Hictop Prusa I3 Z Axis Trouble

Hello folks!

I just recently bought and assembled my first printer for my introduction to robotics class.

I like it alot although as soon as one issue is worked out another one pops up.

So far i have been able to deal with them myself, but now all of a sudden my z axis is not functional.

Before Problem:
*Re-flashed board with fresh Merlin code
*Set correct values

Problem:
*Motors either fighting each other, or getting 'stuck'
*Makes a terrible sound and doesn't move.

Any help would be great!
-Analogtom

move the X axis by hand to another area of the Z axis (further up probably, assuming you tried starting it near the plate), then try to move it in with the motors. does it move in another area of the threaded bar?

if yes, you need to work your bar. lubricate with wd-40 or anti seize lubricant and continue working the axis through the troubled area on the bar. eventually the groove will even itself out. Work it by hand 10-20 times then by motor 20-40 times.

if no, your X axis probably isn't level, or the motors aren't both turning the same direction. verify motors turn, and turn same direction. verify each side of the X axis is at the same point on the threaded bar as the other. even one or two threads off will create problems. I was able to put a level right on my extruder carriage to level mine out, but I have an i3 X. not a hictop.


and yes problem after problem after problem but don't let this discourage you. I am currently drilling a hole in my X axis carriage to feed the wires to my hot end through because the wires have been touching the plate and consequently knocking prints right off of it. Be creative. solve the problems for good.

If the Z axis worked prior to the reflashing of the board, then the problem probably lies in some of the parameters in the firmware. I ran into similar issues when I tried reflashing my board with a non-Hictop version of the firmware, since Hictop does not provide the Arduino sketch code to thier firmware, and I wanted to enable the EEPROM features of the firmware. Long story short, my Z axis motors would whine, move at different rates, and in general misbehave.

First, I suggest you look at the default axis steps per unit in your version of the firmware. I have found some Arduino sketches where the value for the Z axis is set too low (i don´t recall the number precisely, but it was around 398 steps per mm). Make sure it is set to 2559 or 2560. If you are using an Arduino IDE sketch to reflash your firmware, you should have the following line in the Configuration.h file:

#define DEFAULT_AXIS_STEPS_PER_UNIT {80,80,2559,94.4962144}


Second, In some of the versions of the Marlin Hictop firmwareI have seen, the maximum feedrate for the Z axis is set too high. I have seen this paramater set to 10 mm/sec. In the original Marlin firmware supplied by Hictop, this value is 5, not 10. Changing this value will correct the problem in some cases. If you are using the Arduino IDE skecth, the Configuration.h file should have the following line of code:

#define DEFAULT_MAX_FEEDRATE {500, 500, 5, 25} // (mm/sec)

Third, you might want to check the reference voltage on your Pololu a4988 drivers. For the Z axis driver, this value should be around 1.1 Volts, since it is driving 2 motors in parallel. All other Axis should be set to a reference voltage of 0.8 V

Finally, (or perhaps it should be first), make sure that both Z axis motors are conneceted with the proper polarity, or you will have them moving in opposite directions.

Hope this helps...

rmatrix do you also know the HICTOP original extrude rate i was able to dial in my axis now it seams like the extruder is off the print either does not extrude or it drags thru the first layer.

Quote:

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Originally Posted by rmatrix

If the Z axis worked prior to the reflashing of the board, then the problem probably lies in some of the parameters in the firmware. I ran into similar issues when I tried reflashing my board with a non-Hictop version of the firmware, since Hictop does not provide the Arduino sketch code to thier firmware, and I wanted to enable the EEPROM features of the firmware. Long story short, my Z axis motors would whine, move at different rates, and in general misbehave.

First, I suggest you look at the default axis steps per unit in your version of the firmware. I have found some Arduino sketches where the value for the Z axis is set too low (i don´t recall the number precisely, but it was around 398 steps per mm). Make sure it is set to 2559 or 2560. If you are using an Arduino IDE sketch to reflash your firmware, you should have the following line in the Configuration.h file:

#define DEFAULT_AXIS_STEPS_PER_UNIT {80,80,2559,94.4962144}


Second, In some of the versions of the Marlin Hictop firmwareI have seen, the maximum feedrate for the Z axis is set too high. I have seen this paramater set to 10 mm/sec. In the original Marlin firmware supplied by Hictop, this value is 5, not 10. Changing this value will correct the problem in some cases. If you are using the Arduino IDE skecth, the Configuration.h file should have the following line of code:

#define DEFAULT_MAX_FEEDRATE {500, 500, 5, 25} // (mm/sec)

Third, you might want to check the reference voltage on your Pololu a4988 drivers. For the Z axis driver, this value should be around 1.1 Volts, since it is driving 2 motors in parallel. All other Axis should be set to a reference voltage of 0.8 V

Finally, (or perhaps it should be first), make sure that both Z axis motors are conneceted with the proper polarity, or you will have them moving in opposite directions.

Hope this helps...

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