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Answered I have all the problems. Anyone have solutions?

Discussion in 'Troubleshooting' started by NJB, Apr 20, 2018.

  1. WheresWaldo

    WheresWaldo Volunteer ( ͠° ͟ʖ ͡°)
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    Make sure that the switches for Z axis, there are two, both work and are both connected to the outermost pair of spade lugs.The basic design of the printer was that the wobble should be okay, in most cases. If your lead screws are seriously bent then it can be a problem. If those lead screws are overly contrained it can lead to print problems and in severe cases stepper failure. That is why this design, which is a adaptation of an early 3D printer open source design, did not constrain the top of the Z axis lead screws.
     
    #21 WheresWaldo, May 26, 2018
    Last edited: May 26, 2018
    mark tomlinson likes this.
  2. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    Sure sounds like a Z switch misbehaving.
     
  3. NJB

    NJB New Member

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    I fixed the thing where I couldn't get the Z axis to go to zero. The x carriage wasn't quite level and it was randomly bouncing off of the switch on one side.

    I've run a few Z resonance tests. Here's the stock acceleration with the brackets at the top of the lead screws:
    Photo May 26, 8 56 08 PM.jpg

    Here's with reduced acceleration and no brackets on the lead screws:
    Photo May 26, 11 45 09 PM.jpg

    I'd say neither is very good. Any suggestions on how to fix this?
     
  4. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    If this is an R1 then some minor ribbing is just part of the deal on the taller Z objects*.
    The solution to that was the Z axis upgrade for the R1 which effectively made it an R1+.

    If this is an R1+ then that is still some mechanical resonance and can be adjusted away (unless a Z rod bracket is loose or something mechanical is still getting in the way).

    A closer up picture of the effect would be helpful.



    *search the forums for Z ribbing. There are a lot of threads for the R1 on this. There are some minor things you can do to improve it without replacing the Z rods for leadscrews, but that is the only complete solution.
     
  5. WheresWaldo

    WheresWaldo Volunteer ( ͠° ͟ʖ ͡°)
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    It looks like an R1+PLUS, I would tweak the acceleration setting even further downward, also make sure that your X and Y axis acceleration numbers are in line, Z should technically be the slowest, but X and Y on this style of printer is critical to having vertical sections of your print upright.
     
  6. NJB

    NJB New Member

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    Yes, it's an R1+. I see that this design is supposed to tolerate some wobble of the lead screws. How much is too much? I tend to think the Z ribbing is entirely a result of the lead screw wobble, given that it's always the same frequency.

    Here's the best close-up I could get.
    Photo May 27, 2 49 40 PM.jpg

    Here's a dropbox link to an animated GIF of the z lead screw wobble.
    https://www.dropbox.com/s/i1qv8d4co5q0ya1/wobble.gif?dl=0
    The forum wouldn't let me upload it. It says "Max 512 MB," but I can't upload a 3.8 MB GIF...

    Current settings for acceleration:
    Max acceleration [ mm/s^2] X: 4000, Y:4000, Z:100, E:2000
    Acceleration: 1300

    What's a good value for acceleration?
     
  7. WheresWaldo

    WheresWaldo Volunteer ( ͠° ͟ʖ ͡°)
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    About 800 or less for acceleration. This particular printer design simply can't take much more than that. It is cheap and easy to make with a large build area, which is probably why Robo chose to use it. Max acceleration should probably be in the 1200 to 1500 range for print moves, travel moves can be faster.

    In the community firmware the numbers are as follows:
    1. DEFAULT_MAX_ACCELERATION { 900, 900, 300, 10000 }
    2. DEFAULT_ACCELERATION 600
    3. DEFAULT_TRAVEL_ACCELERATION 3000
    Unfortunately this is simply not a very rigid printer design, Robo left all the Marlin default settings for these things in their firmware. They are about as far off from reality as you can get. Also a quick look at the visual Print Quality Troubleshooting Guide that is published by Simplify3D can give you some other general suggestions. You do not need to use Simplify3D to apply the suggestions in that guide.
     
    #27 WheresWaldo, May 27, 2018
    Last edited: May 27, 2018
  8. NJB

    NJB New Member

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    Printed another Z test with the acceleration settings shown below. No difference. Screen Shot 2018-05-27 at 3.33.27 PM.png
     
  9. WheresWaldo

    WheresWaldo Volunteer ( ͠° ͟ʖ ͡°)
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    Did you look to see if there were any suggestions in the Simplify3D Guide?
     
  10. NJB

    NJB New Member

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    Yes, I've been using that guide throughout my 3D printing misadventures. For the Z ringing it lists printing too fast, acceleration and mechanical issues. I'm pretty convinced my problem is mechanical. The Z wobble on the right side lead screw is probably the cause. My friend bought this printer a couple years ago and right away noticed that one of the lead screws was bent. He called Robo3D and got the canned response that some amount of wobble is OK and won't affect the print quality. I understand the logic, but this is clearly affecting print quality. My friend eventually got fed up with the printer because he couldn't get it do print anything well. He recently lent it to me, and I've been similarly disappointed. Frustrating. I think I'm just going to hard pin the lead screws and if the motors burn up, I'll just buy him a Prusa to replace it.
     
  11. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    It may not be the wobble itself at all causing the issues. Both of my R1 units have significant wobble (one is a + the other not) and it doesn't affect the build quality at all. There is likely something else in play. The mounts for the smooth rods would be my suspect. Make sure they are not cracked/broken/.loose on the base where they mount because if they are then the threaded rod (or leadscrews on the R1+) can't significantly affect the crossbar when it wobbles.
     
  12. NJB

    NJB New Member

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    I checked the screws that hold the smooth rods to the base plate and the ones that hold the plate to the outer case. They didn't seem loose, but I have them each a 1/4 to 1/2 turn anyway. Haven't printed a Z column test, but I suppose I should. I'm sort of moving on to the next problem, which there being gaps in my prints. Picture below. Is this possibly due to the filament slipping in the extruder? I've seen it over a range of temperatures. It's strange that it didn't do this on the Z column. It does it a lot on "Benchy." I wonder if it's related to retraction. I was using a retraction distance of 3mm, but I increased it to 4mm to try to get rid of my stringing problems. It didn't work. I haven't been able to solve the stringing problem with retraction distance/speed or temperature. Any thoughts?

    Photo May 30, 4 47 26 PM.jpg
     
  13. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    Well, regardless of why that is an extrusion issue. Calibrate the extruder first to make sure it is fundamentally working correctly. Then gaps in extrusion usually become filament related.
     
  14. NJB

    NJB New Member

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    I calibrated the extruder as you suggested earlier in the thread. I changed the steps/mm by about 4%. Didn't produce a noticeable difference, but it's good to have that dialed in.
     
  15. NJB

    NJB New Member

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    Update... A friend of mine had me try Simplify3D and all of a sudden I could print parts without all the nasty gaps and stringing. So that was a huge success. I'm about halfway though printing this jet engine model: https://www.thingiverse.com/thing:1327093.

    Today I went to continue printing more parts and discovered that the bed wouldn't heat up. I opened up the case to check the connections and found a bad solder joint on the terminal block that connects the bed element to the ramps board. The terminal block is partially melted and blackened. I ordered some new terminal blocks on Amazon to fix it. This printer hasn't burned my house down yet, but it sure is trying.
    IMG_5296.jpg
     

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  16. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    There are other threads on this and it is a known issue that can happen with RAMPS boards. Make sure the new connector has a tight connection to the wires. Loose connections = higher resistance and more heat generated with 11 amps running through it.
     
  17. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    P.S. I would just replace the RAMPS board, but you can probably clean that up and replace the connectors if you really want to.
     
  18. NJB

    NJB New Member

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    I replaced all the terminal connectors on that side of the board. The bed heater works now. Unfortunately I have a new problem. After it prints a few rings of the skirt, it starts veering off course in the X direction and crashes into the end (the far end, not the one with the limit switch). The axis Y keeps working normally, but a short while into the print, the X axis only moves in the + direction. I took pictures of the RAMPS board and labeled all the wires before I disconnected it, and I’m pretty confident the stepper motors were at least connected in the right orientation. Any idea what might cause that? The picture shows what it printed. It’s supposed to just be a rectangle.

    F8B308A9-2FFC-4DF6-A9F2-4CBB8E939B53.jpeg
     
  19. WheresWaldo

    WheresWaldo Volunteer ( ͠° ͟ʖ ͡°)
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    Usually the X moving on every layer in one direction only may indicate a bad limit switch. Double check that the switch is 1. wired correctly, 2. working.
     
  20. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    Other than the limit switch it has to be either the stepper dropping steps or the stepper driver not sending them.
    Switch is more likely :)
     

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