Do the dual hotends work better than the v3b?

The official subforum for discussion of the installation and use of the official M2 Dual Extruder upgrade.
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Capt. John
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Do the dual hotends work better than the v3b?

Post by Capt. John » Wed Dec 03, 2014 12:40 am

Still have my dual hot end kit in the box from MG.
What are the advantages in the different type hot ends?

Obvious to color, in my case a easier to remove supports is why I purchased
the dual extruder kit in the 1st. place.

Been hesitant about the end drips, needing wipers and code modifications.
Capt. John
Manistee, Michigan
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Tim
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Re: Do the dual hotends work better than the v3b?

Post by Tim » Wed Dec 03, 2014 1:58 am

As far as the quality of printing, I'd say that the V4 and V3b are very similar. Much of the print quality has to do with the nozzle design. I used to think that the MakerGear nozzle looked sort of large and clunky until I used an E3Dv6. It *looks* better, but seriously, the MakerGear nozzle *works* better. Especially with PET, the E3Dv6 nozzle has an overhang that the plastic loves to stick to, and collect, and grow, until it forms this big wad of gunk and starts interfering with the print. It makes a huge mess all over the MakerGear nozzle, too, but it burns or sloughs off; it doesn't accumulate into a big wad.

The main advantages of the V4 are:

(1) There is a gap between the top of the hot-end and the extruder mount that prevents heat flow and makes it a lot easier to remove the hot-end without having to disassemble everything else.

(2) There is no PEEK, just a PTFE lining, which lets the hot-end get a lot hotter. If you have the dual extruder setup with the all-metal hot-end, it can get even hotter.

(3) Easy vertical adjustment (and disassembly) with the turn of a set screw.

(4) Better airflow with duct guiding the air to the motor gears and the base plate that holds the hot-ends in place. I have no proof that the airflow is better; it just looks more sophisticated. . . : )

(5) Metal motor mount: No possibility of a cracked motor mount. That was the only part of the M2 that was under significant stress and was a 3D-printed part; with the V4 setup, it's all metal, and bolts to the motor. It's not just that the mount isn't going to crack. That motor isn't going anywhere it isn't supposed to.

(6) The nozzles are slightly higher so the vertical build volume increased slightly.

Drawbacks of the V4:

(1) Slightly reduced range on the X axis. The left extruder can span the entire glass plate. The right extruder loses 3cm on the left side of the plate. If you didn't try to modify your M2 to squeeze every last millimeter out of the range, you won't notice anything.

(2) The right extruder can get in the way when you're printing with the left extruder only, ramming into layers that have peeled up slightly (usually because they are on overhangs). Probably best to loosen the set screw and push the right extruder up a little, to stay out of the way when you're not using it. It would be nice if there were a little lever to do this. . .

(3) Advantage #6 means that clips holding down the glass plate in the back can wrap around the hex nuts under the linear X rail. This is very bad for a print. I found out the hard way! The clip looped around the nut and held everything in place like an anchor until the motors managed to rip the clip off. Everything survived except for the print, fortunately. Since then, I have laid the arms flat on the glass, facing forward. I can always remove them if they're in the way of a print.

So, in conclusion---a few weird gotchas, but overall, I very much like the dual extruder V4 setup.

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Re: Do the dual hotends work better than the v3b?

Post by Capt. John » Wed Dec 03, 2014 2:23 am

Thanks Tim for explaining something I don't have a clue about.
Should have some down time in January when I'm done printing ring project.
Then, I'll swap over to the newer setup.
Capt. John
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Re: Do the dual hotends work better than the v3b?

Post by Tim » Wed Dec 03, 2014 2:45 am

Assembling the dual extruders was mostly worry-free. The biggest hassle was the wiring. The wiring harness squeezes very (very!) compactly into a tight space behind the motors, which is unnecessary, as there is plenty of space back there. No real need to conserve it other than to keep everything looking tidy. Which it does. But at the cost of an annoying experience of cramming all the wires into the right slots, several times, until eventually everything squashes together the way it's supposed to.

There's a set of clips at the bottom of the printed part that is the cover for the wiring behind the motors. The various wire ends are supposed to feed through these. I found them about as useful as the plastic racks that come in the Christmas tree light boxes are for holding the light strings. I eventually abandoned them completely and just used a lot of wire ties to keep the wire ends together and in more or less the right place.

Everything else went together as advertised. I had a bit of extra work to do myself, because I was upgrading from the split 19V-12V supply to the single 24V supply at the same time.

Oh, one other thing: I found that the 2nd spool holder was too low when it was mounted where it is intended to go. It probably has to do with some of the older filament spools I have, but they were extending far enough down for the rim of the spool to catch on one of the bolts that holds the electronics enclosure. So I moved the spool holder up by putting the bolt through the hole on the right side of the spool holder bracket instead of the one on the top. My spool holder bracket is therefore only attached to the frame on its right side. Because it naturally wants to twist counterclockwise to fall back to its original position, I put an extra machine screw through the hole on the bottom. It's not attached to anything, but the nut rests against the frame and keeps the bracket from turning. I will probably just print the nice alternative spool holder that has been mentioned in the forum before, to replace the one that came with the dual extrusion upgrade.

I also think that the filament guide for the spool on the right side should be sticking out the back of the M2, not to the right. Preferably it should be hinged like the other filament guide so that it can swing back and forth depending on where the filament is rolling off the spool. I will have to sit down and design one, soon.

hybridprint
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Re: Do the dual hotends work better than the v3b?

Post by hybridprint » Mon Dec 15, 2014 4:29 pm

is the v4 all metal basically the same as the E3D-V6 ?

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Re: Do the dual hotends work better than the v3b?

Post by Tim » Mon Dec 15, 2014 5:27 pm

is the v4 all metal basically the same as the E3D-V6 ?
No, not really. The v4 nozzle is the same design as the v3b (from the outside, at least); there are only a couple of cooling fins (rings) compared to a long stretch of a dozen on the E3Dv6, and the ones on the v4 look quite precision-machined by comparison. The most significant difference is the air gap at the top of the heatbreak on the v4. The top of the heatbreak is clamped into a machined bracket that has a fan duct sitting on top of it, blowing air directly onto the bracket. But above the bracket is a gap of about a mm before the printed plastic extruder mount, which is totally unlike either the v3b or the E3Dv6, and a real benefit when trying to disassemble the extruder.

I can't speak for what's inside the nozzle. E3D touts their v6 as being polished on the inside of the nozzle, which they claim helps a lot with avoiding clogs, especially with flexible filament. I did encounter clogging with PLA in the all-metal v4, but as I have not used either the all-metal v4 or the E3Dv6 very much, I wouldn't try interpreting that as anything more than anecdotal evidence---it happened once to me, on one of them.

hybridprint
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Re: Do the dual hotends work better than the v3b?

Post by hybridprint » Mon Dec 15, 2014 5:38 pm

thank you! any experience with ninjaflex on the v4? I heard that stuff is very challenging.

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