need help with Mendel90 z-axis speed

Hello!

I just finished a Mendel90 machine on megatronics_v3 electronics.

I've uploadfed Megatronics-Marlin_v1 firmware.

Everything works fine then i trying to move/extrude from pronterface.

Now then i press print button and machine returns all 3 axis to 0 my mendel90 CAN'T positioning Z axis to get extruder downward to bed.
It looks like machine trying to do it too fast, but pronterfaces settings and marlin's fw (Configuration.h (DEFAULT_ACCELERATION)) doesn't changes this effect.

Please help me with direction of next step.

Edited 1 time(s). Last edit at 11/19/2014 04:54PM by r0m.

The firmware should cap the speed as well.

Use the settings from the version of Marlin on my github.

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[www.hydraraptor.blogspot.com]

thank you, but i can't see my Megatronics3 in your Marlin configuration.

No but you can see the Z speeds and accelerations.

Or you could try Neil Darlow's more recent version of Marlin configured for Mendel90.

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[www.hydraraptor.blogspot.com]

I don't know how the Megatronics V3 differs from the V2 but my firmware only has selections for Megatronics and Megatronics V2.0.

Regards,
Neil Darlow

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I try to write with consideration for all nationalities. Please let me know if something is unclear.
Printing with Mendel90 from fedora 25 using Cura, FreeCAD, MeshLab, OpenSCAD, Skeinforge and Slic3r tools.

i have tryed to add this to configuration.h in Mechanical Settings section.

#define DEFAULT_AXIS_STEPS_PER_UNIT {80,80,200*16/1,E_STEPS_PER_MM} // Mendel90 with Wades and Stoffel15 bolt
#define DEFAULT_MAX_FEEDRATE {400, 400, 4, 30} // (mm/sec)
#define DEFAULT_MAX_ACCELERATION {2000,2000,150,5000} // X, Y, Z, E maximum start speed for accelerated moves. E default values are good for skeinforge 40+, for older versions raise them a lot.

#define DEFAULT_ACCELERATION 2000 // X, Y, Z and E max acceleration in mm/s^2 for printing moves
#define DEFAULT_RETRACT_ACCELERATION 5000 // X, Y, Z and E max acceleration in mm/s^2 for r retracts

//
#define DEFAULT_XYJERK 10.0 // (mm/sec)
#define DEFAULT_ZJERK 0.0 // (mm/sec)
#define DEFAULT_EJERK 10.0 // (mm/sec)


and a result is printer after endstops cheking goes to position 005 on Z axis and starting to print from above. (ofcouse,i've Z_MAX_POS. it's ok)

So i'm almost done, please help me a little more =)

When you say "after endstops cheking goes to position 005 on Z axis " do you mean it moves to 5mm from the bed or do you mean it thinks it is at 005 when it is at the endstop?

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[www.hydraraptor.blogspot.com]

it normally checks endstops on Z (and X,Y) and after that goes down just to 005 (on LCD is also 005),not down to bed, it stays almost at top, and just after starting to print "to air" (thinking it's on bed now)

Edited 1 time(s). Last edit at 11/23/2014 01:55PM by r0m.

So it seems you have the Z axis configured for the limit switch at the bottom instead of the top.

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[www.hydraraptor.blogspot.com]

oh, it's so simple thought, i must be get it by my self.
Thank you!

I took this settings from your configuration.h (with only difference in #define Z_HOME_DIR = (-1) not +1, as is in your file :


#define INVERT_X_DIR false // for Mendel set to false, for Orca set to true
#define INVERT_Y_DIR false // for Mendel set to true, for Orca set to false
#define INVERT_Z_DIR true // for Mendel set to false, for Orca set to true
#define INVERT_E0_DIR true // for direct drive extruder v9 set to true, for geared extruder set to false
#define INVERT_E1_DIR false // for direct drive extruder v9 set to true, for geared extruder set to false
#define INVERT_E2_DIR false // for direct drive extruder v9 set to true, for geared extruder set to false


// ENDSTOP SETTINGS:

#define X_HOME_DIR -1
#define Y_HOME_DIR -1
#define Z_HOME_DIR -1


#define X_MIN_POS -100
#define X_MAX_POS 100
#define Y_MIN_POS -100
#define Y_MAX_POS 100
#define Z_MIN_POS 0
#define Z_MAX_POS (215-0.1)

// The position of the homing switches. Use MAX_LENGTH * -0.5 if the center should be 0, 0, 0
#define X_HOME_POS (X_MIN_POS - 1)
#define Y_HOME_POS (Y_MIN_POS - 1)
#define Z_HOME_POS (215.0)

#define X_MAX_LENGTH (X_MAX_POS - X_MIN_POS)
#define Y_MAX_LENGTH (Y_MAX_POS - Y_MIN_POS)
#define Z_MAX_LENGTH (Z_MAX_POS - Z_MIN_POS)



//Manual homing switch locations:
// For deltabots this means top and center of the cartesian print volume.
#define MANUAL_X_HOME_POS 0
#define MANUAL_Y_HOME_POS 0
#define MANUAL_Z_HOME_POS 0

//// MOVEMENT SETTINGS
#define NUM_AXIS 4 // The axis order in all axis related arrays is X, Y, Z, E
#define HOMING_FEEDRATE {35*60, 35*60, 4*60, 0} // set the homing speeds (mm/min)



#define E_STEPS_PER_MM ((3200 * 39.0)/(11.0 * 6.75 * 3.142))

#define DEFAULT_AXIS_STEPS_PER_UNIT {80,80,200*16/1,E_STEPS_PER_MM} // Mendel90 with Wades and Stoffel15 bolt
#define DEFAULT_MAX_FEEDRATE {400, 400, 4, 30} // (mm/sec)
#define DEFAULT_MAX_ACCELERATION {2000,2000,150,5000} // X, Y, Z, E maximum start speed for accelerated moves. E default values are good for skeinforge 40+, for older versions raise them a lot.

#define DEFAULT_ACCELERATION 2000 // X, Y, Z and E max acceleration in mm/s^2 for printing moves
#define DEFAULT_RETRACT_ACCELERATION 5000 // X, Y, Z and E max acceleration in mm/s^2 for r retracts

#define DEFAULT_XYJERK 10.0 // (mm/sec)
#define DEFAULT_ZJERK 0.0 // (mm/sec)
#define DEFAULT_EJERK 10.0 // (mm/sec)

----------------------------------------------------------------



but now, homing on Z is OK, but then i'm trying to lift my printer down to 215 it reaches only aprx. 60% of his height (of his real 215mm), LCD screen displays 215, but actually printer runs only about 130mm of 125mm.

oh yes, and ofcoz with previous settings this wasn\t happening, the printer travells exactly as shown in pronterface and on LCD screen.


this stucks me down again...

Edited 2 time(s). Last edit at 11/24/2014 06:05PM by r0m.

have you tried to adjust your stepper settings? i had the similar issue and realized that the Z axis screw i used isnt what nophead uses but it is adjustable... when i figured that out i was able to increase the steps 200 at a time till the distance traveled matches what i tell it in pronterface... then send a command M114 to find out where the Z axis really is..if still off, keep adjusting...you can use a prusa calculator for your motors and lead screw and belt to get your approximate step needed

Edited 1 time(s). Last edit at 01/03/2015 01:43AM by 09zx-6r.

Err, it isn't "approximate"!

If you put the correct figures in Prussa's calculator then it will give you the exact steps to use. If you're not getting the correct result then you input a wrong number (most probably you are using a different pitch thread on your rods).

ok sorry,,,, its accurate...