What qualifies a hot end a "good" hot end?

My first printer I bought a kit of a popular design. Parts didn't seem too bad though I do not like the printer design. Anyway It came with a Hexagon Hotend. I've been at this nearly a year and it hasn't given me any trouble at all. I'm working on building a better printer and picked up a second hexagon because of the reliability of my other one, however, I see them almost never mentioned so I'm curious. Is there other parameters that I'm unaware of that would make it a good or poor design?

Most cheap hotends are poorly designed and have gaps between the separate parts (or no cooling) that can let the filament pool in them if not cooled properly. Quality pieces have no gaps or use properly machined parts that eliminate or minimize said gaps. I use a Prometheus V2 and am very pleased with it's performance. There are a few others that will be mentioned here soon. A quick web search and some reading will reveal all grasshopper.

Hi guys,

I desagree. Actualy you can get excellent E3D chines copies for less than $10.
They have no gaps and, as a genuine E3D V6 owner, I can't see any difference.
The Hexagon is a good hotend, if you like it, stick to it.

What makes a good hotend is :
- a heatblock that melts the filament quickly
- a heatbreak that prevents heat to raise on the coldend part
- a proper heatsink that allows to keep the coldend cold
- a precisely machined filament path to help the filament flow
- price and avalability of spare parts, especialy nozzle diameters

++JM

The chinese copies can be functional but you may need to make modifications in some circumstances. It has been my experience that the fit and finish is rougher for the chinese copies. In particular the polish of the inner surface of the heat break tube. This can make a big difference for PLA and cause jamming issues unless the path is very well polished. If it's a model with a PTFE sleeve then this issue is eliminated. Also the nozzle threads and mating surface seemed rougher. This may or may not cause leakage depending on the severity of the roughness. Polishing your own heat break tube would likely require purchase of equipment since most people don't have polishing compound, etc. at home.

It's a matter of preference. Overall you will likely spend more time (averaged over many customers) getting chinese copies to work reliably than you will with originals. Also waranty service is likely much better for the originals. It's often a trade off between time and money. On the other hand you might luck out and save both.

On the subject of what makes a good hot end, I would add low friction filament path, the ability to heat to high enough temps for all filaments you are planning to use, enough heater power to keep the nozzle at temp during your fastest extrusion, ooze control. I don't know if we have good measures of many of these qualities other than anecdotally.
It seems that moving from J-Head to E3d many saw an increase in friction of the filament path due to the all metal heat break evan though the heat break is well polished. With the reintroduction of a PTFE liner for many of the E3d hot ends that may have gone away. The primary benefit of all metal hot ends is the higher available temps. J-Heads will melt at a little above the high range of ABS extrusion temperatures.

Heat flow depends on heat block size and composition.

Ooze probably depends on many things, but mostly temperature and melt zone size.

Reliability is another. On the one hand J-head style hot ends are mostly used fanless so fan failure is eliminated as a source of print failure, all metal designs require active cooling so fan failure generally results in a failed print.

Edited 1 time(s). Last edit at 11/12/2015 02:00PM by bryanandaimee.

I've gotten about 5 Chinese style metal hotends. All with the PTFE liner. All print well. A couple weren't machined properly in the top half. the filament would coil under the Push to fit fitting instead of being guided into the nozzle. I printed out a guide that goes between the hotend and the Push to Fit to stop this. After that it works properly.

That being said, I will probably buy the E3DLite next time since it's priced well.



Edited 3 time(s). Last edit at 11/12/2015 02:19PM by madmike8.

One of the things that makes a hot-end good is a design that anticipates disassembly and reassembly. That means there are flat surfaces to allow you to grip the pieces that screw into each other with tools. There should be no wood parts, and plastic should be limited to teflon lining of the cold end of the tube. The heater must be mechanically coupled to the heat block with as large a contact area as possible. The thermistor should be anchored securely in the heat block. It's nice if it uses a "standard" mounting, if there is such a thing.

I have a Budaschnozzle which is a perfect example of awful hot-end design. There's a threaded aluminum tube going into the heater block and no way to grip the tube without destroying its threads. Beyond the assembly/disassembly issues, it has wood parts that dry out and become brittle and break easily. Heat is provided by a resistor that fits loosely into its hole- a lousy way to couple heat into the block. It has heatsink fins on a piece of teflon tubing- absolutely ridiculous! It's as if it were designed purely for looks without regard to function, or designed by someone with zero understanding of how a hot-end works or what it's supposed to do.

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Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

Hi guys,
I agree, the Budaschnozzle is a nightmare.
The worst thing ever is the cheap all in one chinese stuff,
with a big block over the heatbreak, fixed between the extruder motor and a heatsink.
So, there's no proper cold end, and the motors acts as a part of the heatsink ! Rubbish !

Quote
bryanandaimee
The chinese copies can be functional but you may need to make modifications in some circumstances. It has been my experience that the fit and finish is rougher for the chinese copies. In particular the polish of the inner surface of the heat break tube. This can make a big difference for PLA and cause jamming issues unless the path is very well polished.

Sorry I still desagree. I own 8 both genuine E3D hotends and chinese copies :
V5, V6, Lite6, and I'm waiting for a Cyclops and a Chimera legend pack.
Some are full metal, some are with PTFE tubing. I print mostly with PLA with no issue.
As I said earlier even full metal chinese copies are as shiny as genuine versions, parts can fit any of them.
Actualy, I can't remember which ones are genuine or not, and cannot identify who are who.
Anything is pretty the same in fit, finish, screws, whatever it's inside or outside.

I kwow there's approximative copies, but you can easily identify them
(shine, phillips screws, spot blasted heatblocks, rouded corners heatblock...).
But actualy most of the production are good copies made to the specs, at reasonable price.
I know several skilled reprappers who tested and agreed.

++JM

Edited 2 time(s). Last edit at 11/13/2015 06:38AM by J-Max.