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Related to an issue I had in this question, where the PTFE tube feeding my filament to the metal tip of the extruder clogged and became discolored: what are the advantages and disadvantages of changing out my extruder (Mk10 on a FlashForge Creator X) for an all-metal solution like the one advertised here (by Micro-Swiss).

I understand that the conversion would allow me to print higher-temperature materials (like nylon), but I'm also trying to figure out the trade-offs with regard to printing PLA/ABS parts.

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  • $\begingroup$ Following. I've been having a nightmare with the throat pipe. I didn't realise the PTFE was part of it, rather I guessed it was the cause of my blockage (I'd been printing in white). I've got some all metal ones on order now. $\endgroup$ – SpaceBeers Aug 10 '16 at 11:40
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    $\begingroup$ "throat pipe" is chinglish. "Heat break" is the proper name. $\endgroup$ – Tom van der Zanden Aug 10 '16 at 15:47
  • $\begingroup$ "heat break" or "thermal barrier tube" depending on the hardware's lineage. $\endgroup$ – Ryan Carlyle Aug 11 '16 at 21:17
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This is a good question to make a comparison table. All-metal hotends Vs. PTFE liner hotends.

All metal:

  • Works well for high (+250ºC) temperatures filaments like nylon or PC.
  • No need to replace the PTFE liner (pretty obvious).
  • Retraction performs worse.
  • Plastic can get stuck to the inner walls. This can lead to clogging, more likely when changing from ABS to PLA (higher temp plastic to lower temp plastic).

PTFE liner hotend:

  • Limited working temperature. Above 250 PTFE will start to degrade.
  • PTFE tube needs to be replaced more or less often, depending on the use of your printer.
  • Retraction performs better.
  • Plastic is less likely to get stuck in inner wall (PTFE is very nonstick).
  • When using PTFE liner, the plastic is melted very close to the nozzle. Unlike other techniques, in FFF/FDM 3D printing this is more desirable. E.g. to avoid 'heat creep', for a better flow control and more accurate output dimension.

Of course there are more points to compare. Please comment to add any other useful point.

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  • $\begingroup$ Also less heat creep. $\endgroup$ – StarWind0 Aug 12 '16 at 1:24
  • $\begingroup$ what is retraction performance? $\endgroup$ – user391339 Dec 21 '17 at 2:48
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    $\begingroup$ @user391339 I know this is an old question but for anyone who comes along with a similar question, I'll take a stab at an answer (anyone plz chime in if I'm wrong): retraction is when the extruder pulls the filament back. You don't want the filament too warm when it goes back, may stick to lining, etc, which is what the heat-break helps with. Bowden configs require extra tuning / calibration and will generally have a much higher retraction speed / distance. Retraction can happen for many reasons, notably when the nozzle needs to clear a gap, so it doesn't drag filament and cause stringing. $\endgroup$ – Adam Plocher Jun 28 '18 at 13:15
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In general, metal extruder without PTFE feeding is useful when printing with materials that require high temperature to melt: 300oC and above. Polycarbonate with recommended printing temperature at up to 310oC is a good example.

PTFE melting point is around 320oC, but it may become soft at much lower temperatures, according to RepRap wiki: http://reprap.org/wiki/PTFE

From the other hand, all-metal extruder lacks advantages that PTFE ones can provide, the most important of them is the ability to have longer retracts without risk of clogging the filament tract. This is mostly important for users with Bowden-type extruders as well as for printing with soft or stringy filaments.

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    $\begingroup$ I think there is some concern about PTFE breaking down at around 250C, possibly releasing poisonous gasses. Perhaps the 300C figures are a bit misleading since the practical operating temperature of PTFE-lined hotends is much lower? $\endgroup$ – Tom van der Zanden Feb 25 '17 at 8:12
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Yeah, Yeah... Old topic I know, but still an ongoing topic for new and old hands alike.

"All metal or PTFE lined" along with "Bowden or Direct drive" Those are the questions!

This is a very unusual hobby, quite literally every possible modification, upgrade, printer setting, slicer setting, bed adhesion issue... Basically anything that can be altered at all IS SUBJECTIVE to the individual!

Forget printer brand, filament brand, model, clone, genuine etc. Just what works for one person and gives outstanding prints may not work as well or at all for someone else with an identical setup. There are just too many variables - Ambient temperatures, air pressure, humidity, geographic location, age of filament before you buy it, shipping and import method of filament, batch to batch variation of filament & the list goes on an on!

Compared with the laundry list of setup and printing problems to choose from these questions are surprisingly easy to answer!

Firstly: Bowden or Direct drive extruder.

A. Personal preference of the builder/user.

B. Suitability for your majority printing work.

I'm not starting an argument about which is better because neither one is! They both have advantages and disadvantages.

Bowden = faster overall printing speed before undesirable aberrations start to become noticeable

Direct = Slower printing speeds, but more suitable for flexible materials and easier/faster setup especially for newbies.

Personally I use a Bowden setup, mostly because I need good quality large format prints in the shortest time possible, i occasionally use flex filament but not often enough for a direct drive printer to be worthwhile investment (and with a little tweaking can still get very good results!)

Secondly: PTFE lined or all metal

This comes down to one question alone!

Do you intend printing exclusively with materials that require hotend temps above 250 °C?

If the answer is "No" do not waste your money on an all metal hotend!

Buy a couple of good quality plated brass nozzles and high quality Bowden tubing or heat break liner (and still have change for lunch and a pint or two on your way back from the shop)

Why?

Simply because getting them to work properly for lower temperature printing is nothing short of an absolute "pain in the proverbial"!

On more than one occasion I have been sucked into the hype that all metal is an "upgrade" from PTFE and quite simply it just isn't! Most of the companies that market them as an all round upgrade want only one thing your hard earned £££! So instead of marketing them as the correct hotend for high temp printing they market them as a general upgrade part. Which isn't the case!

Now if you think that you may want to try out a little ABS or nylon, even an occasional high temperature print here and there then a much better solution is to buy high quality professional PTFE liner such as the Capricorn XS series.

For normal printing below 250 °C will last 3x or longer than a standard PTFE liner and is also safe to use up to 300 °C for short periods and costs just a few £s more than your regular liner!

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    $\begingroup$ you can't print ABS or PC properly with a lined hotend due to the temperature constraints. I would phrase it "do you intend on printing exclusively under 230°C" as the lined hotend end. $\endgroup$ – Trish Dec 30 '18 at 22:36
  • $\begingroup$ Thanks Mark for such a comprehensive explanation. $\endgroup$ – m12lrpv May 17 at 0:10
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In addition to the filament printing temperature limits of PTFE-lined hot ends, and higher risk of jamming with all-metal hot ends, there is a significant potential print speed difference. PTFE is an insulator and putting an insulator between the heater and incoming filament will considerably slow the speed at which it can be melted. In very rough terms, a 1.75mm filament extruder with a 4x2mm PTFE liner can only extrude about half as fast as an otherwise-identical all-metal hot end. (On the order of 3-4 mm^3/sec PLA through the PTFE-lined hot end vs 7-10 mm^3/sec PLA through an all-metal hot end. It does depend on a lot of factors like nozzle size though.)

This is perhaps not too important for relatively slow printer styles like a Mendel/i3, but filament melting rate is the primary practical limit to print speeds in high-performance printers like Deltas or CoreXY machines.

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Just bought an all metal heat break, and I either have to upgrade my existing fan (technically possible, but currently infeasible), or reinstall a PTFE-lined heatbreak.

Printing with a Tevo Tarantula. From what I've heard, basically, for PLA and other low-temp plastics, don't use all metal heat breaks. You need a PTFE breaker in there.

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    $\begingroup$ what's the rationale behind your answer? what are you trying to communicate as the reasoning behind it? $\endgroup$ – user391339 Dec 21 '17 at 2:47
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Something not being considered here is where the PTFE liner terminates relative to the tip.

On the latest V6 J-head that I recently purchased on ebay, it only runs to the top of the M6 Stainless heat-break, about 25mm away from the tip. I use this on my Mendel Max, with both PLA, and ABS. No real problems, running at about 70mm/s, but I have had heat-creep jamming problems when the nozzle became blocked, which I put down to cheap grade filament.

On the Wanhao i3 mini, that I recently dismantled, with a similar looking hot-end, the PTFE liner runs all the way to the brass tip. This particular printer only works with PLA. I am yet to put it through its paces, to discover the benefits/negatives of this difference.

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Nowadays you don’t need all metal hot ends if using Capricorn PTFE tubing rates at 340 °C. Works great, runs smoothly, problem free and prints nylon without a glitch.

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My Tevo Tarantula had an all metal hotend included and I never ran into any issues only printing PLA and PETG, most of the time I was even able to pull out the filament while the printer was cold.

After I upgraded to an E3Dv6 clone with PTFE lined heatbreak I started to have issues because of the filament getting stuck where the Bowden tube and the heatbreak connected, so I recently replaced it with an all metal heatbreak again and the issues instantly went away.

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