problem with steper motor

hi
first of all i want to thank you all for helping me out with my project.

i got a little problem with my stepper motor z axis under marlin firmware with ramps 1,4 board.
I´m using no microsteps, one gearset from 15teeth to 50 and after that a belt from 10 teeth to 25 onto a threadrod.

When i use these settings:

#define DEFAULT_AXIS_STEPS_PER_UNIT {15.6302,15.6302,760,760*1.1}
#define DEFAULT_MAX_FEEDRATE {500, 500, 1, 25}
#define DEFAULT_MAX_ACCELERATION {9000,9000,100,10000}

then it turns but of course not enoth just a third.

with these settings:

#define DEFAULT_AXIS_STEPS_PER_UNIT {15.6302,15.6302,1200,760*1.1}
#define DEFAULT_MAX_FEEDRATE {500, 500, 1, 25}
#define DEFAULT_MAX_ACCELERATION {9000,9000,100,10000}

then the motor just humms loud for 2 seconds and thats all.

that have i forgotten? how can i assign more steps per millimeter?
config file included
br
nubi

solved the problem by using a stronger steppermotor and removing the gearbox. its not the best solution but somehow there is a problem with settings higher than 900 turns per mm.

Why are you using gears?

The parameter is steps per mm, not turns per mm. For example, a common threaded rod used is 8 mm with 1.25 mm pitch. That results in 200 steps* 16 microsteps/step / 1.25 mm thread pitch = 2560 steps per mm.

Edited 1 time(s). Last edit at 01/21/2014 11:41AM by brnrd.

perfect super, its working, had a misscalculation and also the motor was to weak^^

one last question, got my printer working fine but from time to time it retracts lots of fillament so it skips out of the extruder, gcode is clean, there is no command to do so, printing with marlin firmware, from sd card, retraction is disabled compleatly, and its not like on every layer or after some time, its just apears random, is ther an option in the marlin firmware to disable that?
br
nubi

Retraction is set in the slicer software, or for manual retaction, in pronterface. It should not change while you are printing. Not sure what would cause it to change.

also the head moves away from the printed object on the x and y axis from time to time.

You should probably need to adjust the trimpots on the stepper motor controllers What electronics are you using?

im using a ramps 1.4 with a 2560 arduino, lcd with sd card, the funny thing is when it moves away on x or y axis it returns to the last position so its not ruining the print, but when the extruder retracts the filament pops out and thats it, its not doing that on the z axis, and its doing it on random, same g-code, once it does it once it dont, and in the middle of the print not during levelchange or so. i suspect some firmware programming.

changing the pot settings is not solving the problem, since on x and y position its returning to the exact position i´m excluding a electronig problem since it is resuming from the same spot. and problem ocures not on the z axis.

is it possible that there is a softwaresetting that moves it bach when it detects some fault?, it seems to move on x and y position to the software endstop. havent found any settings for retraction on extruder.
is it possible to deactivate any retraction movement permanently? i dont raly need it for my purpose


when using the direct from pc print its nothing doing this like. just simple print.

Edited 1 time(s). Last edit at 01/26/2014 04:49PM by nubi.

It sounds like your trimpot setting is not right. Perhaps the current is too high. How hot are your motors getting? Did you measure Vref? Ideally, you need to adjust Vref based on the specs of your stepper motors.If you have Pololu controllers, then a Vref of 0.4 V gives 1 A of maximum current on the steppers.

There's no feedback from the motor to the controller. The firmware assumes that the steppers are keeping up with the step commands and it doesn't know if the steppers are missing steps. It doesn't even know if the steppers are plugged in or if the +12V power to the steppers is on.

if the software is missing steps then how can it return to the previous position?
the motor moves vrom 15, 15, 15 to 3, 15, 15 and back to 15, 15, 15 where it resumes printing, same happens with the y axis, it simply resumes from the same spot, so it does get the response from the motor. i suppose the extruder allso tries to spinn the fillament back in. so i suspect that its some autocorrection, i will play around with the pots once more. the polu sticks get normaly warm and are cooled by a fan, the motors get about 35-39 °C x and y , z stays cold.

You haven't mentioned what slicer you're using, but check your g-code. Perhaps you can post it so others to see.

Quote
since on x and y position its returning to the exact position i´m excluding a electronig problem since it is resuming from the same spot. and problem ocures not on the z axis.

Wipe function perhaps?

There's an option in slicers to have the extruder 'wipe' itself to remove oozing

will look into it, its sounds like sutch a function^^

nope the option is disabeld so its not the whipe function

Have you compared wha the printer is doing with what Pronterface is showing in the toolpath view?

toolpathview shows all ok, no unexpected traveling, is it possible to read out what the firmware is doing? or just to disable movement into one direction in the software?

In Pronterface, load the g-code and then go to Tools and then select Edit. You can see the g-code that's being sent to the printer. You can also just open the file in a text editor. If you post your g-code, then others here can go over them to look for anything.

I think it's sounding more and more like your problem is in the hardware. What is your v-ref set to?

ok, i want to reset the vref, is there any instruction how to set it properly? something like: aply the part A with pin1 into Part B hole2.
tx

ok its moving back and forward also on the extruder. everywhere same amount forward as it was moving backward, shure its caused by the vref? its not skipping, its not dropping steps as it would do if i have the vref reduced or tuned up to the max.
that would mean that the stepstick is communicating with the board.
does the marlin firmware support a monitor to see the commands when printing from the sd card?

Someone wrote a wiki in the reprap site.

I think before you even start trying to print a g-code file, you need to first verify that all your axes are working correctly. You do that using the host software (such as Pronterface) to jog each axis independently and make sure that it's moving in the right direction and by the correct amount. You also need to make sure that it homes properly if you are using endstops like most people. Have you done that yet?

Edited 1 time(s). Last edit at 01/28/2014 05:34PM by brnrd.

well i did and the print works wonderfull, clean right dimensions no skipping steps, all just perfect, i even printet a spoolholder and some other parts already.
but from time to time it just moves to a x position and then bach where it resumes printing same with the y and extruder. i think i´ll just make a new configuration on a clean firmware and give it with that another try.

Are you printing from SDCard or from the host with the LCD?

I've seen this kind of behavior when I'm trying to pause an SD card print from the host. I click pause and assuming that it will pause, I click on Pronterface to jog y by 100 mm to bring the bed out. Because the pause didn't really happen, I would see the bed move out and then move back to the print and continue printing.

I'm wondering if your LCD controller might be sending spurious commands to RAMPS to jog an axis. Perhaps the host sw is doing it for some reason. Anyway, how about trying to print without the LCD controller? Another test is to print without the USB connection to the host. If you start the SD print from the host with the LCD disconnected, you can then unplug the USB cable and have a print running without the host and LCD.

i used a new firmware and uploaded it, seems the version i was working with was buggy, reflashed and now the third print works fine.
thanx for all the help, i was able to fix some other problems i had with it.

ok it holded just for a view prints, still same problem
switched all the stepsticks to new ones, now it runns supersmooth (old stepsticks where cheap)
is there some settings in marlin firmware that says something like: if this condition happens move this axis to home position?
its what happens, i removed the software endstops so now its trigerd by hardware endstops. and now on of the ayis moves to the endstop and then back in (like a form of calibration) and its ok, and cool, but not funny when the extruder does the same ting in the middle of the print. its not the software and not the gcode, evenno traces of the M206-208 commands.attatched my firmware to the post, realy desperate the printer works so smooth now, but impossible to leave it alone.