Help with Steps/mm Calculation?

[itzdarkoutthere]

For my first calibration and print I went with 106.67. With it set like that the z distance between nozzle while homed and printing surface that was reflected in the firmware after calibration more or less matched my physical measurement.
My first print of the calibration cube is shorter than it is wide. It is around 24mm height and 30 mm width.

The only part of the calculation I am unsure of is the belt pitch.
Pulley Teeth: 15
Steps/rotation: 200 (1.8 degree per step)
Micro steps: 16 (Rambo 1.1b)

So assuming 106.67 is correct, then my belt pitch would be 2. I tried to measure it, but my hands are just a bit too shaky to get a measurement that precise.

I ordered the rostock max Feb 27 and received it Mar 7.

One other thing i just realized, I did not change the pully teeth number in the firmware configuration.h to 15. It is currently at 20. Would this have factored into my skewed callibration cube?

Anyway, before I do my next print I would just like to be absolutely sure what went wrong here. I've found a bunch of useful information here in this forum along the way. This is my first 3d printer, and so far I am loving it. From bits of information I pulled together I was able to get my heated bed from maxing out at ~76c to hitting 85c in just over 5 minutes. In the next couple of days, I plan to post a topic with everything I did, since it seems quite a few people were having similar issues. I just want to play with it a bit more first to see how well it performs.

[foshon]

For my first calibration and print I went with 106.67. With it set like that the z distance between nozzle while homed and printing surface that was reflected in the firmware after calibration more or less matched my physical measurement.
My first print of the calibration cube is shorter than it is wide. It is around 24mm height and 30 mm width.

The only part of the calculation I am unsure of is the belt pitch.
Pulley Teeth: 15
Steps/rotation: 200 (1.8 degree per step)
Micro steps: 16 (Rambo 1.1b)

So assuming 106.67 is correct, then my belt pitch would be 2. I tried to measure it, but my hands are just a bit too shaky to get a measurement that precise.

I ordered the rostock max Feb 27 and received it Mar 7.

One other thing i just realized, I did not change the pully teeth number in the firmware configuration.h to 15. It is currently at 20. Would this have factored into my skewed callibration cube?

Are you using the SeeMeCNC version of the repetier firmware or?

Anyway, before I do my next print I would just like to be absolutely sure what went wrong here. I've found a bunch of useful information here in this forum along the way. This is my first 3d printer, and so far I am loving it. From bits of information I pulled together I was able to get my heated bed from maxing out at ~76c to hitting 85c in just over 5 minutes. In the next couple of days, I plan to post a topic with everything I did, since it seems quite a few people were having similar issues. I just want to play with it a bit more first to see how well it performs.

[itzdarkoutthere]

As it happens, I have searched the board quite a bit and I believe my numbers to be correct. I was just hoping someone could tell me for certain....

[foshon]

As it happens, I have searched the board quite a bit and I believe my numbers to be correct. I was just hoping someone could tell me for certain....

Are you using 20 tooth pulleys or 15? If you are using Marlin then you have to calculate your s/pmm. If you are using repetier then you enter the information and the calculation is automatic.

[itzdarkoutthere]

As it happens, I have searched the board quite a bit and I believe my numbers to be correct. I was just hoping someone could tell me for certain....

Are you using 20 tooth pulleys or 15? If you are using Marlin then you have to calculate your s/pmm. If you are using repetier then you enter the information and the calculation is automatic.

15, repetier. Doesn't seem it calculated it for me, it was originally 106.67 with 20 teeth, 2 belt pitch, 16 microsteps, 200 steps/revolution.

Anyways, I have uploaded what I believe to be correct and re-calibrated. Calibration cube started printing a little bit ago, already looking better than the first time around. Hopefully after this, the only task I will have left is to deal with the delta arms.

/e
Print is finished. MUCH better! It think it was pushing out just a bit too much filament and, as expected, my delta arms need a little work. But not nearly as much as I had originally suspected.

So to sum it up for anyone else that got their rostock max the same time I did:
steps/mm 106.67
BELT_PITCH 2
PULLEY_TEETH 15
STEPS_PER_ROTATION 200
MICRO_STEPS 16

[foshon]

Do you not have this in your configuration.h?

Code: Select all

#include "pins.h"

// Uncomment the following line if oyu are using arduino compatible firmware made for Arduino version earlier then 1.0
// If it is incompatible you will get compiler errors about write functions not beeing compatible!
//#define COMPAT_PRE1

/* Define the type of axis movements needed for your printer. The typical case
is a full cartesian system where x, y and z moves are handled by seperate motors.

0 = full cartesian system, xyz have seperate motors.
1 = z axis + xy H-gantry (x_motor = x+y, y_motor = x-y)
2 = z axis + xy H-gantry (x_motor = x+y, y_motor = y-x)
3 = Delta printers (Rostock, Kossel, RostockMax, Cerberus, etc)
Cases 1 and 2 cover all needed xy H gantry systems. If you get results mirrored etc. you can swap motor connections for x and y. If a motor turns in 
the wrong direction change INVERT_X_DIR or INVERT_Y_DIR.
*/
#define DRIVE_SYSTEM 3

// ##########################################################################################
// ##                               Calibration                                            ##
// ##########################################################################################

/** Drive settings for the Delta printers
*/
#if DRIVE_SYSTEM==3
    // ***************************************************
    // *** These parameter are only for Delta printers ***
    // ***************************************************

    /** \brief Delta drive type: 0 - belts and pulleys, 1 - filament drive */
    #define DELTA_DRIVE_TYPE 0

#if DELTA_DRIVE_TYPE == 0
/** \brief Pitch in mm of drive belt. GT2 = 2mm
*/
#define BELT_PITCH 2

/** \brief Number of teeth on X, Y and Z tower pulleys
*/
#define PULLEY_TEETH 15
#define PULLEY_CIRCUMFERENCE (BELT_PITCH * PULLEY_TEETH)

#elif DELTA_DRIVE_TYPE == 1

/** \brief Filament pulley diameter in milimeters
*/
#define PULLEY_DIAMETER 10

#define PULLEY_CIRCUMFERENCE (PULLEY_DIAMETER * 3.1415927)

#endif


/** \brief Steps per rotation of stepper motor
*/
#define STEPS_PER_ROTATION 200

/** \brief Micro stepping rate of X, Y and Y tower stepper drivers
*/
#define MICRO_STEPS 8

    /** \brief Number of delta moves in each line. Moves that exceed this figure will be split into multiple lines.
    Increasing this figure can use a lot of memory since 7 bytes * size of line buffer * MAX_SELTA_SEGMENTS_PER_LINE
    will be allocated for the delta buffer. With defaults 7 * 16 * 30 = 3360 bytes. This leaves ~1K free RAM on an Arduino
    Mega. */
    #define MAX_DELTA_SEGMENTS_PER_LINE 30

    // Calculations
    #define AXIS_STEPS_PER_MM ((float)(MICRO_STEPS * STEPS_PER_ROTATION) / PULLEY_CIRCUMFERENCE)
    #define XAXIS_STEPS_PER_MM AXIS_STEPS_PER_MM
    #define YAXIS_STEPS_PER_MM AXIS_STEPS_PER_MM
    #define ZAXIS_STEPS_PER_MM AXIS_STEPS_PER_MM

[dsnettleton]

Since you're using the repetier firmware, make sure steps/mm in the EEPROM match those in your firmware. Speaking from experience, one thing that can cause Z dimensions to disagree with X and Y dimensions is an incorrect setting for PRINTER_RADIUS. You'll know you have this problem if you have a level printer bed, but the hot end is closer or farther away from it as you move away from the center.