Trick Laser hot end progress

[geneb]

Is it just me or is the center hole WAY off?

g.

[Eaglezsoar]

Is it just me or is the center hole WAY off?

g.

Gene, I'm beginning to think that you are way off! I did get a chuckle out of it though!

[geneb]

Oh hell yes. I'm out of round too.

g.

[Gr8Scott]

Thanks for all your helpful comments and suggestions!

Yes, I definitely want the I.D. of tubing to have a smooth taper to the orifice opening.
From 2mm to .35 mm in distance of 4mm is what I am shooting for.

If the filament can be kept well below it's softening point up to a short melt zone, I speculate the retract will work better.
Also hoping the smooth slow tapered I.D. at end will have less back pressure. Maybe even drool less, therefore needing shorter retracts.?

With my J-Head and ABS it seems to have better more predictable retracts with fan on hot-end ALL the time, keeping it really cool.
Could it be that the ABS is soft and stretchy some distance before the melt causing issues because it stretches thin on retract the balls/jams just a bit when restarting extrusion?
I do not *have* to run fan with ABS, but it works better I think.
PLA's lower melting point may just make it more of a problem than ABS/

~*Brian

I am curious. How does one go about machining a smooth inner transition like the one you mention above? Grind down a nice sharp drill bit to have a pointy end?

[626Pilot]

When's this gonna be ready? I'm stuck using the stock hotend for PLA, hot-ends.com is out of stock, and I am dying to get this thing actually printing.

[Broose]

hot-ends.com is out of stock

Did you check the site at noon on Friday? That's when they take orders. I was able to order one a week ago Friday and it was shipped last week to me.

[Eaglezsoar]

hot-ends.com is out of stock

Did you check the site at noon on Friday? That's when they take orders. I was able to order one a week ago Friday and it was shipped last week to me.

Broose, did your hotend from hotends.com have 4 slots and a little shorter than what you expected?

There was a discussion at http://forum.seemecnc.com/viewtopic.php ... 561#p14561 we are trying to figure out what is going on because the
standard calls for 5 cooling slots. Just wondering what you received.

[Broose]

Broose, did your hotend from hotends.com have 4 slots and a little shorter than what you expected?

There was a discussion at http://forum.seemecnc.com/viewtopic.php ... 561#p14561 we are trying to figure out what is going on because the
standard calls for 5 cooling slots. Just wondering what you received.

The hot end shipped and I think it has already arrived at my office but I haven't been there for a few days. I will be back tomorrow and can check the dimensions as soon as I get there.

[Flateric]

I think the really slippery liner is one of the primary reasons Jheads are so very good at PLA. So slipery in fact that during the swelling of the PLA it is the slippery surface directing the swell as well. PLA's lower melting point is both a blessing and a curse because of this attribute.

I find all metal hotends, and I personally own every one of them that I am aware of, really shine when it comes to high temp plastics like Polycarb (265-285c), high impact crystal clear ABS (265c), nylon 618/645(varying temps but all well above PLA) and of course "regular" ABS. But one thing all of these plastics do not do that PLA does is swell and become grippy and rubbery like PLA. You can generally just up the temps to clear jams which is the exact opposite of clearing jams with pla.

A PLA jam can be such a major PITA to clear in comparison to the others. PLA's swell, rubber and high friction states at certain points make it an almost requirement to have a slippery liner for protection against jams.

I have printed PLA with an all metal hotend, but your acceptable temp range is painfully slim and combining this with retraction and extrusion pumping it becomes smaller. PLA does not discriminated about what metals it will stick to. It however doesn't stick at all to some slippery linears.

As for my favorite all metal hotends, rather than naming specific ones, I can say that my favorites are generally the ones with the smallest melt zones. I am also experimenting with tips that have a small reservor of liquided as close to the very tip as possible with a tight tolerance around the retracting filament to assist the hydrolic action of the retractions.