What is an operation ?

Four linked operations

    Operations are the basic entities in OptiLine, they represent the tasks to be performed on the line. An operation is graphically represented by a rectangle in the Precedence Graph in the Operations Tab.
    More rigorously, an operation is an indivisible amount of time to be allocated to one and only one workstation in the line. An operation is assigned as many operators as it requires (one or several), who cannot be assigned to any other operation during the entire duration of the operation. The indivisibility of an operation further means that once an operation has been started on a workstation by a (set of) operator(s), it is performed in its entirety (full duration) on that workstation, with that same (set of) operator(s).
    An operation is often of the type "fix part X to the product" being assembled. These operations establish a correspondence between the operation precedence graph and the product being assembled (see also BOM). Other operations, such as diagnostic operations, do not correspond to a mounting of a particular part to the product.

    An operation has several attributes, some mandatory, others optional, and can optionally be subject to additional constraints:

  • Mandatory attributes:
    • An operation must have a nonnegative duration. This is the amount of time it takes to perform the task represented by the operation. You have the free choice of time units used to express durations, although they must be whole numbers (floating-point durations are not accepted). Seconds and hundredths of minutes are popular time units.
    • An operation must be one of the following types: Manual or Robotic. Manual operations are not allowed to be assigned to a robotic workstation and vice-versa, for safety reasons.
  • Optional attributes:
    • An operation can be involved in one or more precedence constraint(s).
    • An operation may require more than one operator to be carried out (see above). An operation can only be assigned to a workstation with at least as many operators as the operation requires.
    • An operation can be a variant operation, i.e., be performed on only a subset of the products being assembled on the line.
    • An operation can have position constraints.
  • Optional constraints:
    • An operation can be linked with one or more other operations.
    • An operation can be unmovable, i.e. fixed to a particular workstation in the line.
    • More generally, an operation can be assigned to a zone, i.e., be constraint to be assigned to one of only a subset of all workstations.
    • An operation can be fixed, i.e. be forced to be alone on a workstation, although it may be assigned to any workstation compatible with all its attributes.