Geeetech

I have installed drv8825 stepper drivers vref set about 0.65v The 3 links (caps) are in 1/32 steps. Before changing firmware x axis travels halfway across print bed. Y axis the same. This is to be expected.
Changed the #define DEFAULT_AXIS_STEPS_PER_UNIT {80,80,2560,93} // MXL, Z M8=1.25, MK8 To: {160,160,2560,93}
Still travels half the distance.
tried changing #define DEFAULT_MAX_FEEDRATE {400, 400, 2, 45} To: {800, 800, 2, 45} Still the same.
Tried different model Geeetech firmware and it does the same. Firmware compiles and uploads without a problem.
Help would be appreciated.

What is probably happening here is the eeprom settings are still set for the old settings. From what I understand, any setting saved in the eeprom will be what the printer uses no matter what you put in the firmware configuration.h file, and I know from experience that the settings you changed are one that's saved in the eeprom, this has gotten me before also.

There are multiple ways to change the eeprom settings. The easiest for me was to connect with repetier host and under config along the top is "firmware eeprom configuration", and under here you will find all these same settings and you'll just have to change the ones you need and save it. You can also change them using the lcd screen, I believe their in the motion part of the menu. I'm not near my printer to check exactly where. The only thing to remember when using the lcd, you will need to select "save eeprom" otherwise when the printer is booted up again it'll have the old values still.

Hope this is the cause of your issue and helps.

Thanks that worked. In MOTION settings and Reptier Host. I was using simplify3d. And Adruino IDE

It is a good custom to clear the eeprom settings after you uploaded a new firmware with new configuration, so the old eeprom settings will not get in the way.

re: axis per unit calculations.
I had the same problem with the z axis set at 2560 micro steps per mm
this is correct if you are using 8mm x 1.25 pitch threaded rod:
calculation:
1.8deg /step
360 deg / 1.8 = 200 steps per revolution
1 revolution at 1.25 pitch is 1.25mm so 200 steps is 1.25 mm
200 /1.25 = 160 steps per mm
16 microsteps per step set at controller
160 steps x 16 microsteps = 2560 microsteps per mm
BUT Geetech did not supply me with 8mm x 1.25 mm rod
I have chinese 5/16 " acme thread ... which has pitch of 0.217" or (2.17 x25.4=) 5.511mm
Check this by measuring distance to the base on z axis at any point , rotate the shaft once and re-measure. difference should be 5mm
so : 200 steps / 5.511 = 36.291 steps per mm movement
36.291 x 16 = 580.657 micro steps per mm