Triac VMC Servo // Z-Axis Dropping on power off

**danielbriggs** · 09-07-2018

Originally Posted by battwell

does your machine orient the spindle? thats the bit im stuck on at the moment

You mean if it knows the exact angular position of the spindle?

No...
Currently fitted is a SEM MT30U4-36 and Sprint 1800 drive.
That has a tacho on it; but anything better than that i.e. for rigid tapping etc you'd need a new spindle with resolver or encoder and a new drive.

**battwell** · 09-07-2018

-required for tool changer to align the drive dogs of the spindle.
original fanuc control did it- but im having trouble getting it to stop in the right position.
stupid thing.lol
mine has the control techniques lynx drive- not sprint- so already mains isolated :-)

**m_c** · 09-07-2018

Machines with the drive dogs, IIRC early ones used a drop in solenoid to locate the spindle, then later ones used a sensor (possibly alos with a programmed time delay).

Denford stopped fitting the drive dogs at some point though, as they aren't needed for the relatively low power spindle.