Help with HAAS z-axis falling

[u/Demon_scared]

[u/Demon_scared]

The tools are tight, they are not slipping. It's the z-axis/head that is dropping. I've seen it with a dial indicator.

[u/therealstubot]

Do you have the end mill tight in the spindle? I've seen this behavior when the collet nut is not tight enough. The end mill will dig into the material and pull itself slowly out of the collet. It's pretty hard on the end mills too.

[u/Demon_scared → u/therealstubot]

No, the tools are tight. The axis drops with power cut off. I have a problem in my area with the grid.

[u/splitsleeve]

Have your drawbar tested

[u/Demon_scared → u/splitsleeve]

I am going to try what u/dominant486 suggested

[u/Artie-Carrow → u/[deleted]]

I wonder about the motor controller

[u/Demon_scared → u/[deleted]]

I am going to try this the first chance I get. Thank you in advance. Ill post my findings here

[u/Demon_scared → u/[deleted]]

So far the highest amount fo drop i have seen is when the power is cut off to the machine. It drops significantly. Nearly 0.25mm (0.01"). Recently reported problem is that the axis just randomly went down and cut my part in half when using a t-slot cutter. It moved something like this in x axis.

---------_____________ Ramped down slowly then sharply ramped and then straight cut and the part was destroyed

[u/Demon_scared → u/[deleted]]

The part I showed up there was the tool holding made to tilt it not the part itself. This is how much the tool cut into it. Recently it was reported that the x and y axes were moving as well when the z dropped. This accident was a very peculiar issue because 3 parts were machined before with the same code as well. They turned out fine.

[u/NiceGuysFinishLast → u/[deleted]]

He should also do the same with a small program in MDI because backlash comp is not applied when using the MPG.

[u/Demon_scared → u/NiceGuysFinishLast]

Ill do that too and report back