Need Help!- Spindle motor size Vs feeds & speeds

[TMaster]

I've been running a 1/4hp 3450rpm motor for about 3 years on my Taig mill. I've been cutting Aluminum most of the time at the max 9800rpms with the highest pulley setting, at around 4 ipm, with depths up to .100" depending on the cutter size and cooling.

I remember talking to a machinist a few years ago that runs large CNC machines and he said he cut aluminum around 800-1200rpms.

I'am guessing that the 1/4 motor is not holding the torque and rpms, and thats why i have to cut it at such a high rpm. I am self taught and I just want to get someone elses opinion before I upgrade to a 1/3 hp motor. The 1/4hp motor i have is 9 lb's and the 1/3hp is 15 lb's weight.

Also if my guess is correct I wouldnt need such a high rpm base motor, Could I get by with a 1725rpm motor instead of the 3450? THis would put my max speed around 5,000rpms instead of 10,000.

[rowbare]

And I drive my car at 30 MPH...

As in the above statement, what the machinist told only makes sense in the context of what he is doing. For all you know he is pushing a 1.5" cutter with a 1" DOC when he is running at that speed.

On a Taig you will be using primarily 3/8" and smaller cutters so spindle speed is your friend. Generally speaking, for a given material and cutter, the spindle speed will determine how fast you can push the cutter through the material. Spindle horsepower and machine rigidity (including the cutter) will determine how deep a cut you can make at that speed.

Google "speeds and feeds" and read a few of the articles.

[zaebis]

taig will run out of rigidity long before it runs out of motor power. i am dealing with desktop cnc machines now and what taig has is quite adequate.

2600lbs open table HAAS has 2hp and it is doing just fine. if you want more IPM and DOC you will have to invest in cast iron !!! lots of it.