Configurable Interface For Computers Connected To NC Machines
The purpose of this interface is to exploit the capability of the machineís controls to run their programs from the computer in a manner that results in more efficient processing of parts through the machines, while still giving the operator complete flexibility. Certain older models of controls will require a hardware retrofit to enable the type of connection that makes the features described in this document possible.
Right now the operator has to go through a procedure to select each program to run. This requires the operator to walk from the loading area to the control, to then interact with the control to select and load a program, and then to walk back to the loading area. It is time consuming and inefficient.
The DRI programming system can produce a sequence of programs that can be run one after the other without the operator having to do any selection between programs. All the operator has to do is load the next sheet of material and press the START button. The programs can be ordered in coordination with the shear list, so that the operator can just take one sheet after another off of a stack brought from the shear. These program sequences can be longer than the available memory in the control, but since we have demonstrated that programs can be successfully run directly from the memory of the local computer attached to the control, there is in effect no limit to the size of the sequence that can be run.
However, machine operators have a concern about their flexibility in handling interruptions to the sequence. Suppose a slug is pulled, or a clamp is inadvertently placed at a wrong position, or a tool breaks or is set at the wrong angle? What if the shop needs a part run immediately, even though the operator is in the middle of a long sequence?
DRIís custom interface for the computers attached to the controls delivers the efficiencies described above while preserving (and enhancing) the operatorís flexibility in determining what parts should be run.
Instead of sending one long sequence of programs to the control, the DRI system sends the individual part programs, as is done presently. But it also sends a schedule that indicates the order in which the programs should be run and the number of repetitions for each program.
The custom interface at the computer attached to the control has a number of windows. One window shows the current schedule. This window will indicate which part in the sequence in presently being processed, how many repetitions are required, and which repetition it is up to.
Another window will show the current program and where the cursor is Ė in other words what characters has the control read up to during this cycle.
Another window will show the libraries of schedules (each schedule corresponding either to a job or a batch of jobs as released by the shop scheduler). Another window will show the full library of part programs.
Another window can show various statistics. An advantage of having a computer interacting with the control as parts are being processed is that accurate statistics can be tracked, generated and reported. The time to run each part and complete schedule, which parts in a schedule have been processed, load times, maintenance times and setup times, number of parts in a shift, hits on a tool since it was last sharpened, etc. All these statistics can be shown locally and, if desired, made available to managers over the network.
Another window will show operator instructions. If a tool change or clamp position change is required, it will be shown in a clear and consistent way. Since the computer can track what the current tool load and clamp positions are, it can highlight just those changes that are required for the next program. At managementís discretion, a confirmation requirement can be switched on or off. If on, the operator will have to acknowledge that the desired change has been made before the next program is run.
The key is that these windows are interactive. For example, if the operator wants to just change the block in the program that the machine is processing, he can move the cursor in its window. He can also change the place in the schedule, or the repetition count.
He can also save the present state of the schedule, load any other program or schedule and process it, and then return to the saved schedule. This gives him complete flexibility in running interrupt type tasks.