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3D printer repair problem

Posted by igor449 
3D printer repair problem
August 12, 2018 01:39PM
Hello readers!
I'm a 17 years old student and I'm doing a school project of how to repair 3D printers and I'm trying repairing a Clone of the Prusa i3, the Single Frame.
After have done some adjustments in the printer and done some structure repairs but now I have a problem with the printing proces.
The problem is that when I try to print, the filament doesn't go down because is "not enoght melted" and the extruder can't pulls it out from the nozzle. So it changed all the hotend and the hobbed but the problem stills there.
I thing that the cause of this problem is the filament, because I'm using ABS of 3mm and is not a good cuality one but I don't know which filament use instead.
How can I fix this problem?

Edited 3 time(s). Last edit at 08/12/2018 03:34PM by igor449.
Re: 3D printer repair problem
August 12, 2018 04:17PM
I think you use pla tempertures on abs filament. Either use the proper temperature or use pla. Also check the pid calibration of the hotend.

Kind regards

NFAN CoreXY printer:
Re: 3D printer repair problem
August 12, 2018 04:49PM
Thaks Imqqmi fot the reply,
I heat it from 200ºC (393ºF) to 260ºC (500ºF), and as I see it's ok for ABS so I did a litttle experiment:
I tried to use a 12v 7Ah battery to power the hotend and the problem still there, but the Marlin marked 130ºC (266ºF) when it was more than 200ºC, because it was juts melting, so I will have to revise that, but that's a minor problem.
I've borrowed a bq 1,75mm PLA filament, it melted well but the printer pipe is 3mm so it is too thin to go out from the nozzle.
So as I can see is the filament, but what can I do? Should I change the pipe or buy another filament?
Re: 3D printer repair problem
August 12, 2018 09:49PM
If your printer reads 130 but the actual temperature (how did you measure it?) is 200, then that's a really big problem and you should sort that out first. Check your thermistor table in firmware matches the actual thermistor you're using.
Re: 3D printer repair problem
August 13, 2018 06:47AM
Thanks Trakyan fot the reply.
I just suposed that was more than 200 because both PLA and ABS melt at those temperatures.
I don't know wich thermistor I'm using, so I used a multimeter to check the resistence that the thermistor gives at certain temperatures, trying with ice, cold water, ambient temperature and hot water to check if it's a problem with the Marlin or with the hotend, and the conclusion is that is the hotend, because the I see that the termistor is right, but not when I put it in the hole of the hotend.
I attached an excell with the graphics in Kelvin degrees and Ceslius degrees.
open | download - Thermistor.xlsx (18.8 KB)
Re: 3D printer repair problem
August 13, 2018 09:58AM
imqqmi, of what you have said about PID, I checked with PID autotune and now it's working as I would at first.
I used the comand "M303 E0 S240 C10" (at Poterface) to run PID autotune, I waited to reach at least 200ºC and the ABS filament melts perfectly, so probably it was all ok but the hotend can transmit enought heat to the nozzle and so the ABS doesn't melt. So now it's just change the PID values or run PID autotune another time and that will be enought.
Re: 3D printer repair problem
August 23, 2018 12:57AM
Personally I wouldnt be running pid's while I had filament in...especially abs...I'm guessing you'd mess things up though maybe not if it isnt reaching temp, how can it do the PID if it doesnt get to the right temp, also do you have ptfe in your throat or not?
Re: 3D printer repair problem
August 23, 2018 01:30AM
I am guessing that your problem is that you use 3mm filament in 1.75mm extruder. If this is the case you need to find 1.75 mm filament. [Did not read that you have tried this option already.] may be some components of the extruder like heatbreak or nozzle are 1.75mm.

Edited 1 time(s). Last edit at 08/23/2018 01:32AM by piper3d.
Re: 3D printer repair problem
August 25, 2018 08:20AM
I changed the values of the PID both the bed and the hotend, so now the hotend overheats but I prefer it because I'm using ABS of 3mm, so it doesn't underheat while I'm printing anything. But the bed is a bit crappy so it's quite difficult to reach at least 80ºC, but at least it prints.
So, my problem was solved correctly and now the printer prints almost perfectly.
Thank you very much!
Re: 3D printer repair problem
August 25, 2018 04:42PM
If temperature swings are a problem, try some insulation. That should reduce the rate of change, so your heaters might be able to keep up. Polystyrene or a couple of layers of cardboard underneath should help the heated bed. Or maybe you need a better power supply, especially if the heated bed is large. A 7Ah battery might last less than an hour. Also check the wires and connectors, especially to the heated bed; if the wires are undersized or the connections are poor, they will heat up and less energy will get to the heater.

Remember to re-run the PID tune after any changes.
Re: 3D printer repair problem
August 26, 2018 03:37AM
isn't there something better than a flammable material for the heat spreader/insulator.
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