UM2 (higher compressive strength , lower creep, at higher temperature).
So one really should not underestimate how important the switch from PTFE to TFM was for the reliability of the UM2.
Hi Anders,
I don't underestimate the coupler, at all... but you must also give due weight to it...
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Re: PTFE coupler - Theory and practical details

Post by Iltacitoduca »

Meduza wrote:
how you will define an upgrade kit that is sold at a price that is 1/4 of the total cost of a new device, with parts that are not necessary because already present?
The part of redundant parts would i describe as that it was designed to be user friendly to install... And the price, well you did not have to buy a new printer to get it up to the latest official specs. I do agree that i think it is a bit expensive, but people have been very happy with it.
You have less problem not because you installed the Extrusion Update kit (EUK) but because you changed the feeder that was included in the EUK.
The TFM has actually itself reduced the problems a huge amount, since so many problems were caused by worn PTFE couplers and the TFM does hold up much longer, for example, korneel has 7500h on a single coupler: viewtopic.php?f=9&t=46&start=15#p1277
More! They sold you a new stepper motor because they say it's more powerful! But! WTF! You already have a gear box! LOL!!! a new powerful Stepper is Totally Useless!!!
I'll guess that this is partly because a 200 step motor in a geared configuration does give you a better speed/torque curve, partly because that is what is used in the UM2+ and the kit is "to bring your UM2 up to UM2+ specs", wich also mean that reusing the motor would create the need for a separate firmware release with different esteps (one more thing the user can fuck up), and partly since it is shipped with the gear pre-installed on the shaft to make it easier to assemble for the end customer (not all Ultimaker users are very technical, and a kit needs to work for the majority of them), so i can see a lot of reasons for doing that?
(and the ALL print head even with rods!| LOL!!!)
Same with the print head, since you are changing the block (since UM2 does not have a Olsson Block), and both the spacer, coupler, heater cartridge and PT100 are improved ones and the fan shroud, and you would need to include the stainless coupler since it is so easy to damage, you would really only be keeping some plastic and aluminium pieces and the bearings and fans, but add at least 100% to the time it would take to install the kit.

The only thing that really puzzles me is the new axes... but i have seen users that have bent axes because of their handling of the printer so it is probably a good idea to swap them, and i have seen printers wich have never been oiled even once, so changing the bearings is not a very bad idea either...
Iltacitoduca wrote:obviously better of the original one since the ratio between the pulleys doubles the force of the motor!
Oh, and it is not that simple, a lot of the "better" part when printing PLA is actually because of the use of plastic gearing, that thermally decouples the feeder gear from the motor heat. (which was also one of the reasons that i went with a belt drive and not small metal gears for my gearbox design)

As a advanced user, i would had liked the release of a bare-bones parts kit, but i can totally see the business decisions behind the Extrusion Upgrade Kit.
I'm sorry but your arguments are weak, it seems the answer of a fan rather than a person who looks at it from a sterile point of view .. so who has a brain to read the contents, will best interpret and draw their own conclusions.
I'm not here to support or defend whatever.
And realize that the choices and prices charged are exorbitant does not take much. An example? selling at 15 euros a coupler! LOL! are you nuts? (Figuratively speaking, it is not addressed to you) A numerical control lathe take less than a minutes to make it ...
Hot end isolator of the UM2 more than 27 EURO without VAT and shipping!!!!!??? HAHA!! kidding right???

But you know all about the absurd price of spare parts... doesn't need to write it here, don't you?
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Re: PTFE coupler - Theory and practical details

Post by Neotko »

Well if people didn't charge prices for stuff they won't just sell it. Isn't like parts come from the trees and time + parts + deliver = price. You can get them cheaper on china because they don't care about warranty. You could also sell them and make all the work to distribute.

Ofc prices won't be never as buying the main parts, work is work.
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Re: PTFE coupler - Theory and practical details

Post by Iltacitoduca »

Iltacitoduca wrote:
Meduza wrote:
how you will define an upgrade kit that is sold at a price that is 1/4 of the total cost of a new device, with parts that are not necessary because already present?
The part of redundant parts would i describe as that it was designed to be user friendly to install... And the price, well you did not have to buy a new printer to get it up to the latest official specs. I do agree that i think it is a bit expensive, but people have been very happy with it.
You have less problem not because you installed the Extrusion Update kit (EUK) but because you changed the feeder that was included in the EUK.
The TFM has actually itself reduced the problems a huge amount, since so many problems were caused by worn PTFE couplers and the TFM does hold up much longer, for example, korneel has 7500h on a single coupler: viewtopic.php?f=9&t=46&start=15#p1277
More! They sold you a new stepper motor because they say it's more powerful! But! WTF! You already have a gear box! LOL!!! a new powerful Stepper is Totally Useless!!!
I'll guess that this is partly because a 200 step motor in a geared configuration does give you a better speed/torque curve, partly because that is what is used in the UM2+ and the kit is "to bring your UM2 up to UM2+ specs", wich also mean that reusing the motor would create the need for a separate firmware release with different esteps (one more thing the user can fuck up), and partly since it is shipped with the gear pre-installed on the shaft to make it easier to assemble for the end customer (not all Ultimaker users are very technical, and a kit needs to work for the majority of them), so i can see a lot of reasons for doing that?
(and the ALL print head even with rods!| LOL!!!)
Same with the print head, since you are changing the block (since UM2 does not have a Olsson Block), and both the spacer, coupler, heater cartridge and PT100 are improved ones and the fan shroud, and you would need to include the stainless coupler since it is so easy to damage, you would really only be keeping some plastic and aluminium pieces and the bearings and fans, but add at least 100% to the time it would take to install the kit.

The only thing that really puzzles me is the new axes... but i have seen users that have bent axes because of their handling of the printer so it is probably a good idea to swap them, and i have seen printers wich have never been oiled even once, so changing the bearings is not a very bad idea either...
Iltacitoduca wrote:obviously better of the original one since the ratio between the pulleys doubles the force of the motor!
Oh, and it is not that simple, a lot of the "better" part when printing PLA is actually because of the use of plastic gearing, that thermally decouples the feeder gear from the motor heat. (which was also one of the reasons that i went with a belt drive and not small metal gears for my gearbox design)

As a advanced user, i would had liked the release of a bare-bones parts kit, but i can totally see the business decisions behind the Extrusion Upgrade Kit.
I'm sorry but your arguments are weak, it seems the answer of a fan rather than a person who looks at it from a sterile point of view .. so who has a brain to read the contents, will best interpret and draw their own conclusions.
I'm not here to support or defend whatever.
And realize that the choices and prices charged are exorbitant does not take much. An example? selling at 15 euros a coupler! LOL! are you nuts? (Figuratively speaking, it is not addressed to you) A numerical control lathe take less than a minutes to make it ... and just for the crowd a rod of 3 meters of PTFE GF is right 15 Euro! you buy 15mm at the cost of 3000 mm !! LOL
Hot end isolator of the UM2 more than 27 EURO without VAT and shipping!!!!!??? HAHA!! kidding right???

But you know all about the absurd price of spare parts... doesn't need to write it here, don't you?
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Re: PTFE coupler - Theory and practical details

Post by Anders Olsson »

Pricing is interesting and difficult.
In western Europe, selling small individual spare parts like the PTFE or the isolator is really difficult from an economic point of view.

Even though those prices that seems relatively high, I am sure that is not where companies earn their profit.
If you asked them, they would probably tell you they prefer not having to sell anything that costs less than ~50 Euros, even if they get the things very cheaply.

The issue is that salaries are high, taxes are really high and sales is strictly regulated.
So besides the salary cost, each order ends up with overhead like accounting and other stuff.

That is why for example selling the Olsson block a bit more expensive with a full set of nozzles is a good deal both for the customer and for the dealer.
The dealer does not pay that much for the extra nozzles, but they add a lot of value to the customer. And all other costs like handling, accounting and shipping are not affected by a few extra nozzles.

It is really tricky stuff, particularly if customers regularly will request individual spare parts like the PTFE.
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Re: PTFE coupler - Theory and practical details

Post by LePaul »

I keep backspacing! I have much to say about the crazy taxes and fees my international customers encounter when they want to buy the parts I CNC for their R2-D2 builds. Best to stop here and see if someone starts a VAT thread elsewhere LOL :)
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Re: PTFE coupler - Theory and practical details

Post by ivan.akapulko »

LePaul wrote:I keep backspacing! I have much to say about the crazy taxes and fees my international customers encounter when they want to buy the parts I CNC for their R2-D2 builds. Best to stop here and see if someone starts a VAT thread elsewhere LOL :)
Why not to sell through the state of Delaware, or to use a shipping service was it? Afaik, companies, registrated there doesn't pay VAT. Something like this: https://qwintry.com/en
P.S. Seriously, we need another thread about VAT, or we accidentially can steel these thread :-P
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Re: PTFE coupler - Theory and practical details

Post by LePaul »

Why not to sell through the state of Delaware, or to use a shipping service was it? Afaik, companies, registrated there doesn't pay VAT. Something like this: https://qwintry.com/en
P.S. Seriously, we need another thread about VAT, or we accidentially can steel these thread :-P
In short...my buyers ask me to lie on the value of the item so they can pay less tax. I won't do that! It upsets some but sorry, I've signed my name on those forms and it could come back on me!
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