Alright, someone please help..

Discussion in 'Calibration, Help, and Troubleshooting' started by Jmenafra, Oct 7, 2016.

  1. Jmenafra

    Jmenafra Member

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    Alright, so I have a bigbox titan hybrid printer. I didn't buy it myself, but ended up building it and now am in the struggle of getting it to run and have any print consistency. Most problems I have run into I have troubleshot with success and used this forum as an aid. At the moment, I can't seem to figure out these problems:

    1) Temperature of left extruder reads plus 100C at room temperature. It will physically be cold to touch but read a high temperature.
    2) Back bowden extruder seems to have seized and spins the gear back and forth, even without filament in the tube. I have not yet dissembled it to check for any mechanical issues so that still needs to be troubleshot hands on.
    3) I consistently get "MAXTEMP" errors whenever any little thing happens to the printer. Found many threads about that problem but still couldn't seem to solve it.

    There are other small quirks that I have not worked out, but those are the major problems I'm trying to solve at the moment. Any help would be greatly appreciated, remember I'm still a beginner with all the jargon too.

    I've added the photo of all my wiring. It's a big more confusing due to two things. 1 being that I had z-axis issues which replacing the connector with 2 small black/red ones I had fixed. And 2 being some extra wires in the bottom right of the picture, those are to some print lights I hooked up. I'm also not sure which orientation the PT100 connectors go as the build manual has different connectors.

    Any feedback on any of these issues would be awesome guys.

    IMG_5388 (2).jpg IMG_5386 (2).jpg
     
    #1 Jmenafra, Oct 7, 2016
    Last edited: Oct 7, 2016
  2. Kanedias

    Kanedias Well-Known Member

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    There's a fault between the board, amplifier and pt100 cartridge which reads the temp. Try and isolate if it's the pt100 itself or the amplifier by swapping them and to see if the problem follows.
     
  3. Jmenafra

    Jmenafra Member

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    So swapping the connectors between the pt100s resulted in the high temp reading changing from extruder 2 to extruder 1. That means that the pt100 is the issue then correct?

    Also does the change in polarity impact the pt100s? The build manual shows a white and red connector, but mine is red and black. I assumed white was the hot end so matched red to red and white to black, but it works both ways.
     
  4. Kanedias

    Kanedias Well-Known Member

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    it just uses the change in resistance to calculate temperature so polarity doesn't matter as far as I know.

    Just make sure you confirm whether it's the pt100 itself or the amp so you know what you need to replace. if you can plug the 2 wire cable into either amp and it errors then yes it's the pt100. Which is good, it's the cheapest bit I think :D
     
  5. Jmenafra

    Jmenafra Member

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    For clarification, is the pt100 and amplifier not on the same board? I thought it was all combined on those single green circuit boards on the right side of the rumba? How would I be able to replace the pt100 and not the amplifier if so?

    Thanks for the clarity, as I said I didn't buy this so I'm learning as I go
     
  6. Jmenafra

    Jmenafra Member

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    Oh so the green boards are just the amplifiers, and the rods which go into the extruder setups are the pt100 resistors themselves?
     
  7. Kanedias

    Kanedias Well-Known Member

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    The pt100 is the cylinder that goes in the heater block. It connects to the amp board which is the little green one next to the rumba. It's possible the cylinder bit (pt100), or its wiring, may be the fault and the amps are both fine. If you swap the connectors going From the hot end to the amps then
    If the error moves to the other hot end the pt100 is suspect.
    If it remains on the original hot end the amp is suspect.
     
  8. Jmenafra

    Jmenafra Member

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    Right so swapping the pt100 leads between the two amps did carry the error over to the other extruder, therefore the resistor itself seems to be the problem. If they aren't too expensive I'll just replace them both. Maybe I tightened the grub screws holding them in place too much? Also could just be faulty wiring. I wonder if that is what gives periodic MAXTEMP errors..

    I appreciate the help, but have a few more questions if you don't mind giving your opinion.

    1) When a print starts I feel the extruders are slightly too high. The filament has a good 1.7(ish) mm before it reaches the bed. I have restored failsafe and recalibrated a good 5 times now. Can't figure out what I'm doing wrong. I got it where it seemed lower once, and then by accident when scrolling through menus quick I hit the failsafe and haven't been able to get it back to that again. How far should the nozzles be off the bed?

    2) I use Cura as a slicer (its free is the main reason) and I can't tell figure out how to tell it what extruder to use. So some gcode files heat up extruder 1, while others extruder 2, and I seem to have no control over it. I googled and it seems I have to edit the gcode itself, but have no idea how to do that.

    3) Cura itself didn't have the bigbox as a selectable printer, so I picked a random one. It has a smaller print bed and therefore I can't slice an object which exceeds that print space, when in actuality it would fit fine on my print bed. Any ideas?
     
  9. Dr Jeep

    Dr Jeep Well-Known Member

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    Right if you are new to this then it's not a great situation to be starting with a slicer that doesn't have a correct profile :/ There is a lot more to get right than just the bed size, loads of variables. S3D is a good new option because the profiles are quite well developed but I appreciate it isn't cheap.

    There was a commitment from the E3D team to support more slicers but I honestly haven't seen much in that respect, it might be worth asking in a new post if anyone has a good profile for Repitier/Cura etc they have developed themselves to get you started. Debugging a new printer whilst trying to build a profile from scratch will NOT be fun.

    The other way you could do it is that the S3D profile is readable in notepad, it's not going to be easy as some of the configuration items have different names but you could read though that and configure a new cura profile step by step.

    I think dual extruder has variable support in different slicers.

    In terms of nozzle height it should be almost no perceptible gap at the start of a print, this is a different process for the dual to the one I use for my single, but ultimately it sounds like your extruder offset settings are wrong. When the printer controls think Z is 0mm then it should be no more than a paper thickness from the bed, the actual height your print starts is defined in the slicer but is usually a bit less than whatever layer height you selected, so we should be talking in the order of sub mm here.
     
  10. Jmenafra

    Jmenafra Member

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    Thanks Dr Jeep, I'll definitely post a thread and try to find an already developed slicer profile out there.

    I'll have to redo the calibration as well, I follow each step so I'm not sure where I'm going wrong. I'll probably have my roommate try to follow the calibration, sometimes it's just the littlest thing you miss and don't even notice so a second pair of eyes is always helpful.

    Kanedias, and Dr Jeep too, going back to the high extruder temp, I've been thinking more about it, and is there a thermocouple that actually reads the temperature? Or is it just calculated from the voltage/resistance supplied to the pt100? The way I'm thinking about it is that this is a closed loop PID (at least I'm pretty sure it is) so if the feedback temperature is read from a thermocouple than that could be my faulty hardware, and not the resistor or amplifier itself. Now if it's the amplifier that somehow uses the resistance or voltage difference to calculate a temperature and send that to the rumba, than of course the problem resides there. I'm just not trying to replace parts until I know a true root cause here. The resistors themselves seem pretty cheap (you have to buy a few in a pack anyway) so I might as well just replace them and see if that fixes it I guess..

    Ideally if I can fix this faulty temperature problem and find a good slicer profile, I'll be able to start printing consistently! The bowden motor issues I'll have to work out another day, still not sure what happened there. Baby steps, baby steps.
     
  11. Dr Jeep

    Dr Jeep Well-Known Member

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    I think you are confused about the function of the PT100. The PT100 performs the function of the thermistor (but PT100's work at millivolts so hence the function of the amp).This forms half of the closed loop PID.

    You can convert to standard thermistors but I wouldn't recommend it (and you have the wrong heater block)
     
  12. Jmenafra

    Jmenafra Member

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    That definitely clears things up, so it changes in resistance as the heat block increases in temperature and that is used for feedback for the PID loop. I think I'm going to replace the PT100s in extruder 2 (the direct drive hot end for the hybrid model) and hopefully that fixes this issue. Is it a 100ohm PT100? I checked out on amazon but there seems to be different resistances and lengths so I want to make sure I get the exact ones supplied originally.
     
  13. Jmenafra

    Jmenafra Member

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    Shes working!! Halle - F***ing - lujah shes actually printing. Thanks for all the guy guys!!

    I replaced both PT100s and that fixed the temperature issues. Seems I tightened the grub screws holding them in too much, cracking the casing on one, denting the other.

    I also re-calibrated the entire set up again and found in the gcode that it was starting Z0 at 2.7mm. Wayy too high. Changed it to 0.5mm and it started off printing the skirt at a good height.

    First Real Print.jpg
     
    mike01hu and PsyVision like this.
  14. Kanedias

    Kanedias Well-Known Member

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    Well done. You've certainly given yourself a challenge for your first printing experience so kudos.

    If you want to check your Z gap you can run the autohome sequence then use the prepare menu to move axis and move your Z to 0. The extruder should now be almostbutnotquite touching the bed. Knowing this you can fine tune the gap by changing the Z offset under the control menu.

    Some filaments might need a little more or less smooshing into the bed. It can also depend on your layer height. I've found if I print at .1mm I need a slightly smaller z gap.
     
  15. Jean VISCONTE

    Jean VISCONTE Member

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    Check for bad contact between the head sensor and th PT100 amp. I have sometimes same phenomenon which end up with a MAXTEMP error. I cure this by a weekly spray of contact cleaning product. Bad quality of contact plus possible pollution from printing environment (fumes, adhesive sprays... ) is behind this. Solution (not implemented yet) would be to replace contacts by a simple solder which would eliminate all this, at the cost of less modular head assembly.
     

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