prusa i3 z-axis problems

hi,
im new to all this and trying to build a prusa i3 to get my grandson into it.

so far ive got the build together and ramps installed.
but when I try to lower the z-axis to level the print bed it stops about 10mm from the bed and wont move any lower.
it will move up no problem but wont go no lower than previously mensioned.
help please.

So it doesn't reach the endstop?
Are you trying to home the Z axis or move it down via the manual controls?

Steve

hi steve,
it was when I was doing it manually.
ive managed to sort it out now though.
don't ask me how but I tried one thing after another and it seems to be behaving at the momwnt.
no doubt I will soon be back asking for more advice though.


thanks again
Mark.

I hope i can steal this topic for a bit..

We have a problem with our z-axis on our prusa i3 hebhestos, the problems is that the z axis will make a loud grinding noise..

I can fine control the printer in pronterface and then there is no problem with any axis

however when i try to print in cura, it starts by homing all the axis, then it will lift the z axis, but it just stands still with a huge grinding noise. and after that it moves to the center and starts printing.

We have tried the following.

Adjusting the voltage on the stepstick driver to the correct amount stated in BQ documentation.
Adjusting alot of feedrates and accelleration with absolutely no clue of what im doing..

Can someone help me, i myself thing is something about the acceleration on the z-axis as it seems that it cant keep up !

What is the DEFAULT_MAX_FEEDRATE set at? try these values

#define DEFAULT_MAX_FEEDRATE {500, 500, 2, 25}

Steve

Quote
supernielsen
I hope i can steal this topic for a bit..

We have a problem with our z-axis on our prusa i3 hebhestos, the problems is that the z axis will make a loud grinding noise..

I can fine control the printer in pronterface and then there is no problem with any axis

however when i try to print in cura, it starts by homing all the axis, then it will lift the z axis, but it just stands still with a huge grinding noise. and after that it moves to the center and starts printing.

We have tried the following.

Adjusting the voltage on the stepstick driver to the correct amount stated in BQ documentation.
Adjusting alot of feedrates and accelleration with absolutely no clue of what im doing..

Can someone help me, i myself thing is something about the acceleration on the z-axis as it seems that it cant keep up !

We got it to print by using simplify3d. it works because it sets the z axis to home and just go to the middle without lifting it, which seems to be the problem with cura.
However this is not a 100% good solution but atleast it prints, and it prints pretty good.

These are my values:
#define DEFAULT_MAX_FEEDRATE {250, 250, 3.3, 25} // (mm/sec)
#define DEFAULT_MAX_ACCELERATION {3000,3000,100,10000}

I found the problem travel speed in cura were way to high for z-axis, i changed it in the g code to a speed the z-axis could handle..