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Topic: Please help me find all that's wrong with my first print! (Read 1063 times) previous topic - next topic

  • BobC
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Please help me find all that's wrong with my first print!
Hi,

After doing a few 1-3 layer prints to calibrate the printer (and use up some of the questionable white filament that came with it), I just completed my first "real" print on my 101Hero: a tiny phone stand.  The print is completely functional, but is far from perfect.

Setup:

My 101Hero arrived with a bad motor, which I replaced with one from the Stefano group buy (best move ever).  I probably should replace them all, but I want to see how long the other two original motors will last. I had to swap the pink and orange wires in the connector to get it to rotate in the right direction.

I used the horrible yellow tape that came with the printer to cover the build plate because the blue tape I had was dried out and I didn't want to wait to get more.

I added rubber bands to the arms to reduce the looseness/shakiness of the print carriage.  The arms are so flexible that putting the rubber bands in the middle caused bending (which would throw off the geometry), so I put them up near the top of each arm pair.  The rubber band tension was as low as I could get it and still have them stay in place.

I used this PLA filament from Amazon because I could get it delivered the same day for free (via Amazon Prime).  It came well packaged, including a zip-lock storage bag.

I set up Cura using the standard 101Hero config file. The only change I made prior to printing was to make the first layer 50% thicker (rather than do a brim or raft).

I saved the GCode, primed the extruder until the new color came out, then started the print.  I waited four long hours, hovering over the machine like a husband during a delivery.

Print:

The resulting print was strong (good layer adhesion), but does have issues.  Photos are attached.  Here's what I see, and what I think it means.

  • Skirt was almost completely missing, and the little bit that was there was thread-thin.  This happened despite priming the extruder moments before starting the print.  Extrusion rate too low?  Blocked extruder nozzle?
  • Print is fuzzy. I removed most of the fuzz prior to taking the photos, but some is still visible in the interior.  Too little retraction?  Temperature too high?
  • Bottom has a combination of adhesion failure and Elephant's Foot.  Easy: I screwed up the calibration.  And I really should get some blue tape.  Any other factors?
  • Fill isn't tightly joined to outer wall.  Under-extrusion?  Need to increase fill overlap?
  • One layer about 1/4" from the start is totally squished.  Easy: I bumped the printer, hard.
  • About halfway up the whole print steps over a bit.  I didn't have a spool stand and the filament was getting pulled tighter and tighter.  This is when I moved the spool onto a stick.  Any other possible factors?
  • There are small "waves" crossing multiple layers in the later half of the print.  My guess is I still have filament tension problems that will be fixed by getting a real spool holder.  Are there other causes?

Those are all the defects I see (as a 3D printing newbie).  Are there more?  Are the photos good enough to tell?

Here's what's presently on my 101Hero todo list:
- Get blue tape!
- Clean the extruder nozzle (just to be sure).
- Get a spool holder with ball bearings.
- Re-do the calibration using the new filament and spool holder.

Any other changes I should make to my printer?

Thanks!

PS: I posted this here to keep it focused on the 101Hero community.  Should I have posted this on my blog instead, and just linked it here?

  • fedplast
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Re: Please help me find all that's wrong with my first print!
Reply #1
Hi,
Newbie here as well, only have ~10 prints under my belt, all with 101hero.all your assumptions are exactly the ones I would have thought, in fact these are exactly the issues I get in my prints.  few thoughts:
as u mentioned, the slightest bump on the table or tug on the filament will cause enough jiggle to shift the layers. my first mod was adding rigidity to the frame, particularly top and bottom plate. some have added aluminum extrusions and plates, myself I have screwed and glued 3/8 thick polystyrene to top and under bottom ('cause that's what I have access to) and some polycarbonate panels screwed between pylons. I'll post soon.

you mention that to limit the warping on the arms, you placed the rubber bands cloder to the top. isn't the point of the rubber bands to pull them tight? I assumed that we are trying to pull them closer so that they don't have room to wobble. and any change length (which would be really small) we are to compensate with a higher bed leveling. now you making me re-think that...


  • BobC
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Re: Please help me find all that's wrong with my first print!
Reply #2
Well, I did a temperature test tower using its supplied Cura plugin, and learned that the hot-end thermistor (and/or it's calibration table in the firmware) is off by about 20C!

I printed it with 2 layers on the sides (0.8 mm) and bottom (0.36 mm) with an open top and no infill. Since the tower has 8 steps, I used 3C per step to cover 24C per tower.

The first one I did was from 208C (the highest my hot-end will go) on the bottom step to 187C on the top step.  And only the top step (187C) didn't look grainy!

I've been cooking my filament to death, hence the blobby fine features and the strings everywhere on the hollow calibration pyramid.

The moral of the story is to not trust anything the 101Hero tells you: Verify every single thing.

I also increased the retract distance to the recommended 4.5 mm.  And increased the feed rate to 105% (though that may not be necessary).

I'm reprinting a couple items as I write this.  Will post photos when they complete (sometime tomorrow...).

I wish I could tell Cura to queue up some prints, and use the print carriage to shove a prior print to the edge of the bed.

  • BobC
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Re: Please help me find all that's wrong with my first print!
Reply #3
My XYZ Cube (image attached) has exactly the right dimensions, but the top needs more infill, more infill overlap, and more layers.


Re: Please help me find all that's wrong with my first print!
Reply #4
right i had most of these problems fixed them but now it wont extrude ANYTHING at all just do a dry print???

  • fedplast
  • [*][*]
Re: Please help me find all that's wrong with my first print!
Reply #5
My XYZ Cube (image attached) has exactly the right dimensions, but the top needs more infill, more infill overlap, and more layers.



BobC, I might be wrong, but I would not use the gold filament for testing or calibrating. that wire is loaded with either mica powders or other heavy pigment. regardless of the quality, it might affect it's thermal property. rheology and stuff...

  • BobC
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Re: Please help me find all that's wrong with my first print!
Reply #6
BobC, I might be wrong, but I would not use the gold filament for testing or calibrating. that wire is loaded with either mica powders or other heavy pigment. regardless of the quality, it might affect it's thermal property. rheology and stuff...
Well, I need to use this for several prints I want to make, so it needs to work, whatever it takes.

It may make my specific results less useful to others, but the general approach should still be useful, especially when/if I do get great looking prints with it.

Once those prints are done, I'll switch to my fluorescent orange filament and start over again.

  • BobC
  • [*][*]
Re: Please help me find all that's wrong with my first print!
Reply #7
The first image below are my three XYZ Cubes, with the first on the left and the newest on the right.  Only the last one has a complete top surface.  It also has the sharpest letters.

After that are phone shots of the settings.  If they're unreadable I'll do proper screen captures.

I'm now printing my first attempt at 0.10 mm layer thickness, another Star Trek TNG Communication Badge.  The gently rounded upper surface had distinct steps in the first print shown earlier in this thread, and I'm curious to see how much difference I'll see going from 0.18 to 0.10 makes.

It did take several tries to get it started: The bed leveling is much more fussy at 0.10.  Until I realized I could set the first layer as thick and as wide as I wanted.  Doh!

  • fedplast
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Re: Please help me find all that's wrong with my first print!
Reply #8
thanks,
r u using cura 2.5? my ihero101 looked a bit different... I'll copy your settings as I'm getting way too much stringing....

  • BobC
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Re: Please help me find all that's wrong with my first print!
Reply #9
thanks,
r u using cura 2.5? my ihero101 looked a bit different... I'll copy your settings as I'm getting way too much stringing....

Everything is for Cura 15.04.6.  I liked 2.6-beta, but I don't want to give up the Pronterface printer UI.  See this post.

I probably should get Octoprint up and running: I have a RasPi2 waiting for it.  That will probably make 2.6 better for me.

  • BobC
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Re: Please help me find all that's wrong with my first print!
Reply #10
More experiments here in my blog.  This time, I make a custom temperature calibration tower to try to find out how bad my extruder temperature reading really is.

  • BobC
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Re: Please help me find all that's wrong with my first print!
Reply #11
Made my printer more rigid!  See my blog post.

  • BobC
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Re: Please help me find all that's wrong with my first print!
Reply #12
I'm now getting good prints pretty much all the time.  I showed my latest 3D Benchy to friends having access to much more expensive FDM printers, and they've been very favorably impressed.

My last remaining noticeable problem is general "fuzziness" on the print and stringing across gaps, which I now suspect may be more of a filament issue (I've tried a wide range of temperatures and retraction distances).  But it has encouraged me to get much better at using my Xacto knife!

I've now done a few prints that required the full bed, and it is here that the tiny errors in the 101Hero Marlin firmware configuration can make themselves known through a slight "bowl" effect.  My best results have been obtained using lots of gluestick with a thin (normal) first print layer: The hot nozzle actually pushes the filament into the glue!

For smaller prints, blue tape is still easiest.

The "bowl" effect is reduced if the printer frame is made stiffer.  My US$5 solution was to cut three (roughly) 10"x7" pieces of acrylic to slide between each pair of pylons.

For most of my prints, going down to 0.10 mm layer thickness to obtain better detail doesn't really help all that much, given the 0.4 mm nozzle.  I'm finding that a 0.18 mm layer thickness provides a great trade-off between speed and detail.

Another observation (on my system) is that printing directly from Cura/Pronterface can fail for large prints.  If Cura says the print time will be over 2 hours, I always use the SD card.