Z axis not retracting

[Edwinrist]

Hello, I've just started experimenting with a new x4, and I tried the bolt pattern wizard in Mach 3 for something simple. 6 holes, .5" deep, .25 rapid height clearance. Mach 3 calculated and showed .5" movement down, followed by .75" movement up, however the x4 Z axis did not move up. fortunately I tested with extra z clearance, but the Z axis traveled a total of 3" with no upward movement. is there something wrong in the electrical box? it jogs and homes fine.
Thanks

[neilw20]

Most likely the gibs a bit tight, but the motor tuning maybe a bit fast.
Moving up and down with the jog keys and the shift key held should not lose position.

[SDesigns]

Is the motor turning?
If so, it could be a loose grub screw on the coupler.

[neilw20]

I've had a loose stripped grub screw too.

[SDesigns]

I broke the coupler!

It was caused by a chain of events really.
When you are finished working on the machine, are you are ready to shut it down, always retract the Z axis fully. (G53Z0.)
Here is why......
If the gas strut is left under load for extended periods of time, it wears out, the gas leaks out, and it becomes ineffective. This then places a large on the load on the coupler when the Z axis stepper is asked to lift the head.

When removed, my gas strut was found to offer no support at all, nothing.

[neilw20]

Gas strut is installed upside down.
Small shaft at bottom, so oil stays on the seal.
Buy a longer one - 380 mm. I will send link on this mod later.
Extra 80+ mm for nothing!!

[SDesigns]

Hi Neil,

Will it last longer if the oil is on the seal?

I like the idea of the extra 80mm. is that an extra 40 down and 40 up?

[neilw20]

If you look at the spec sheet on the struts they are designed to have the seal that way, so there is oil in it.

My strut was replaced march 2008 and is still as good as the day I installed it.

Make sure you only have sufficient charge for 20KG force each side, or 40KG total for one.

Replace with a longer strut. Here's how...

http://www.cnczone.com/forums/syil_p...r_weights.html

[mactec54]

Edwinrist

You have lots of good mechanical things to check & do, Post your program as well, as there may be something in your program, that is not right as well, just save the program as text, & you can post it here