The X and Z axes are controlled by Yaskawa Sigma 7 ServoDrives. Both ServoPacks are the Sigma 7 SGD7S-180A00A 002 ServoPack with the X axis ran by the Sigma 7 SGM7G-20A6A6E ServoMotor and the Z axis ran by the Sigma 7 SGM7G-20A7D6S ServoMotor. This was a very simple replacement as the mounting lined up for the ServoMotors and the ServoPacks are very simple plug and play with the Centroid OAK board.
These axes move a Duplomatic BSV-N 200 12 tool turret. This turret has various sensors that plug into the OAK board with the required solenoids and motor contactors being controlled directly by the OAK board. This allows that OAK to easily move the turret to the desired tool with the 10 millisecond precision needed according to the turret manual. This turret also allows the use of live tooling ran by a Fanuc 3s AC spindle motor controlled by a Altivar Machine ATV320D11M3C VFD.
The live tooling functionality provided additional problems for the main spindle however. The main spindle is driven by a belt drive that is attached to a Fanuc 18s AC spindle motor controlled by a Emerson Commander SK 4203 VFD. As having a large spindle motor run in position mode is difficult to accomplish we opted for adding a ServoMotor into the belt system. This is a Sigma 7 SGM7G-20A7D6S ServoMotor controlled by a Sigma 7 SGD7S-180A00A 002 ServoPack. Additionally to avoid having the spindle motor drive the ServoMotor at speeds that would damage it, a clutch was added to the system. This clutch is a Mönninghoff type 546.32.4.4 electromagnetic clutch that is controlled via relay by the OAK board. We also added a 10:1 planetary gear reducer to the ServoMotor to allow for lower speeds, higher torque, and higher accuracy. This is a Porovin Technology High Precision Reducer model number TFG120-010-S2-P2 gear reducer. It was very simple to attach to the ServoMotor and we created a mounting system to mount the entire assembly to the cast body. This is shown below from a couple different angles.
Another problem that had to be solved was with the main spindle encoder. Installed in the original machine was a main spindle resolver. This resolver wouldn't send the correct signals to the OAK board as that needs a Quadrature Encoder signal. To remedy this we purchased a VEGA 2796500 - COMPACT DIN RAIL RESOLVER TO DIGITAL CONVERTER BOARD, to convert the resolver to the needed Quadrature Encoder signal. This board is shown below installed into the machine. This board was very simple to plug in and is able to do what we needed to do.
We needed to make a new coolant tank and coolant pump mount as neither of those came with the machine. We also added a new monitor stand for the HP PC running CNC12. Then everything was given a new coat of paint to really make it look new. Below are some images of the control cabinet and the exterior of the machine.
We then tried a solution in the creation of a G code macro.
Centroid provides many different System Variables that can be accessed during machine runtime. These variables allow us to get the Current Encoder count and the Encoder count of the last index pulse. Using those variables we can accurately index the C axis. Then any hole that needed to have a countersink, would have both operations occur on the same encoder pulse. Now the machine is able to repeatably index the C axis for drilling operations and then do continuous mill-turn operations for less accurate operations. We have the example part below that worked quite well on the machine.
