The OR is used to select the "best fit" resource for an operation.  The resource with the earliest scheduled completion date is used.  Once an OR resource has been selected, all other OR resources are not scheduled in that job’s routing. If an OR selection falls within the Or time fence, the operation is locked on the selected resource using the operation option Lock Selection.  Any number of OR resources can be associated with an operation up to the maximum operation count of 500 operations per job. 

In the example below, operation 10 can use Cell 1 or Cell 2 or Cell 3.  Note that the setup time and runtime can be different for each OR command:

You can mix AND commands with OR commands.  In the example below, operation 10 can use:

1. Mill 1 and Mach Team 01 or
2. Mill 2 and Mach Team 02 or
3. Mill 3 and Mach Team 03