Two question: About CPE Printing and PTFE couplers

[morenoa0922 0]

I printed a Key Fob case in PLA, and it broke, so I am thinking on using a stronger material. Looks like CPE is the right choice, but I read that since it prints hotter, it may melt the PTFE coupler.

Do Ultimaker 2 and Ultimaker 2+ use the same coupler?

So, ... How much does CPE printing really affects the coupler?

and... Where can I buy it in the US?

Thanks

Alejandro

[IRobertI 521]

It's not the material itself, it's the temperature. Any material you print at a higher temperature will make the PTFE coupler degrade faster. How quickly is a bit unpredictable as it depends on exactly how hot you're printing, how fast your fan is cooling the PTFE and even how many retractions you're doing. The PTFE will die eventually, regardless of which material you print (including PLA), it's considered a consumable.

The UM2+ uses a different kind of material, called TFM and it also uses a spacer instead of a spring. This combination lasts quite a bit longer than the PTFE+spring combo. So I would suggest you get a TFM+spacer when you need a replacement. It's important to get the spacer instead of the spring.

You can find a reseller here:

https://ultimaker.com/en/resellers?c=US

Here are instructions on how to replace it:

http://support.3dverkstan.se/article/56-replacing-the-ptfe-coupler

[cjs 34]

Do you need to worry about couplers degrading with the Ultimaker 3 ?

The disassembly (

) of  the printcore did show a piece of teflon :/ Edited July 22, 2017 by Guest

[Dim3nsioneer 558]

Do you need to worry about couplers degrading with the Ultimaker 3 ?

The disassembly (

) of  the printcore did show a piece of teflon :/

 

No it's protected by the double heat break. Afaik it never got warmer than 100°C in the stress tests Ultimaker performed before the UM3 launch.

[geert_2 558]

I tried all sorts of keychains in PLA, PET and NGEN, just to get an idea of the durability of these materials in daily use. PLA gets harder, more brittle and breaks under too much stress. PET deforms and then also breaks. NGEN snaps also. They seem to be about equally strong in normal use.

If you want the part to last, you need to design in methods of stress relief. For example, give all parts enough room to move around freely, so they do not get stuck in weird angles and break, when you sit on it, or when you pull it out of your pocket with too much force.

I haven't tried flexible materials like nylon yet.

[gr5 2,234]

The teflon won't exactly melt. It will slowly degrade over many days. At some point it's too soft and under compression (normal use) it will squeeze the filament where it enters the hot block (at the base of the teflon). Ultimaker's newer teflon aka TFN should be fine up to 255C for long term. 3dsolex (and in usa I sell their products at thegr5store.com) makes an even higher temp teflon which they call TFN also but it's a newer, higher temp product.

I wouldn't worry about it until you start getting underextrusion. At that point you can remove the nozzle and drill out the teflon with a 3mm drill (to get you a few more days) and order a new one.

Nylon is probably your best bet. I strongly recommend Taulman bridge over other types of nylons. Nylon is quite difficult to work with but in this case (your key fob) I think Nylon is your best bet. You need to keep it VERY dry. It will get "ruined" in just a few hours or so in normal humidity air. But it's easy to dry the nylon out again.

Google about people who use a light bulb and a plastic box to keep their nylon in.

Ultimaker nylon is also excellent. That nylon can be left out for a whole day before it absorbs too much water. You know your Nylon is "bad" because you can hear the water boiling and sizzling/popping as you print and the print looks like snow (thousands of tiny bubbles).

[cjs 34]

I wouldn't worry about it until you start getting underextrusion.  At that point you can remove the nozzle and drill out the teflon with a 3mm drill (to get you a few more days) and order a new one.

Do you refer to the printcore or the ultimaker 2 coupler ?

[gr5 2,234]

I was talking about UM2. UM3 teflon shouldn't have much pressure on it (if assembled correctly) as it is sitting in a cylindrical gap that never changes. Also the ptfe in the um3 never gets above probably 100C (versus 220C typical printing temps for pla in the UM2).

[cjs 34]

Ok, thanks!

Does anyone know why Ultimaker still relies on a PTFE tube and hasn't switched to all metal ?

[gr5 2,234]

All metal sucks for pla. It's really a miserable solution if you plan to print PLA. And PLA is the most common printing material because it has such a wonderful combination of good properties.

The problem with metal is that melted PLA sticks to it incredibly well. You might be fine for a while but after too many retractions it will likely get stuck and your print will fail. Or after the printer cools down you won't be able to start up the next print as the filament is locked/bonded to the cooler portion of the hot end.