Re: Rambling hydraulic post that was: Multiple syncronized spindle question.

[Jon Elson <elson-at-pico-systems.com>]

Dave Engvall wrote:

> Hi list:
> Not that I've done this but controlling the temp of the  oil might help.
> In this case one might have to warm to start with and then cool to maintain
> but control to 0.1 C is pretty easy in a well stirred bath and you can get
> two more orders of magnitude with out breaking the bank.

All the high-end (read $100,000 plus) machines do this.  The entire spindle
head assembly is immersed in a temperature-controlled oil bath.  Some
circulate
and cool the oil, some circulate water coolant in pipes in the head.  But,
thermal
spindle growth is a major concern, and gets worse as the machines get larger.
Some extra-high end machines also have hollow ballscrews, and run coolant
through the screws to prevent expansion of them.

Jon