A badly scanned picture showing the front of the mill with the keyboard and monitor supported by a monitor arm.
A badly scanned picture showing the front of the mill with the keyboard and monitor supported by a monitor arm.
The
power cabinet on the rear of the machine showing, from the upper left, a 220V-110V transformer, the main voltage matching transformer (in case you have 440V 3 phase), the main power switch with three big fuses (I've never blown these!). From the middle left you have a metal plate which replaced a pcboard (the EAF board?) on which are mounted two solid state relays that control the mist and flood coolants, and the Opto22 rack which controls the spindle relays, coolants, estop (in and out from the PC) and lube oil level sense. At the middle right are the forward and reverse spindle relays. Below these relays, at the lower right is the spindle motor overload heater. The bottom left of the cabinet is dominated by miscellaneous (!) fuses and terminal blocks used to connect everything together.
The electronics cabinet on the right side of the machine upon which the monitor arm is hung. The big white box is a 100MHz Pentium PC (intel MARL motherboard, 32MB RAM, 1.6GB WD hard drive, ATI PCI video card, extra parallel port card, 10MBs PCI Ethernet card, and a 4 axis Servo To Go card). The rainbow ribbon cables connect the Servo To Go card to a junction board that I made from perfboard. The junction board has connectors that mate to the original encoder cables and some VN10KM FETs and resistors used to translate 24Volt logic to 5Volts for the home switches. This was a case of trying to preserve too much of the original wiring. In later machines I used standard 50 conductor ribbon to screw terminal adapters from Advantek, and sense the home switches directly with the Servo To Go card (the input pin is pulled up to the PC's 5 volts with 1K and the home switch closes to ground). The black cable coiled up at the middle right is Ethernet.
Here is a close up shot of the servo amps from Servo Dynamics. This is a rack with places for four amps and a power supply. What they do for DC power is rectify the 110 volt line and filter it with that big blue capacitor. The little board above the cap is a "snubber". As it was explained to me this dampens the inductive kick which emanates from a servo motor coming to an abrupt stop from a high speed. It was an option that the salesman said I needed, so I got it! You can see the adjustment pots and status lamps on the front edge of the three amps. In the bottom of the cabinet are (from right to left) the 110 volt to 24 volt power transformer, two of the motor relays, the blue 24 volt filter cap with a matching huge series filter inductor behind it, the bridge rectifier for the 24 volt supply, the third motor relay, and finally the estop relay on the right. The motor relays are very large pilot duty relays made by Sylvania that disconnect the servo motors (both poles) from their respective amps and short the motor poles together for maximun electronic braking effect during an estop. This (among many other requirements) is part of compliance with NFPA79 safety standards for machine tools. I don't know if the rest of what I did still complies with this standard, but this was a feature I liked a lot, so I kept it.