Bad stepper driver

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gfeliksdal
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Re: Bad stepper driver

Post by gfeliksdal »

Hi Lioric, if you place the low current stepper driver on the z-axis and the z stepper driver on the extruderp position, you are good to go. The z-axis motor requires the least amount of power.

Lioric
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Post by Lioric »

Good call!

That did the trick, I swapped the stepper drivers and it is printing all day, wrenches, nuts and bolts, bearings and whatever can be used as a test from thingiverse. Simply amazing

I had to modify the firmware to take into account the difference between drivers (1/8 steps) but after that its printing like there is no tomorrow ;)

Of course I'm only printing on Draft Quality so the printings are a little (or a lot) "rough" but it only can get better (and even better with the correct stepper driver)

Wish the camera of the mobile phone were working so I can post pictures of it, I suppose I will use any of the web cameras of the other portable devices

The hot end is driving me crazy, it clogs every five minutes and I had to disassemble several times (I'm a little worried disassembling that many times might have modified the tolerances of the x rail). Every pause (even a few seconds) results in a clogged hot end. Retracting even at a high speed results in the same

Kjetilei
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Location: Stavanger, Norway

Post by Kjetilei »

Lioric: Good to see that you got the printer going :)

- What filament do you use?
- What temperature do you use?

I have thought about adding a 4-pin connector to the hot end for easy disassembling. I have readied a set of connectors used for charging 3S LIPO batteries for R/C models but not had the time to do the mod yet.

Guillaume: This seems similar to the problems I have faced both in the beginning and now.
- What has your experiences been?
- What about feedback from other users?
- Do you think it could be an idea to boost the stepper power a tiny bit?

Lioric
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Post by Lioric »

Im using white PLA from repraper (http://www.repraper,com), really nice filament (very consistent diameter), Im testing using 185C but it seems that it can go a little lower temp

After measurement of the backlash, the printer currently has 0.15 in X and 0.12 in Y. Using those values in SFACT is printing circles and hole perimeters a lot better

For the extruder clogging issue, increasing the stepper power is not needed.

The issue is the tolerances between the metallic and plastic insulator extruder parts, it seems that in mine there were a little difference between them, so any retracting of the filament will put the mildly molted plastic where those parts bind, the plastic will expand due to heat and this clogs it.

I have re-tightened the extruder in relation to the plastic insulator part (really tight) to avoid any possibility of plastic getting there (at the same time I switched to the white PLA, I was using the green sample filament that comes with the printer) and modified SFACT to remove the filament retraction command (it should be something like G1 E-10 F2000) and haven't clog a single time since then. Even this morning I just loaded a new stl part and print immediately without any extruder issues

stratogavster
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Post by stratogavster »

To Lioric....

How have you measured backlash?

My machine is so new and i'm so new to this i've not even managed to try slicing yet (just using readymade gcode)

Knowing that there is backlash compensation could help things!

Thanks

:)

Lioric
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Joined: Wed Aug 15, 2012 1:13 am

Post by Lioric »

Probably better if we can open a new thread, or even better a wiki or something that we can collect this information and avoid reading pages of threads looking for these details.

Anyway, yes there are tons of ways (well at least several) to measure backlash, but probably easier will be using a calibration object. This is simple and has produced great results on my machine:

http://www.thingiverse.com/thing:5745

After the lash calibration with that "thing", the size of the objects is fixed. Initially it was 19.5mm or so on each side, after calibration the resulted print was 20.1mm per side

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