Getting ready to just sell this thing

Discussion in 'Calibration, Help, and Troubleshooting' started by wfredette, Apr 29, 2016.

  1. wfredette

    wfredette Well-Known Member

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    I know people are having consistent success with their BigBoxes. I'm just not one of them. I thought my delta was persnicketty, but at least when I got it dialed in, it stayed that way and performed consistently. The BigBox, on the other hand, I have zero confidence in. It will print reasonably well for one job, then I'll turn it off, turn it back on again, and I have NO idea what it will do.

    My biggest problems are with the distance between the nozzle and the bed, and the movement of the bed (so, I guess, homing, Z offset and auto leveling). I will home it, autolevel it, store the memory and get a decent (though by no means really good) print. Then I'll power down, come back later - often with the exact same gcode - and the printer might start printing 3 or 4 mm above the glass. Or it might, as it has been doing this evening, refuse to lower the bed during the intial dock/purge, so the nozzles hit the edge of the glass when leaving the dock, and scrape their way agonizingly to the middle of the bed where the extruder starts skipping like mad as it tries in vain to squeeze out some filament through a nozzle that is pressed firmly to the glass. The dragging across the plate also, of course, torques the hotends all around, and readjusting them with the grub screws is imprecise at best and nearly impossible at worst.

    I know from experience that this is not a set it and forget it venture, but I would really welcome suggestions for at least getting to the point where I can trust the thing not to try to destroy itself when I turn it on. It's a BB Dual, with original firmware. Should I update the firmware? Change something in Simplify3D? Make a BigBox shaped hole in my wall?
     
  2. Richard Barbosa

    Richard Barbosa Well-Known Member

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    It's hard to say without actually looking at it and checking it for myself but I would be leaning towards maybe having a bad IR Sensor or missing something in the commissioning process of the dual version. The manual kind of leads you one way and then the other way because of all the different BigBox versions and the different commissioning processes for each.
     
  3. wfredette

    wfredette Well-Known Member

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    Yep. I agree about the commissioning instructions. The thing that's killing me is how unpredictable it is from one power-up to the next. I can get some decent prints and then the machine will fail miserably, even on the same gcode that it had just printed successfully. I see the IR sensor flashing, so I assume it is working. I use hairspray on the bed, but that hasn't seemed to have had a consistent deleterious effect.

    The most recent problem is that the bed no longer lowers as the print head docks and purges, as it had on every print that I've done before today. So now, when the bed leaves the dock, the nozzles hit the edge of the bed. It's like flipping a coin when I turn the thing on as to whether or not it will perform correctly.

    I have a Raspberry Pi running Octoprint connected to the machine - basically so that I could use the camera. I will try taking that off, because I have noticed some differences in homing and offsets if I do them before the "OctoPrint Connected" message appears on the LCD sometimes.
     
  4. Richard Barbosa

    Richard Barbosa Well-Known Member

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    I have the exact same set up with no problems with octo,s3d or the dual. I just did a dual line print calibration that came out pretty good. The only thing is I co a combination of BigBox commissioning and my own separate adjustments especially a trick for exact centering 150/100 on each of the heads as well as during dual printing. Maybe if u made some time on video hangouts and let me see what you are doing maybe we can commission it together.
     
  5. Henry feldman

    Henry feldman Well-Known Member

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    Try changing to @Alex9779 's firmware that allows manual bed leveling, which is sooooo much more predictable...
     
  6. Kick2box

    Kick2box Well-Known Member

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    Always wait for that, because the Rumba will reset before and homing before is useless. Maybe the reason?
     
  7. Falc.be

    Falc.be Well-Known Member

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    What are you trying to print ? Benchy from the SD is bigbox pro only, will not work on dual.

    What profile are you using in S3D ? Make sure you have the dual profile.

    IR sensor loose ?
     
  8. Rob Heinzonly

    Rob Heinzonly Well-Known Member

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    The Benchy will print on Dual, I did it myself a couple of times.
     
  9. Ray

    Ray Well-Known Member

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    If you have the z axis dialed in properly then the nozzles shouldn't hit the bed I would have thought except for the following reasons (just me guessing):
    • IR sensor not working correctly
    • Firmware issue (however if you are using the standard firmware I am not sure that should be the issue)
    • Z axis sticking or one/both z axis steppers out of sync
    For the last point about z axis sticking, you mentioned you have never been very impressed by the prints, have you had z banding in the prints, could the z axis not be moving freely and therefore you are getting height issues?
     
  10. Old_Tafr

    Old_Tafr Well-Known Member

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    I like many I suspect have a printer that simply works, dual, Pi with OctoPrint, Firmware as it came out of the box. I did have some oddities such as a virtually perfect benchy print and then others (not benchy) with "Thermal Runaway" but apart from fans too high I put that down to benchy being a preconfigured job and subsequent prints being my early attempts with s3d and getting used to different temperatures with different makes and types of filament (and the "default" temps in OctoPrint and s3d). I also tend to print with both raft and support ticked in s3d which seems to help with the first layers sticking.

    As you have inconsistencies between one power on and the next then (obviously) something changes. The changes seem to be between where the nozzles are in relation to the bed.

    There is a set sequence when the printer homes/when you raise the bed. i.e. the IR sensor triggers. So on the basis of doing something simple first and getting back to a known state and then working from there maybe some checks and checks against known working printers. Maybe someone has a video of the bed moving upwards and the IR triggering (from memory the bed raises the nozzle almost touches the bed, the bed drops and then raises a little) so you can compare that with what yours does? This sequence is obviously different if you just raise the bed toward the IR sensor or if you "home" but both are set sequences with distances set by the calibration/commissioning. A handy switch on the power connection is good to stop the printer if the nozzles hit the bed.

    This is assuming lots of things including the wiring to all end stops, IR sensor etc. is good and not intermittent, and the IR sensor isn't loose mechanically.

    One thing that does occur to me is that using hair spray on the bed, maybe that gets on the IR sensor itself (not easy to see with the particles from the spray blowing about) and on the bed immediately below the sensor, both of which could cause intermittent results. Maybe clean the bed, not use anything but a raft for PLA and kapton tape for ABS so the area around the IR sensor is clean and uncontaminated.

    Redoing the commissioning including the piece of belt under the IR sensor bit and the bed levelling will not do any harm once you have the bed and sensor sorted. Resetting the Rumba EEPROM to factory default (restore failsafe) is probably a good idea too before going back through commissioning.
     
  11. wfredette

    wfredette Well-Known Member

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    Thanks, everyone. I guess I'll take a breath and do the commissioning process yet again. @Old_Tafr, the printer does go through the start sequence as you described above - just not with the same result each time. And, yesterday, it started that new misbehavior of not lowering the bed a bit when the head travels to the dock to purge at the beginning of a print. I've kept the area of the bed that the sensor "sees" clear of hairspray, but it's certainly possible that that's messing it up.

    @Ray, I have had some artifacts on the z axis of many (though not all) prints. It's not really banding, but I guess it could be attributable to inconsistent z motion. It seems to move pretty smoothly, but I know others have had bearing problems.

    I'm sure there is probably a cumulative effect of more than one small problem here. It's just getting frustrating to see others' good results and to compare them with the mediocrity and hassle of my machine.
     
  12. Old_Tafr

    Old_Tafr Well-Known Member

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    So if the start sequence is not the same each time something is broke or worse intermittent. If this isn't right and the printer does not know the correct Z height then it's pot luck after that.

    Although commissioning may help, e.g. if the IR sensor gets it right at that specific moment, there is no guarantee that when you come to print it will get it right that time. So the commissioning may be right but just luck if a print works.

    I have just run Auto Home to see what happens....... I didn't see the red flash as the bed moves upward so it must be the light conditions, but I'm sure it is possible to see this. I will try again with the blind closed. There are two flashes (highly technical this bit !! :) ) first when the bed rises (I deliberately lowered it) at which point the bed drops a little then when the bed rises again (another flash) before the nozzle moves to the home position a little back and right.

    For this to be consistent, assuming the firmware wiring etc are ok the two end stops must work as the x-carriage moves fully left and towards you and it then moves to "home" and the IR sensor must be working. If you get the home sequence hitting the X and Y endstops then that is two things eliminated.

    Testing the repeatability would seem to be key here in what happens when the bed rises toward the nozzles i.e. the first flash, the bed dropping a few mm, then bed rising a few mm, then moving to home..a little right and back.

    Tedious as it may be, repeating this over and over again, dropping the bed first then auto-homing should help see if it is repeatable. Lowering the IR sensor may avoid a few head crashes but also ruin your calibration !

    If this auto-homing works over and over again i.e. with no input from Octoprint or s3d then move on to a test with one of them. If the problem happens when you print it should in theory be repeatable (using the same unchanged file each time) and related to some part of the gcode, unless it's a bug in s3d or firmware related to the commands used.
     
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  13. Dr Jeep

    Dr Jeep Well-Known Member

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    What is the store memory step you are doing after autolevel ? I don't do that, the only store memory I did was after initial calibration of the Z height and then after tuning the PID, If you power off the printer then regardless of what you store in memory it won't know where home is until it does another autolevel because steppers use relative positioning not absolute. Personally I have just put a G28 in my slicer start code so it autolevel's before each print and I am confused as to why that isn't the default in the supplied profile.

    Though I'm not sure hairspray is going to result in very consistent behaviour with that IR sensor, if the coating isn't 100% consistent then you might find it levels off intermittently either from the top side of the glass or the bottom. So far I have only printed on bare glass on my BB so this is just a theory.

    I think if you need to use hairspray then it might be better to put down something like kapton tape first and then hairspray over that...the kapton will bring the levelling up to the top layer of the glass even when the coating of hairspray is too thin to trigger the sensor.

    Though that bed scraping problem needs to be fixed first or you are going to be replacing a lot of tape :) Is the behaviour of the dual different for homing ? On the Pro after the commissioning phase and during an auto-home the printer ends up parking itself somewhere less than 5mm from Z 0.00 (depending on the results of the calibration you do in commissioning...mine ended up at 1.6mm) then the dock and purge happens with the bed at that height, so unless the bed is way out of true there is no chance of the nozzle contacting.

    To be more clear...my printer never goes to 0.00 in the course of normal operation, the closest it gets is 0.18 or whatever the first layer height is....this is different behaviour to my old microswitch Z home printer which actually set home at 0.00 and it took me a few moments to get my head around what was going on during the setting of the Z height in that commissioning phase.
     
  14. Pierce

    Pierce Well-Known Member

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    I had the same random bed level rubbish, sometimes printing 5mm above bed, I flashed the latest firmware (the one that fixed that annoying beep) and then started using the experimental profile from Greg on the forums and most of those issues have gone. The bed is now level and the printer remembers this and the print quality has improved greatly :)

    I always find there are moments when you want to scream at these printers, just come and post on the forum and we will come up with as many ideas as possible to help you get to the bottom of it :) that's what I do at least!
     
  15. wfredette

    wfredette Well-Known Member

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    Thanks again, everyone. I took a day off from messing with the printer to clean out my basement and attic (I know how to have a good time). Once I get the part of my basement rearranged that houses the printers, I'll get back at it.

    In reading through one of the firmware threads, though, I found this interesting tidbit from @Steven Burns: "It does not drag. It actually resets to 4 mm after each point and you use the knob to Move the head back down to touch the paper."

    He was replying to another member, who, in discussing mesh leveling, said that the thought of the nozzles scraping across the glass during the bed leveling process was unsettling. Thing is, that's always been the behavior on my printer. The LCD does show "4 mm" between leveling points, but the nozzles just get dragged across the glass from point to point and I have to lower the bed using the knob and then bring it back up to where I want it for each point. So, maybe that's a clue to my problem.

    I will try updating to the latest firmware, if I can divine which flavor I need. I see @Alex9779 mentioning several release candidates, and problems with the most recent. I guess I'll go to his github and poke around a bit...
     
  16. wfredette

    wfredette Well-Known Member

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    @Dr Jeep, the store memory step is included in the bed leveling procedure for the dual - I think. The commissioning steps in the Wiki are all interleaved in an annoying and confusing manner. But as I read them, after you run the print head through the 9 positions for the bed leveling, you are instructed: "From the Control menu select Store memory." So, I've been doing that each time I level the bed. I think, ideally, you only have to do that process once, but since I've been having so much inconsistency with where the nozzles wind up in relation to the glass, I've had to do it many times.

    I did think about the hairspray affecting the IR sensor, so I make sure there isn't any in the area that the IR sensor uses when auto-homing, but I'll clean the bed completely, and see if that helps.
     
  17. Henry feldman

    Henry feldman Well-Known Member

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    SO bed level is only for the current run (until you autohome or reboot the printer). You need to (bad UX choice) after bed leveling go to control->store memory of the bed level is lost. I can't think of a use case when you want to bed level and NOT store it, but that is the design...
     
  18. Steven Burns

    Steven Burns Well-Known Member

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    I still like the mesh leveling that I implemented a while ago. Since the change I have not had to level the bed at all although I think I will manually tram the bed to make it as parallel as possible and then re-mesh level it again.

    The issue appears to be that some of the sensors pick up the white Nd black in the PCB and interpret them as different heights. One print works well and the next sees a slightly different spot and the sensor trips too soon or too late.

    Also, you do not need "new" firmware to make the change. I did mine on RC3 and have not upgraded to a newer version yet. This will change when I get my pro Titan installed and have no choice except to uograde.
     
  19. wfredette

    wfredette Well-Known Member

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    Hi, @Steven Burns. Can you tell me more about the mesh leveling, or point me to a thread about it. Is it different from the 9 point leveling that I'm currently using with my dual?
     
  20. Henry feldman

    Henry feldman Well-Known Member

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    that is mesh leveling... the mesh is established at 9 points (vertex)
     

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