[mikeysp]

What are your thoughts on:high speed spindle 1KW, 1.5KW, or 2.2KW; and a Brushless servo motor 759W - 1HP; (industrial sewing machine)?

why would you choose one over the other?
Pros/cons of high speed spindle?
Pros/cons/ of Brushless servo motor?

[joeavaerage]

Hi,
I have two spindles for my mini-mill. A 800W 24000 rpm VFD controlled asynchronous spindle. Its great for engraving and milling soft metals like aluminum
with small diameter tools. Its hopeless for steel which requires slower rotational speeds but much MUCH higher torque.

For this reason I made a slow speed (up to 3500 rpm) high torque (6.1 Nm cont.) spindle with ER25 toolholder with a second hand 1.8kW Allen Bradley servo.
Its great for steels, stainless etc.

Both spindles are useful....but they have wildly different characteristics, one is high speed low torque, the other is low speed high torque.

Note that you can get moderate to high torque asynchronous spindles which can give you high speed and yet have enough torque for steel but they are big
and expensive often with specialist VFDs at added expense.

The choice for you is dictated by the work you want t do. For engraving or milling in aluminum a high speed spindle would be good. If you want to cut steel
then you'll need either a really big multipole high speed spindle or a much slower but high torque servo motor.

Craig

[Al_The_Man]

One advantage in the BLDC spindle is one that is fitted with encoder and can be set up for CSF, threading and C axis for active tooling on a lathe.
Al.