30x30 test cube with a 1.2mm volcano

Discussion in 'Show off' started by Spoon Unit, Mar 27, 2016.

  1. Spoon Unit

    Spoon Unit Well-Known Member

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    After some successful vase printing with the 1.2mm volcano and some dual printing shenanigans I wasn't so happy with, I decided to try something a little more normal. @Chase.Wichert had been complaining of the nozzle not restarting after each move so I wanted to see how to nail that. And @R Design was complaining of some Z artifacts every X layers, so I wanted to see if I had the same problem.

    I ran this test with Rigid.Ink black PLA. Nozzle is 1.2mm. Layer height 0.6mm. First layer printed at 225c with a first layer height of 99%, with 50%, speed 50% (of 3000 mm/min). Agressive cooling with layer 3,9,15 at 40,60,80% respectively. I chose a single base layer. 1 shell. and 2 top layers, with a 15% rectilinear infill. To try to address the problem of @Chase.Wichert I chose an agressive 0.8mm restart distance.

    Results:

    2016-03-27 19.06.34.jpg 2016-03-27 18.57.25.jpg 2016-03-27 18.56.38.jpg 2016-03-27 18.55.09.jpg 2016-03-27 18.52.34.jpg 2016-03-27 18.48.39.jpg 2016-03-27 18.48.25.jpg

    Even with 0.8mm, the seam is very present, but it does seem to be starting pretty much where it needs to be. The head just moves on a little too quickly. In theory 0.8mm should be enough for the material to hit the floor, but I think we'll need a larger number yet. I'll try a full nozzle diameter of 1.2mm next.

    Looking front on in image 2 you can see how horrible the top is. In essence, it looks like such thick dollopy plastic doesn't set quickly enough (and I'd put the fan up to 100% by this point partly as a test and partly to make sure the top layer had max cooling) to cover a 15% infill or connect well enough at 15% overlap to a single outline. I'm not sure whether to try two outlines or a bigger overlap. Another thing I noticed is that, being a normal infill layer, the top two layers seemed to go really fast, even the outline. So possibly a slower speed would help.

    The next three shots show pretty great dimensional accuracy and, as you can see from the last two, the layers are accurate and look great one on top of each other.

    This also printed pretty fast in just 15 minutes. The top layer aren't good enough for me to let it loose building RichRap's printer boxes, but a few tweaks and we could be there.
     
    mike01hu likes this.
  2. JvdP

    JvdP Well-Known Member

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    Whooo, shiny!

    Good looking layering. What's that slight banding/ribboning pattern on one of the corners?

    Give it a go with 3 or 4 top layers. I'm sure it will be smooth then.
     
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  3. Kanedias

    Kanedias Well-Known Member

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    I wonder if faster might not be better for the top. Whip it across before it drops.

    I've ordered all the missing bits to make a whole second hot end for the volcano before I start experimenting.
     
  4. Spoon Unit

    Spoon Unit Well-Known Member

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    @JvdP that's the seam. I've improved on that a lot since then, but struggling with the top layer. Will try your idea @Kanedias and perhaps try a bit more speed on the top. No way I'm printing anything big until I figure this out. Happy to print a bunch more 17p tests. For subsequent test, I've reduced the height to 6mm, which is enough to see issues with top layer.
     
  5. mike01hu

    mike01hu Well-Known Member

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    Love the accuracy but the top needs attention. @JvdP 's advice to use more top layers sounds good to me but the extrusion width looks narrow.
     
  6. Spoon Unit

    Spoon Unit Well-Known Member

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    One things for sure with this thickness of material. You just cannot use an infill mode where multiple angles print on each layer.
     
    #6 Spoon Unit, Mar 27, 2016
    Last edited: Mar 28, 2016
  7. Spoon Unit

    Spoon Unit Well-Known Member

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    Finally got a good top. Interestingly this was a sort of accident as I'd tried adding a second process in order to print two shells on the top layer. That didn't work out so well, but the top layer was effectively a new first layer and as a result printed at 50% speed, which really seemed to work. I think that slower pace is also what's making the first layer fat and squashed. Anyway, have a look at the 8 prints it took me to get there, some of which were killed before they completed...

    2016-03-28 00.08.59.jpg 2016-03-28 00.08.47.jpg

    I'm thinking an ending script which lifts would be good too.
     
    Sanjay likes this.
  8. Chase.Wichert

    Chase.Wichert Well-Known Member

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    So, since we talked last, I moved to a .8 nozzle, and I disabled force retraction between layers. This has helped with the giant gap I have been getting, also what has helped is two outlines, inside out, so if there is a seam, it is hidden by the outside layer, I am no having trouble with layer adhesion, I am essentially making a large rectangular tray with largely radius end corners, and the layers are separating in the radiused corners... In order to combating this, I put a box over the BB and enclosed the sides, I turned off the fan (this is ABS), increased the temp to 250c, made it solid infill, and slowed the print from 70mm/s to 50mm/s... Hopefully this works..
     
  9. Spoon Unit

    Spoon Unit Well-Known Member

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    Yeh, I've also messed with disabling retraction, but while that gets rid of the gap, it does create a more messy start/finish outline area. Ok, so you solved that by doubling the perimeters, but that adds significantly to the total plastic used and thus weight and strength. I saw your picture with the box. Looks like some of your issues there are ABS related. I hope it works out for you.
     
  10. mike01hu

    mike01hu Well-Known Member

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    That looks so much better, so will you summarise what you have done.
     
  11. Spoon Unit

    Spoon Unit Well-Known Member

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    Eventually, yes @mike01hu , when I actually get to a conclusion. My purpose for creating all the small squares was in preparation to build RichRap's BB printer boxes. I just put that print on and uncovered some more issues. It looks like the the whole system is just not able to feed out a consistent 0.6mm layer at the speed I have for infill which actually looks like it's on 3000mm/min. I think that's my default print speed. Doesn't look like there's a standard infill speed. At some point, the system just stopped feeding filament (possibly I even heard a snap. I'm wondering if the pace of feed led to the PTFE being sucked into the heat sink due to drag and has again created too small a hole. It sounded like it wasn't happy in any case as the hobbed gear was spring back, meaning it just couldn't feed the filament in at that pace. I'm now thing that a 0.6mm layer is not a good choice for large builds, or maybe I just need to down the speed. Perhaps i'll pull back the speed a touch and bring the layer size down to 0.4.
     
  12. mike01hu

    mike01hu Well-Known Member

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    I'll look forward to that:).
     
  13. Stefan

    Stefan Well-Known Member

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    maybe a dumb question but with the standard v6 what is the biggest nozzle diameter?
     
  14. Spoon Unit

    Spoon Unit Well-Known Member

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  15. R Design

    R Design Well-Known Member

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    I think we know that Richrap uses (exclusively) a 1mm nozzle with 0.25mm layer heights.

    So that's how he'll have printed his boxes.

    The real question is the following: is it possible to print more than one box at a time?

    Reason being, now I've graduated from cubes to printing a bigger part, discover that there's a MASSIVE amount of ooze.

    Setup: 0.8mm Volcano, 0.3mm layer heights: 0.4mm Z lift + 140mm/s XY speed

    If the printhead has to jump 10-20cm there's 2-3mm of ooze hanging off the nozzle.

    Right now I'm only using a 0.4mm Coast setting.

    Frankly, don't know where to start.

    On the speed front: what's the max XY speed before artefacts start to appear?

    Z lift: I'm still on the slow (3mm/s) Z: flashing up to 16mm/s will improve things a bit.

    But what about all the various retraction settings?

    I propose a new version of the Cube challenge: two cubes, placed at opposite ends of the print bed!

    ps I am, as ever, working with XT. Having earlier determined that nozzle 255C was better than 240C because it eliminates clumping around the nozzle, now am learning that reducing the temperature can improve ooze. Earlier also noticed that at 260C, when moving slowly, the extrudate starts to sort of foam and afterwards has a glassy appearnce: a clear sign of the extended meltzone taking its toll. Reducing to 255 did the trick.
     
    #15 R Design, Mar 28, 2016
    Last edited: Mar 28, 2016
  16. Spoon Unit

    Spoon Unit Well-Known Member

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    @R Design I like your challenge. A cube at the farthest corners. Will take you up on that.

    All the testing on the small cube was, for me, to learn what parameters to use to print out RichRap's boxes. After two failures, one terminated by me as it didn't look great and the second terminated by a thermal runaway (really cross with myself for attempting 100% fan on layer 24 - slap wrist), I finally got it printed. It's not a thing of beauty, it more of a log file of lessons. However, it is functional and won't get re-printed.

    2016-03-28 21.46.51.jpg 2016-03-28 21.46.37.jpg 2016-03-28 21.45.52.jpg
     
  17. R Design

    R Design Well-Known Member

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    Good effort @Spoon Unit .

    Layers are nice and top looks solid.

    I've just re-examined RichRap's photos and noticed the relatively fine infill pattern under the top layer around his SD card holder.

    I wonder if he used a <100% infill extrusion multiplier which would prompt S3D to increase the number of lines in order to maintain the same infill percentage?

    That's a good trick.

    Since we know he used a 1mm nozzle and that the walls of the box are 2 perimeters, assuming he used an extrusion width to exactly match the total wall / 2, we can calculate his principal extrusion width.

    Then by counting the number of lines of rectangular infill in the top surface, we can fiddle with the infill extrusion multiplier and infill percentage in order to get the same result.

    Just an exercise. Of course you were going for a different "look", but extra lines in the infill does help with the "top" problem.
     
  18. Spoon Unit

    Spoon Unit Well-Known Member

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    Not a bad idea there on infill extrusion width. It's just a shame you can't apply this kind of thing to just the topmost layer. I've come to the conclusion that 3 top layers are required to build enough foundation to make that top layer good. Reducing the extrusion width for the top layer sounds like an idea. Looking at his prints, I don't think he did that though. It is puzzling that there's a crisscross design on top, but that could be related to the material being used, saying that the layer below is also appearing through the top layer. I keep in the back of my mind that he's probably printed about 100 times as many objects as me so has the experience to make adjustments much more quickly than I currently can.

    As you say, it does look as though he's got a 1m outline as his primary design, and this tells a story about how model design and nozzle size can go hand in hand.
     
  19. R Design

    R Design Well-Known Member

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    I think he's reduced the extrusion width for the regular Infill: which means instead of a very few chunky squares he's got lots of smaller squares made of narrower fibres. Those narrow fibres are cutting through his top layer. Suggesting also that he hasn't opted for (or needed to opt for) 10 top layers as a workaround!

    - I'm not sure if the Infill Extrusion width influences "Solid Infill (aka top and bottom layers as I just learned in that other thread!)"

    - Another reason for gaps appearing in the top layer - specifically gaps between parallel tracks - can be the top layer "sagging" because of the nature of the infill below. A finer mesh helps, methinks.
     
  20. Alex9779

    Alex9779 Moderator
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    No it does not have any influence on that.
    For solid infill layers the extrusion width from the "Extruder" tab in millimeters is used...

    There is no settings in S3D actually to control the solid infill extrusion width individually or an overlap/spacing of those solid infill lines. This would make life a bit easier...
     

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