Re: Spindle motors

Hello everyone, high speed spindles are a real enigma. What I did a
few years ago is establish a strawman to aim for. After searching I
found the NSK America, ASTRO-E 250 which runs continuously at 2,000 to
25,000 with a maximum output of 105 watts. "Withstands 5,000 hours of
continuous use", and is air cooled. Yes that is enough to engrave
steel, brass etc. It is a brushless motor complete spindle, with speed
controller for over $2,000. NSK makes a complete line of high speed
spindles, and the ASTRO-E 250 is the cheapest.

There spindles run up to over 50,000 rpm - continuous duty chcle, and
are machining spindles. The real high speed spindles are water cooled.

Well I did not have $2,000 so I started a search to find a suitable
alternative. Well after a lot of searching, studying - yes I
considered RC brushless IRK Outrunner motors, and got no where. I
asked KDN Tool, http://www.kdntool.com and Ken Cardolino found a
solution. Take a look at "High Speed Spindle Attachment For The X2
Mini Mill", on the KDN Tool web site. 5,000 to 20,000 rpm, with built
in speed control, continuos duty cycle with forced air cooling, 6
collet sizes, and $110. You can also purchase a mount to mount the
spindle on to a SIEG X2 stock spindle.

I don't know how much money I spent on books about permanent magnet
motors, brushless motors, power converters, circuit designs for
controllers, and hours reading all the stuff. By the way if you look
hard enough you will find a water cooled, RC, high speed, brushless
motor, but it's going to cost you $350. Plus the cost of a power
converter, and speed controller. And you need to design and machine a
multiple collet system with no runout. Don't forget to ballance the
whole assembly. And you better have the right kind of bearings in the
spindle end.

This whole question is interesting because of engraving machines. They
all use high speed spindles, are not water cooled, are continuous duty,
and are also used for machining prototype work. The engraving machine
motors and controllers are also very expensive.

Bill