CNC help

I was recently handed over a mess of a machine that I believe should have had cnc control all along but for a multitude of political reasons wasn't

The machine is basically a 3 axis motion controller. Axis X "the spindle" is a DC motor and drive. Axis' Y and Z are Siemens master drives. The whole thing is controlled by an S7 300 via Profibus.

Without going into details, Axis Y and Z are geared of axis X. The PLC program is written as such that none of the axis' really care where the other are (but in reality they should care as it screws up our product when they are not in sync. They are each told to go to a position without any regard as to where each other are. Because of what I believe are scan time/comm time problems these machines are only able to run at about 60% production in order to produce an acceptable product.

If anyone knows of anyone with S7 motion control experience please contact me. We are about to throw these controllers in the garbage and buy a fanuc.

I'm not clear on what system you have at the moment. Is the axis control done in the PLC CPU? I have used the FM357-2 4-axis controller for S7-300. This is a CNC controller in its own right, programmed in NC, so you can do motion coupling, tangential control and all that stuff. It should be possible to synchronise the axis motion properly with this unit. I would only consider myself a learner on this, but I found Siemens tech support to be outstanding.

You are wasting alot of money throwing away Siemens products, especially an S7-300 and MicroMaster drives. Get someone to reprogram the system and learn a little Siemens in the process.