Poor quality prints (PLA) - any ideas?

Discussion in 'BigBox General Chat' started by Proto_BB, Aug 10, 2016.

  1. Proto_BB

    Proto_BB Well-Known Member

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    I have not yet been able to get a high quality print out of my BigBox 1.1 running RC6. I have checked the Simplify3d page and can't see the issue I'm having. I get really rough outlines and bottom layers and pretty poor layers from there on. I mesh level the bed (and store to memory) before every print. For whatever reason I still get rough prints.

    Things I have tried:
    - Bed temps from 50 to 60 degrees
    - Hot end temps from 200 to 220 degrees
    - Different brands of PLA (Verbatim & E3D everyday)
    - Did the test 100mm filament extrude/measure and tweaked settings

    I have no idea if what I'm seeing is typical "under extrusion", "over extrusion", "nozzle too close to bed" or some other issue.

    [​IMG]

    [​IMG]
     
  2. Tom De Bie

    Tom De Bie Well-Known Member

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  3. Proto_BB

    Proto_BB Well-Known Member

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    Yes, I mentioned I checked it in my second sentence. I have checked it multiple times and the reprap trouble shooting guide. I have not seen anything that looks the same. I may be misreading their photos.
     
  4. TimV

    TimV Well-Known Member

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    What model do you run?
    What are the z axis esteps tou have configured? + what motor do you use (1.8 or .9)
    E3d everyday prints almost perfect at the default settings given on the sd card and on the wiki page.
    Could be slipping of the filameter or a blocked extruder. Did you clean it already?
     
  5. mike01hu

    mike01hu Well-Known Member

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    It looks like over-extrusion, so check your extrusion e-steps calibration. A quick check while printing is to reduce the flow rate under the LCD/Tune options to see if this helps. For first layer tests on new filaments I print a single layer-disc, 30mm diameter with rectangular fill pattern.
     
  6. Sarah Nicholson

    Sarah Nicholson Well-Known Member

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    Looks like the nozzle might be slightly too close to the bed too so you're getting uneven extrusion from the pressure in the nozzle and also roughness from the nozzle scraping the previous layer. Try adding a small amount of positive Z offset in the Gcode tab and see if that helps at all.
     
  7. Old_Tafr

    Old_Tafr Well-Known Member

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    Do you get this effect on the last few layers as well as the first?

    I posted similar a few months ago.

    Changing the "Flow" on the Tune (second option down changes from calibrate? to Tune once the print starts) menu to in my case 94% solved this. This is better than changing parameters in s3d as you can change the flow rate on the fly from the front panel. It takes a few layers to take effect.

    I have seen a post saying that the nozzle pushed an ever increasing blob in front of the nozzle, which at some point (the blob not the nozzle :) ) detaches and of course sticks somewhere on the print to be picked up later. This was put down to printing speed being too high. This was a similar if not the same effect (blobs) I had.

    I had previously tried adjusting retraction without success.

    See s3d page on faults under blobs and zits, pr pimples or summat.
     
  8. Jasons_BigBox

    Jasons_BigBox Well-Known Member

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    Hi Proto_BB,

    I've been printing a lot of parts in the past week with white Everyday PLA and I've been getting some of the inconsistency that you're seeing. I was going to post some pictures myself (will do tomorrow). I've found that my base layer is often made up of strands that don't quite meet (nozzle too far from the bed?). In that case the finished part is often decent, not fantastic but OK.

    The other times, on the first layer, the outside is nicely 'squished' and very neat but the infill ends up blobby with a rough surface. I assumed it was over extruding but on the infill only?!? A few of my prints look exactly as yours in the second pic.

    I'm running std firmware at present and Simplify 3D with the setup file downloaded from the GitHub site. I have tried tinkering a little to reduce the print speeds, I thought they were the cause of some of the roughness but now I'm not so sure.

    I've swapped to black material today to see if that's any different. I was getting great prints at first from the free sample material (yellow and red) maybe I'll go back to that......

    I'll try to post some pics tomorrow, in a separate post but will link here too.

    Cheers

    Jason
     
  9. mike01hu

    mike01hu Well-Known Member

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    I have said many times on the forum that white PLA has been my bogey filament (cheap or expensive), causing more trouble than with any other, and black and silver PLA have performed the best. It is something to do with the colour filler used I suspect.
     
  10. Jasons_BigBox

    Jasons_BigBox Well-Known Member

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    Thanks Mike,

    Yes, I'd been told something similar, that white is not good to print with. I'm finding it terribly inconsistent, Can have a decent print one day then horrible the next. Here's a few photos:

    Overhang test, pretty good print. good overhangs up to 75degrees but a strange line (just above the degrees symbol on 15)

    DSCF1138.JPG

    Same line inside too. It's as if those few layers were over extruded but then normal service was resumed.....
    DSCF1137.JPG

    Building a mount for a camera, this one shows the same as Proto_BB, Pretty untidy. Printed vertically as one of the other parts needed it. In the end the tall thin part became detached and the print failed.

    DSCF1135.JPG

    The same camera mount but printed horizontally. This is the first layer I was writing about yesterday. It's tidy and the print is overall quite good but there's quite a lot of gaps in that first layer. Too far from the bed?

    DSCF1132.JPG


    Can anyone recommend settings for White Everyday PLA? I'm trying to use 210 nozzle, 60 bed and been tinkering with speeds but to no real success.
     
  11. mike01hu

    mike01hu Well-Known Member

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    Are you using the Titan or original extruder?
     
  12. Jasons_BigBox

    Jasons_BigBox Well-Known Member

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    Titan on a v1.1 Pro.
     
  13. mike01hu

    mike01hu Well-Known Member

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    Have a look at the hob to check if you have the latest version i.e. a broad pattern; there are pictures somewhere on the forum showing the problem. Also, do ensure the PTFE tube is inserted fully into the lever so that it protrudes from the bottom just above and clear of the hob, if it isn't the filament can ride to one side of the hob groove and back, so altering the feed rate. I cut a slight angle on the end of the PTFE to ease fitting.
     
  14. Jasons_BigBox

    Jasons_BigBox Well-Known Member

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    Thanks Mike, that sounds a promising explanation to me. I have the 'good' hob for sure and have cut an angle on the ptfe tube as I found it tough to insert in the top of the Titan BUT I've not been as careful getting the tube fully engaged in the top recently.

    I've had a couple of jams in recent days too. I'll double-check it all again tomorrow. It would make sense if the filament was running on the smooth part of the hob as when I checked, the hob was still driving but there were no marks on the filament. I'll clean the hob out with a pin too.

    Cheers guys


    Jason
     
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  15. Proto_BB

    Proto_BB Well-Known Member

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    I made changes as suggested. I extruded 100mm of filament and measured. It was ~103mm. I made adjustments to the esteps, did the test again, tweaked and I ended up with a decent smooth bottom outline.

    IMG_4523_PNG.png

    The issues with the layers still persist however. Almost looks like air bubbles or something like it. The Verbatim white PLA has definitely been "boggy". I'm almost to the point where I write it off as bad filament. I have some E3D everyday PLA in white and some Torwell PLA in white on the way. I will test those two and see how I go.

    I will report back when I test with the results.
     
  16. Proto_BB

    Proto_BB Well-Known Member

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    This may well be part of the issue. My PTFE tube would not go in. I let it sit above the lever. After reading this I have cut a "v" in the tube to get it into the lever. Hopefully that helps...

    I have also had quite a lot of broken filament. The white Verbatim was broken in multiple sections at time. Usually when I leave it to sit over night. I come back and it can be broken where the hob is and in 3 or so places in the PTFE tube. No idea why it would break when sitting over night. It might have been when I do a small 1mm retraction at the end of the print.
     
  17. mike01hu

    mike01hu Well-Known Member

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    That can be a sign of water absorption, so I suggest you bake your filament for a couple of hours in a very low oven or in a cardboard box on top of your heated bed at 60C; it would also contribute to your quality issue. Hydroscopic characteristics of filaments is important and PLA is one of the worst so it is best to put it away after a print run, preferably in an air-tight box with a silica gel desiccant.
     
  18. Proto_BB

    Proto_BB Well-Known Member

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    It definitely pops throughout the print. I was not aware that PLA absorbed moisture. I had read about nylon moisture issues, but had no idea that PLA was susceptible. When I received this PLA the bag did have a tear in it, but I was not overly worried at the time. With that all said, I also had difficulty with the black PLA from the same manufacturer which did not have a torn bag.

    I will give the white PLA a bake in a low oven and see how it goes. I have a little sandwich oven that I have used to dry sand. I will see if I can set it low enough, or prop the door open...
     
  19. mike01hu

    mike01hu Well-Known Member

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    Have a look at this article.
     
  20. Henry feldman

    Henry feldman Well-Known Member

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    @mike01hu one question I have with that, is how does one unload/load? Because of the natural curve filaments have I rarely get it to go into the hole below the hob without some twisting back and forth and the only way to do that is remove the PTFE like we did on the V1 direct. Did I miss something here in the transition to Titan?
     

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