troubleshooting [Bukobot 3D Printer Instructions & Docs]

This pages aims to help people solve some of the problems they might encounter.

Remember that there can be multiple possible causes for the same symptoms. If you are not fixing the right cause it will either not help or may make other problems worse.

If you have solved a problem which you think might be useful to others then please add it to this page.

===== Software =====

^ Symptom ^ Possible Causes ^ Suggested Remedies (for each cause) ^
| Print stops mid-way through | 1) The Azteeg Arduino controller boards (and especially the USB circuitry) are sensitive to electrical noise. Turning on/off other appliances, plugging/unplugging other equipment, or just bad mains noise can cause the USB connection to drop out. The Repetier-Host software (especially older versions) is not very good at recovering dropped USB connections (and if the Arduino has reset then there's nothing the host can do anyway). | Installing a mains EMI/RFI noise filter (e.g., used for computers) or a small Uninterruptable Power Supply (UPS) can help with electrical noise. |
| | 2) A "ground loop current" can cause the USB connection to drop out. This is mainly a problem with long USB cables or if the printer is not plugged into the same wall outlet as the computer. | Make sure your USB cable has a ferrite ring on the printer end of the cable (a small cylinder shaped object near the plug). Try to shorten the USB cable. Change the outlet where the printer is plugged in. Buy an inline USB Opto-isolator if you need longer cables. Buy a Raspberry Pi or wireless serial module to drive you printer (see instructions on wiki). |
| Bukobot does not respond to movement commands. Console in Repetier Host displays the message: "Printer stopped due to errors. Fix the error and use M999 to restart. (Temperature is reset. Set it after restarting)" | 1) Your controller has the dual firmware loaded but you only have a single extruder (the console indicates the number of configured extruders). |
| | 2) The thermistor is not connected properly. E.g., a wire has come out or making a poor connection. [This assumes that your firmware has the correct 100K EPCOS thermistor configured (which all of the stock Bukobot firmwares do). |
| Host cannot communicate with printer on Linux | Not all linux programs supports the default but non-standard 250000 baud rate used by Marlin (selected because this is an exact multiple of the 16MHz clock). | On Linux it is recommended that you change to 115200 if 250000 is not supported. Most people recommend 230400 is not used because there is up to 6% sampling time error due to high differences between 230400 baud and the 16MHz clock. |

===== Hot-ends, Extruders and Thermal Issues =====

^ Symptom ^ Possible Causes ^ Suggested Remedies (for each cause) ^
| Hot-end has trouble reaching desired temperature | 1) Power-supply is set to incorrect supply voltage (e.g. set to 220V for 115V area) | Set power supply to correct input voltage. |
|  | 2) Extruder fan is blowing onto hot end | Adjust fan or add thermal insulation (see below) |
|  | 3) Operating in a very cold environment | Add some thermal insulation around hot end. E.g., using ceramic tape, rectangles of silicon from oven molds/trays (see also: http://bukobot.com/hot-end-thermal-management). Can also increase power supply voltage to 13.5-14V instead of 12V (using the small trimpot adjustment on the power supply and a multimeter) to increase power dissipation of heater element. Could also build a cover around Bukobot or relocate. |
|  | 4) Poor connection in heater wiring. | If the supply voltage setting and airflow are all normal, then there may be a poor connection in the wiring. Ensure that the screw terminal connections are all solid. |
| Extruder slips on filament (clicking sound) | 1) Gummed up drive gear teeth | Clean drive gear teeth (e.g., with brush or a pointy piece of filament). |
|  | 2) Not enough extruder spring tension | Ensure the nut is done up all the way on the spring tensioner screw. Some particularly stiff and problematic filament types many benefit from adding a couple more washers to get a bit more compression. |
|  | 3) Hot-end is starting too close to print bed which is preventing the filament from extruding. | See print-related problems for remedies. |
|  | 4) Filament is thicker than configured filament diameter and extruder cannot extrude the extra plastic. | Reduce the configured diameter to match filament (requires reslice) or reduce flowrate (remember that flowrate is proportional to area so therefore should be set to (diameter configured/diameter actual) squared). This can also  be a problem on poorer quality filaments where there is a large degree of variation in the diameter from one point to the next (hence the recommendation to take a number of thickness measurements along the filament and average them). |
| Dark liquid is slowly leaking out from under PEEK (plastic) insulator on hot-end. | This is considered normal when extruding PLA (as long as it not leaking out too rapidly), i.e., cosmetic issue only. Turning up the hot-end up to 240C and running a meter or so of ABS filament through the extruder is believed to help seal any holes (ABS is not as runny as PLA and melts at a higher temperature). Note that the new Spitfire hot end is all-metal, and does not leak|
===== Motors and Movement =====

^ Symptom ^ Possible Causes ^ Suggested Remedies (for each cause) ^
| Motor moves in the wrong direction | 1) Motor connector is reversed. | Flip over motor connector. |
| After a reset the tool head does not move in a negative direction (using manual controls). | This is expected behaviour - negative moves are prevented until the axis has been homed. |

===== Print Related =====

^ Symptom ^ Possible Causes ^ Suggested Remedies (for each cause) ^
| First layer doesn't extrude properly | 1) Hot-end is starting too close to bed or bed is not level. | Go through pre-flight check to ensure that you can fit a piece of paper between head and bed with only slight resistance all around bed. |
| Extruded filament has gaps | 1) Filament drive gear is slipping. | See possible causes and remedies in Extruder problems section. |
| | 2) Filament has absorbed a lot of moisture from the air. Thus turns into steam in the nozzle and cause bubbles. Your can normally hear a small hissing or popping sound  if this is occurring. It is mainly a problem with ABS, PVA and nylon filaments. | You can usually dry the filament in an oven or similar before printing if necessary. However, store filaments which are liable to absorb moisture in a sealed bag (ideally with desiccant). Google for drying methods. |
| | 3) Dust/cardboard/other particles on the filament might be intermittently blocking the nozzle. | Fold a piece of tissue or paper towel around the filament and hold it in place near the spool with a binder clip & string (for example). This cleans the filament as it comes off the spool. |
| Some layers print fine but some have irregular height or not strongly bonded | 1) Too much resistance in pulling filament off spool causes X-carriage & hot-end to lift. | Install a filament feed tube (PTFE or LDPE plastic tube with 4-5mm internal diameter) or reduce resistance on filament spool (e.g., use bearings). |
| Print starts out fine but shifts to side after a certain height | 1) Motors are getting too hot and cause motor mounts to deform which changes tension in syncromesh cable. | Reduce stepper driver current by turning trimpot counter-clockwise (for SD82A/B stepper drivers). Reduce cable tension if too tight. |
|  | 2) Motor could be skipping steps during printing if motor driver stepper current is set too low (especially if this is mainly occurring at higher speeds). | Increase stepper driver current by turning trimpot clockwise (for SD82A/B stepper drivers). For SD82A/B stepper drivers the Vref test point should be set to 0.4V to give a stepper motor current of 1Amp (see Panucatt SD82A/B user guide). |
| Extruded filament sticks to hot-end during printing | 1) This can occur with very soft or poor quality PLA filament. | Most people recommend trying to print these types of filament very slowly and with thin layers (say 0.2 or lower). Some experimentation for optimal temperature is required and usually varies for each type of the filament. The best solution is to buy good quality filament (e.g., printbl.com) - 3D printing has enough challenges without adding problematic filament. |

Other

^ Symptom ^ Possible Causes ^ Suggested Remedies (for each cause) ^
| The controller board does not work if the USB cable is not plugged in. | The Azteeg controllers have a jumper which selects whether the Arduino and USB circuitry are powered from the USB host or from the onboard 5V regulator (INT position). On the Azteeg X3 controller, this jumper is located until the shield and so can be easy to miss. | Change 5V power jumper to INT position. |
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