hot-end mechanical improvement idea..

I have an e3d v6 but what I observe is a similar situation with other designs.
Why can't the heat-break and the heater-block both use clamping-block designs like the heater cartridge so that removing either is not a major chore during freeze-ups, filament changes, etc. In my case I have to unplug the heater-block wires then try to spin it around the heat-break threads with the cables trying to hit all the things dangling off of the effector platform like fans or z-probe devices. Bending the wires down to clear then causes excessive bending of the cables near to block and eventually breakage.
With good dimensions I don't see why heat transfer would be much diminished. Maybe I'm wrong and this was wrestled with ages ago. It would also be so much cheaper to build!
(of course the nozzle threads have to be accommodated somehow but that is what 'creativiity' is for )

Its sooo... much easier to do average fit threads than a slip fit. It doesn't need to be 'ground' as E3D has stated they do on cyclops & kraken. just needs a smooth finish on a controlled surface(both faces, the ID of the hole, and the OD of the heat break). Which might cost slightly more to do... if at all. But from where I'm at I would prefer it, but market wide...

The biggest problem with the design that I see is that gorillas(anyone that doesn't know that it doesnt need to be that tight) will often over-tighten the grub screw/set screw and deform that surface making it impractical to do since it likely would be trouble to get out, need re-work after you get it out, or be unuseable/ineffecient after the first shot.

Meanwhile sloppy threads can be run in and out and are a lot more forgiving in that regard. even if they are over tightend/deformed a bit they are useable as long as the threads hold.

The nozzle and the heat brake need a tight contact to prevent filament getting pushed in the thread area.
Hard to implement this in a foolproof way with only a clamping screw.

Maybe one day we´ll see thermal barriers with clockwise and counterclockwise threads for the heaterblock and the heatsink.
That way, you could unscrew the assembly by only turning the thermal barrier.
-Olaf

Edited 1 time(s). Last edit at 07/15/2015 03:23AM by o_lampe.

Just having a pair of flats or a hex machined onto the heatbreak in the space between heatsink and heater block would make it much easier to unscrew the heatbreak from the heatsink.

its having to spin the heater block assy i find to be hard on the cables
because is too much clutter below the effector platform (fan, z probe,
possibly LEDs) and I have to bend the cables to the heatblock down for
clearance.
Plus its a touchy process having to spin that hot block around without
burning myself.
As for not leaking around the threads inside, the threaded nozzle would
still screw tight against bottom of the (unthreaded) heatbreak.

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shadowphile
As for not leaking around the threads inside, the threaded nozzle would
still screw tight against bottom of the (unthreaded) heatbreak.

That sounds workable to me, as long as you're careful not to over-tighten and drive the heatbreak out. I shall put that on my list of things to try as I was thinking of making a new block anyway.

I have found that these kinds of clamps are super strong. However, if the material that has to bend is thick and the screws are small it may require an excessive amount of screwing torque to get a lot of clamping, maybe more than the screw can handle. I suggest max screw size and the closest possible pre-clamp fit. The optimum block shape would be thin with the screw away from the clamping center, although too much of this would of course impact the heat transfer properties.
But..I think it is very possible to get so much clamping that over-tightening the nozzle would strip threads instead of pushing out the heat break.

One way to do this would be to have the filament guide run through the heater block as a smooth cylinder with about 3mm of exposed threads on the nozzle end, and 6mm on the feed end.

Then the nozzle would be screwed on to the tube (clamping from the bottom) and a 3mm high nut would screw from the feed side, clamping the top.

The tricky bit would be sourcing a good high viscosity thermal compound to fill the small voids between the heater block and the feed tube.

Heater block maintainance would then just be a matter of unscrewing the nozzle and sliding off the heater block

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frankvdh
Just having a pair of flats or a hex machined onto the heatbreak in the space between heatsink and heater block would make it much easier to unscrew the heatbreak from the heatsink.

supposedly that space is thin for a reason, thats why there are no threads there. the thin metal gap helps block heat travel. thats the theory at least, i dont think it really works in practice because without the fan the heat sink will still get hot as blazes.

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thetazzbot

Quote
frankvdh
Just having a pair of flats or a hex machined onto the heatbreak in the space between heatsink and heater block would make it much easier to unscrew the heatbreak from the heatsink.

supposedly that space is thin for a reason, thats why there are no threads there. the thin metal gap helps block heat travel. thats the theory at least, i dont think it really works in practice because without the fan the heat sink will still get hot as blazes.

Reminder : not only blocking it away from the cold end, it also keeps the heat in the hot zone as much as possible, making the thermal transition sharp. If you have a smooth temperature gradient on a long distance you will get melted plugs problems I believe.

---

Most of my technical comments should be correct, but is THIS one ?
Anyway, as a rule of thumb, always double check what people write.

Sorry, am I missing something here. Why dont you un-clamp the heater cartridge and un-screw the thermistor screw and remove it. No cables to twist around then as you remove the block ??