Sorry for deleting the post that mentioned a brand. Wait for results pls.
That would be a constriction test. It is done by dropping a ball bearing through. To pass typically the ball must travel at 1 inch per second or greater average speed.
I should add, it’s usually me that makes the social mistakes so no judgements just a heads up. hope I didn’t sound mean, if so my apologies.
So what’s the purpose with the tube in printing? Is this only for non-direct drive 3d filament printers?
Can use those tubes for pulling filament through too, to reduce snags or otherwise guide the material. I use them for direct drives to provide a smooth path from gear to heat break, but that’s only like 40mm or so.
That doesnt matter, because I used the same „curly“ Filament and the tubes are looped the same during the friction test.
Anyways, I want to mention, that friction in terms of „lower friction than regular PTFE“ is a thing that brings a very low additional value for printing. This is nearly unimportant. WAY MORE IMPORTANT are things like stretchability or general quality. And by optical inspection, the green and blue ones are bad ones.
Do some heat tests… Melting point, glass transition temperature, smoking temperature, not in yet order.
I see some destruction up ahead,
naaa, I am not going to heat/burn them. This is a pointless thing to do.
I would suggest outgas tests, if possible. I realized frequently that my filament gets brittle when I leave it in the tube for a few days.
I thought it would be good to understand how they would perform for a Hotend liner…
Make Torture test - Fine positive features.
Use a retraction distance that is marginal, but identical for all tubes, so that some amount of ooze/string/angel hair is present for all prints.
Compare amount of stringing etc between the tubes.
In my mind this is the most “representative” performance test that we can do. Measuring friction, ID, concentricity, etc are all just presumed proxies for extrusion performance and flow control authority, which is what a “better tube” is trying to solve.
Overall our objective is better prints, so insofar as is possible we should try and measure the quality of the prints rather than measuring proxies and assuming downstream effects.
@Rene_Jurack Lower friction isn’t super important for hard filaments, but seems crucial for printing flexible filaments in a bowden system.
I did print 18 parts with the same settings. Constant speed (80mm/s), constant temperature (230°C), constant cooling (80% on). 0.3 micro swiss nozzle, blue extrudrPETG. The only thing changing: the retract length from 0.0mm to 4mm in 0.5mm intervals.
Subject one is the white PTFE tube that E3D-online used to sell since some time. Subject two is the new hyped Capricorn tube. Both tubes had EXACTLY the same length and were mounted with an anti-backlash clip so that they don’t move back and forth.
In my opinion, the best result was:
- white PTFE: 1.5mm retract
- capricorn: 2.0mm retract
For anyone who wants to take a look for himself, here are the detailed pictures: http://well-engineered.net/dump/prints.zip
And I did a stretch-test because a less stretching Bowden tube is a better working bowden tube. The white bowden sold by E3D-online is doing better than the capricorn.
Interesting results @Rene_Jurack !
Our tests were with 0.40mm nozzle, PLA @215C.
Our main extrusion responsiveness criteria is printing tracks onto a very level bed and observing “bulge” on extrusion start and “tail” at end of extrusion. Less bulge and tail = better.
The other qualitative check is just trying to push filament into the tube while one end is blocked off. The captube we did this with had a much higher apparent spring-k, presumably due to tighter internal ID.
I realise in writing this that what I am presenting above effectively constitutes two qualitative anecdotes, and the plural of ‘anecdote’ is not data.
Your tests make me want to go back and test more rigorously.
One thing I do know, from having QC’d thousands of km of PTFE tube is that making it can be difficult and sometimes inconsistent. The paste extrusion process is inherently less consistent than the thermoplastic extrusion process used to make things like filament and nylon tube. Furthermore the captube in your images seems off, out of round, perhaps there’s QC issue there. We only QC our own E3D tube, and have taken it on good faith that the captube we stock is in spec.
It’s midnight on a Saturday, and I’m out of office for a week, but I’ll endeavor to have this looked at in more depth at E3D and see what the captube guys think on the matter too.
@Michael_Hackney - you probably know Bowden tube tuning better than anyone I can think of, and you’re a third party. If you’re willing can I get you some captube to test and give feedback on?
@Sanjay_Mortimer1 Absolutely, I’d love to try it out.
@Michael_Hackney - to be clear we’re talking about Capricorn XS tube here, which is very dark blue, near black as per your blog I think you might even already have some of the stuff?
I do have 2m or so. Just got it a couple of weeks ago but haven’t tested it yet. I can move that up to the front of the list.