Issue with MK3
Greeting,
I have had my MK3 for a little over 3.5 years. And I'm having trouble printing with it - I have tried lots of things to fix it.
I replace the belts, Extruder gears, the Hot end with EV3D original part, Nozzle twice since replacing the Hot end (I replaced the Hot end because the Thermistor wire broke off right at the sensor). I have a new Prusa powder coated PEI build plate. When I try to Calibrate the first layer, I can't get the filament to adhere to the table. I have tried a range of Z height settings and different nozzle and bed temperatures. It seems like the extruder is not pushing out enough material to make the line width wide enough to stick to the table (that's why I replaced the Extruder drive gears - purchased directly from Prusa). My next theory is it possible I have a partial broken wire somewhere that is causing the extruder or heat bed to register the wrong temperature or a broke wire that is causing the extruder motor to turn slower. I'm not getting any error messages on the machine. Please Advise.
Thanks, Shawn
RE: Issue with MK3
You said you've had it for 3.5 years, but what you left out is whether or not you have ever had it working properly during that time.
RE: Issue with MK3
Can an image of your post your first layer test or calibration?
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Chuck H
3D Printer Review Blog
RE: Issue with MK3
When you changed the nozzle 12, 24V is your power supply matching your nozzle?
RE: Issue with MK3
When I got the new nozzle it was for a 24V power supply which is what I have. I measured the resistance of the heater cartridge at 14.4 ohms which I understand to be for a 40watt heater. So the reason I replaced the whole hot end assembly was because it had lots of melted plastic stuck to it from a failed print and in the process of trying to remove the plastic I broke the lead wires off Thermistor. I measured the resistance of the heater cartridge in my original hot end at 15 ohms. My son has a different brand 3D printer with a EV6 24V hot end and his cartridge measured 21.2 ohms. I also measured the coil resistances on the extruder stepper motor at 7.2 ohms each; I have no Idea if this is correct - but the motor seems to be working and what are the chances that both coils would fail and end up at the same resistance value (very unlikely). When I try to do the first layer calibration it seems to push out enough filament to make the first about 20mm of extrusion line but after that the line gets really thin and doesn't stick to the bed. I have tried many different z offset values and tried different temps for the hot end and the bed and it doesn't fix the problem - I'm completely stumped on this. I think the next thing I will try is putting my original heater cartridge in and see if that helps.
RE: Issue with MK3
check E steps its so easy to change things and not reset your setting I thought my extruder motor was us but it turned out to be the E steps
RE: Issue with MK3
Have you checked that the extruder gear set/grub screw it tight against the motor shaft ? Doesnt matter if the extruder motor turns if the filament drive gears dont.
You have to be methodical when checking things. So if you want to check if your extruder can melt filament then preheat to your filament temperature. Open the extruder door so its not contacting the filament and manually feed filament through your hotend. If it flows out without too much resistance then you know the temp of the extruder is enough. If its difficult to push through then you know theres an issue with your hot end. Narrow the area it could be down.
If it extrudes easily then make sure the drive gears are tight and the tension is good and using the lcd command the extruder to extrude say 100mm of filament. If it does then you know your extruder is working. Take everything step by step. Dont change or check more than one thing at a time. If you change 3 things and it doesnt work you dont know which of the 3 it is (or even if it is ANY of the 3).