Hot end tip shape: which is better?

[ru.aliexpress.com]
[ru.aliexpress.com]

Тhe two above (just example) have different tip shapes - one is pointy, which means less plastic sticking to it, one is flat, which means it will press against plastic, creating more aghesion.
Which one is better?

The first nozzle is a better design. The second nozzle with the broad tip will cause issues, it will lift and drag percentage infill, as the flat drags across previously printed material.

I desagree. You want a flat noze to squeeze the filament on the previous layer. I prefer the E3D style nozzle for the flat end, and also because the nut is larger, so you have more surface and more torque when you want to unmount it. The nut stays in better shape too.

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Collective intelligence emerges when a group of people work together effectively. Prusa i3 Folger (A lot of the parts are wrong, boring !)

Hm... Now I am exactly where I was when asked this question...

I'll stick with my several years of experience, from making my own, and working with manufactured nozzles. I get the best print and surface quality with a tip that is approximately 3 times wide as the nozzle diameter, i.e. a .75mm tip, for a .25mm nozzle.

This way you are only passing over the width of a single extruder pass with the following pass, not dragging across several previous extruder passes.

You want a flat tip like the one used in the latest version of original J-Head and e3d hotends. The simple reason being that when you have a long nozzle you'll have unacceptable difference of temperature as compared to the one measured by your thermistor. That's also one of the reasons why latest version of e3d hotend and original J-Head (not the Chinese crap) has moved the hole for the thermistor closer to the tip of the nozzle.
I believe people who create specifications for original J-Heads have much more experience than some random guy on the forums, if you agree, check out how the J-Head evolved over the years here.

PS: if you want to buy a hotend from aliexpress, I would recommend either getting e3d v5 or e3d v6 from Naruto store - even the prices are a bit higher they are worth it. Also, remember to attach a fan to your e3d hotend before using it.

Edited 3 time(s). Last edit at 04/02/2015 09:10AM by hakimio.

Second one is better.