3D Printing: What are the [dis]advantages of an all-metal hotend versus one with a PTFE heat break?
Channel: Roel Van de Paar
Date: 30/06/2019

3D Printing: What are the advantages and disadvantages of an all-metal hot end compared to one with a PTFE heat break?


The Question: Related to an issue I had in 3dprinting.stackexchange.com/questions/
1205/increased-issues-with-filament-grinding, 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.

Solutions: Please watch the whole video to see all solutions, in order of how many people found them helpful

== This solution helped 6 people ==
In general, metal extruder without PTFE feeding is useful when printing with
materials that require high temperature to melt: 300oC and above. 
reprap.org/wiki/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: 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.

== This solution helped 8 people ==
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.

== This solution helped 2 people ==
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.
With thanks & praise to God, and with thanks to the many people who have made this project possible! | Content (except music & images) licensed under cc by-sa 3.0 | Music: www.bensound.com/royalty-free-music | Images: stocksnap.io/license & others | With thanks to user Sean Tapscott (askubuntu.com/users/6182), user Ryan Carlyle (askubuntu.com/users/298), user Mikhail Z (askubuntu.com/users/3839), user Mark Wood (askubuntu.com/users/14031), user JorgePerez (askubuntu.com/users/1806), user Greenonline (askubuntu.com/users/4762), user Dustin Wheeler (askubuntu.com/users/102), user Computool (askubuntu.com/users/12955), user Brad (askubuntu.com/users/12926), and the Stack Exchange Network (3dprinting.stackexchange.com/questions/2621). Trademarks are property of their respective owners. Disclaimer: All information is provided "AS IS" without warranty of any kind. You are responsible for your own actions. Please contact me if anything is amiss at Roel D.OT VandePaar A.T gmail.com.