Bridgeport CNC Retrofit
By
Jim Glass
Jglass52@hotmail.com
www.outbackmachineshop.com


Cut my first chips only minutes ago. The CNC mill is fully functional now. It appears to work very well. A current limiting resister is installed for 5 amps. While tuning up the stepper settings I removed the resister and observed no change in performance so the resister was replaced. Need to run it now and see how everything works.

Who was it that said a laptop would not control the machine? Just to the right of the laptop is an electrical enclosure with the "E-Stop" button and a spindle reset button to use the spindle manualy. A third button will activate the oil pump.

The only Bridgeport components used are the motor contactors, fuses and a few relays. The DC power supply uses a 46 VAC, 700VA toriodal transformer. It looks like a large donut. The DC voltage at the 25,000uF capacitor is 63 VDC and about 11 amps. The 120 VAC for the power supply and the machine controls plugs into any wall outlet. The rotary phase converter only runs the spindle. There is a 24 VDC power supply installed for push button, relay, and air valve control. There is also a 12 VDC power supply 
(white box),to drive the Axuss control board and 12 VDC relays.

The tiny green relay (wired N.C.)in the center of the cabinet trips when a limit switch is contacted. The relay then opens the latching circuit of the master control relay stopping power to the steppers. The push/pull "E-STOP" button is also the limit switch over ride so it has 3 functions.

The master control relay is actually a motor contactor. Just in case I need additional DC power supplies the motor contactor can switch both.

The 4 blue relays 12 VDC and are CNC controlled (M codes) for spindle forward/revears and coolant "A" and coolant "B". The only thing left to connect. The 12 V relays will trip additional spindle motor contactors, by passing the original Bridgeport contactors.

The internet is a wonderful thing. Without the internet I never would have thought of a job like this much less attempt it.

This is my first "real" CNC machine. I think I'm going to have some fun and hopefully make some money with it.

A sincere thanks to all that gave encouragement and the knowledge to move forward.
Jim