Stream of I3V 12" Build Consciousness

[lakester]

I wish I had some clear insight to share regarding the results of the retraction tests. Instead, some observations...

Both PLA and ABS exhibited the same issues, though ABS to a significantly lesser degree.

In both cases, regardless of varying temp and retraction settings, the same effect was seen, which was the formation of branches on the start point of a perimeter. Retraction settings DID make a difference, but not a huge one.

As a result of earlier tests, I decided that adding a part cooling fan might be interesting. They were interesting all right, but in completely the opposite way I was thinking. More on that in a bit.

While I have a long series of photos taken with prints done with different settings, there really is not sufficient difference to to justify posting them all here. So I'll just post one photo the exhibits the general problem, as well as the "surprise" related to the part cooling fan.

20150518_112239.jpg

The object on the left is rendered with the part cooling fan off. The object on the right (surprise!) was rendered with mostly the default auto-fan settings (which basically just result in the fan being cranked up to full speed for every layer after the first). All other settings were identical between the two tests. Material was PLA.

While I don't have any photos to illustrate, the fan was DEFINITELY a help when it came to bridging. Haven't experimented with that specifically yet, but I do notice that the fill layers rendered on top of the infill honeycomb exhibit virtually no sagging, i.e., the resulting surface is pretty dang flat.

Along the way, I did some reading. Naturally, ideas were expressed that were in complete contradiction with one another, so it was kinda hard to get a read on what was going on based on someone else' experience.

One of the things that seemed worth doing was checking my extruder calibration. It was dead on. (Heh..., actually a little surprised about that).

I tried a print using fan settings clough42 mentioned over in the itty bitty thread. Exact same results, though I kind of expected that.

Read some stuff that made it pretty clear that part cooling fan shroud geometry and the specifics of the airflow can have a huge effect. I.e., it ain't an all or nothing kind of thing.

Etc.

Conclusions:

• The retraction test is possibly a degenerate case, or at least a corner case that may not be entirely relevant to what I want to do with this printer anyway. It's still a challenge for me, but it ain't the end all be all...
• For future research: how to best manage cooling for layers with many perimeters, because I think that is a relevant special case, and the Slic3r auto-fan settings aren't really up to it.
  
  • Read about direct rendering options that bypass a slicer altogether. Wonder if this puts in place a better situation wrt automated analysis of cooling needs, since the print path can be altered in ways that aren't really possibly when slicing.
  
  
• The results may suggest OVER cooling, even with the part cooling fan off (remember that stock MF HE fan shroud..., it blows down onto the part).
• I think it is worth trying clough42's HE cooling shroud.

[lakester]

20150517_191939.jpg

As part of the aforementioned and quasi-ill-fated though educational retraction test, I added clough42's part cooling fan shroud.

I used the stretched version so as to be able to continue to use the existing MF HE cooling shroud.

After the 24mm test cube, this was my first print w/ ABS. Well..., actually..., I attempted this several times in a couple of situations, and got some ABS schooling. In the end, I added ears, and printed the part by itself rather than with a group of parts.

Apart from learning about ABS, some things didn't go according to plan.

Well..., one exception..., it did just work with the RUMBA..., no fussing around. Oh..., some of the spares that were shipped w/ my kit were handy. Like a spare fan!

But in every other way..., it was "interesting".

1. I spent waaaaay too much time shuffling around town to try to find some metric stuff (drills). Gave up and made do.
2. I got cocky with pronterface and ran my x-axis past x-max. Badness occurred..., but I gotta say, the high repairability of the printer actually made it easy to fix.
   
   1. Just the same..., an x-max limit switch is in this printer's near future.
   
   
3. Discovered a problem w/ my y-limit switch and my y-bed in general. Will post on that in the future.
4. When all was said and done, got completely the opposite results I was hoping for. I think that will be a good thing.

Per the previous post, gonna start the process of installing clough42's HE fan shroud. This will mean printing the standard length version of the part cooling shroud, as well as the new piece. As I recall..., I have to get a new fan as well..., so will research that a bit.

There are a couple of pottery related tools I want to make for use this week..., so the new-new shroud project may wait for that.

[Hankus]

Speaking of printing printer parts, I recently printed a set of spare parts for my i3v 10" with hexagon hot end. When I printed the extruder piece, I noticed that a couple of locations on the bed lifted after maybe 10mm or more of ABS 3mm had been layed down. I reprinted the same extruder with another brand of ABS to see if that made any difference, but the same lifting occurred. But what really gets me is when I look at the piece supplied by Makerfarm and currently being used, it has the same evidence of lifting with the exact same resulting curved surfaces as those printed by me. This would indicate a common problem and seeing how STUCK the ABS remains to a heated bed, makes me believe that cooling of the ABS is causing the lifting or the mass of ABS itself draws more heat than the bed can maintain.

[lakester]

Yup. I saw the exact same thing.

As part of my "well..., while I have ABS loaded, might as well as use it" theme, I printed off the extruder pieces.

I didn't really notice it until long after removing it from the bed, but the main extruder structure had warped significantly on the table facing side, on the arm that mounts the upper right corner of the motor.

And yup, the MF supplied part has the exact same problem.

Heh..., the reason it all seems to work, in my case anyway, is that magically, the side on which the motor mounts is straight and true. Now THAT, I don't get.

FWIW, I was experimenting with different bed temps. I THINK that for the extruder parts I started at 110C, and after a few layers, backed it down to 84C..., or possibly 90C. The prints (of other things) that I left at 110C tended to exhibit spreading on the bottom layers over time.

I also found it useful to print difficult (ABS) parts by themselves rather than in groups, in order to "keep the heat on" each layer as long as possible, without long wait times as the machine went to render the perimeters of other parts.

One thought that has crossed my mind is the possibility that an enclosure might be useful.

Speaking of printing printer parts, I recently printed a set of spare parts for my i3v 10" with hexagon hot end. When I printed the extruder piece, I noticed that a couple of locations on the bed lifted after maybe 10mm or more of ABS 3mm had been layed down. I reprinted the same extruder with another brand of ABS to see if that made any difference, but the same lifting occurred. But what really gets me is when I look at the piece supplied by Makerfarm and currently being used, it has the same evidence of lifting with the exact same resulting curved surfaces as those printed by me. This would indicate a common problem and seeing how STUCK the ABS remains to a heated bed, makes me believe that cooling of the ABS is causing the lifting or the mass of ABS itself draws more heat than the bed can maintain.

[Hankus]

Yes I thought the same thing about the extruder with regards to how fortunate that motor side was straight. And yes I also tried printing multiple pieces and had poor results and came away with the same thought.

The enclosure idea is one I'm working on now. Have all the materials purchased and now just trying to find the time to work it into my schedule now that the weather around here has improved to the point that outside projects now have priority. I plan to follow the design of this Youtube contributor who also has a Makerfarm i3v 10".

https://www.youtube.com/watch?v=gkicD2RMveE His final design was shown in this video https://www.youtube.com/watch?v=TIWCAOSgp8Q

My cabinet will share the same basic shape, but I also plan to build mine with a base so I can move the installed printer about without much problem. Maybe a couple of hand grips on the sides for ease of holding.

[lakester]

That voice sounds familiar..., I think he has another vid as well somewhere. Heh..., OK..., now I need a CNC router...

The base with handles sounds like a good idea.

...

The enclosure idea is one I'm working on now. Have all the materials purchased and now just trying to find the time to work it into my schedule now that the weather around here has improved to the point that outside projects now have priority. I plan to follow the design of this Youtube contributor who also has a Makerfarm i3v 10".

https://www.youtube.com/watch?v=gkicD2RMveE His final design was shown in this video https://www.youtube.com/watch?v=TIWCAOSgp8Q

My cabinet will share the same basic shape, but I also plan to build mine with a base so I can move the installed printer about without much problem. Maybe a couple of hand grips on the sides for ease of holding.

[lakester]

So after a frustrating bit of bed leveling following the install of the parts cooler, and the discovery of "issues" w/ my build table, I decided to upgrade the z end-stop to something a little more useable.

At first I tried to modify clough42's original design to work with the 12" I3V, but FreeCAD was giving me too much difficulty. Between outright crashes and hangs, and really out of date docs, I just decided to make do with clough42's original design, hacked with parts I could get at my local, rural, Ace Hardware.

Though the results aren't optimum, they work waaaaaay better than even the updated MF design.

This will be my last fiddling with z end-stop adjustment prior to adding some form of ABL.

20150520_133606-small.jpg

[lakester]

The extruder cable bundle was just bug'n me (and my X end-stop and RH Z rod).

Finally had a chance to do a complete "thing" from scratch. The jury is still out w/ FreeCAD, but it cooperated this time around.

I don't have the the swanky CAD skills of most of ya, but it works dammit!

20150521_200727-small.jpg20150521_203602.jpg

Heh..., the irony was I told myself "no cable ties allowed". Ummm..., to hold a cable that is practically made out of cable ties. It was the principle of the thing!!!

[lakester]

Finally have found the answer to a big part of one of my print problems, namely (a made up name...): Post Retraction Start Point Tendrils.

This is the case where the filament is to be retracted prior to a new XY perimeter on the same Z plane (layer), but that by the time the hot end arrives at the new start point, filament has oozed substantially enough that it contacts a lower layer on the approaching perimeter, beginning the build-up of a tendril.

I distinguish this from stringing in that the hot-end successfully disconnects from the perimeter it's leaving behind, i.e., it's not leaving a trail. It's building a mess on the destination end of the jump.

In a sense, the problem is still a retraction problem, but rather than with the mechanical retraction settings themselves, it's more to do with the temperature of the extrusion. I.e., at too high a temperature, the fluidity of the extrusion is beyond the printer's means to mechanically control. It's gonna ooze no matter what.

I had hesitated playing with extrusion temperatures simply because I assumed they would be relatively well characterized, and at worst, "optimum" would only be +/- a couple of degrees off the Makerfarm default settings for 3mm ABS w/ a Hexagon.

WRONG!!! (Well..., I also didn't want to risk clogging the HE)

While I still think I have more tuning to go, thus far, I'm getting much better results a full 20C cooler (230C) than "factory" settings (250C).

I'm reasonably confident that my thermistor is installed as well as it can be, so any indicator error I assume would be on the lower end of the scale.

Heh..., I had been willing to ignore this problem, but when it showed up in a part (clough42's HE fan shroud) I was planning to use, I decided to play with it some more.

Here are the results thus far:

20150524_110628-small.jpg

The part on the left was printed at 250C, the one on the right at 230C.

Flash photos flatter noth'n..., so I can only say that the part on the right also has a visibly better finish than the one on the left, when compared standing in sunlight.

Not only are the tendrils vastly reduced, but there is significantly less "clotting".

It's interesting. I had sorta come to dislike printing with ABS because when I tested an extrusion, it came out of the HE almost like it was burnt. It didn't seem to flow nicely, the way PLA was doing. As I lowered the temp, the extrusion flow/quality just got nicer and nicer.

As for the actual retraction settings, I've settled on 2mm @ 30mm/s for the time being. The MF settings were 1mm @ 30mm/s, and I had tried increasing the length and slowing the rate. What seems to make the most diff is the length, so I've bumped the rate back up to the original numbers and that seems to be working well.

I'm gonna try a jump down to 220C and see how that goes. Who knows? I may even like ABS after this.

[dunginhawk]

ive been one of those people that has largely liked ABS much more than PLA for over a year now. I think 250c is WAYYYYY too hot for most anything ABS. I print at 230, even down to 225 depending on filament color, brand etc.
250 creates a molten liquid way less viscous than it should be... stick with the LOWEST possible temp you can.