Because of the non-deterministic nature of manufacturing events and their impact upon manufacturing performance, manufacturing control is one of the most important tools to increase production rates.
Production control is primarily responsible for planning, initiating (production starts), monitoring, and tracking the execution of released manufacturing orders and production processes.
The task is to optimize, to the extent possible, all operations and activities within the production environment to achieve production goals and commitments. Dispatching and scheduling are used to achieve manufacturing control. Unfortunately, they are often used incorrectly as synonyms.
Production planning is the process used to define, plan, and control long-term plans. The production plan incorporates manufacturing capacity, sales forecasts and orders, and raw material requirements. Increasingly, production planning is used to plan bifurcated production operations incorporating a component-level, build-to-stock sequence that is subsequently fed into a make-to-order finished good.
Planning processes are required to ensure manufacturing is scheduled and staffed with sufficient capacity to build finished goods to meet forecast or booked orders.
Scheduling is the process used to define, plan and control near- to mid-term production plans, typically at a daily or shift level (4, 8, 12 hour increments).
Scheduling algorithms designed to account for the non-deterministic nature of manufacturing (Stochastic Scheduling) require high-quality, extensive data that can become increasingly burdensome to procure and manage.
Consequently, as the temporal aspect of the (re)schedule is reduced to near- or even real-time, the quality of the algorithms used to create the production schedule is negatively impacted.
Dispatching is a rules-based methodology designed to ensure that the operator is selecting the right material, in the right order, at the right equipment in order to globally optimize production in support of the overall production goals.
The display of prioritized material is equipment-centric and is updated in real-time based on manufacturing events as they occur. Manufacturing operational-state models are tested against easily understood rules designed to enforce the chosen methodologies (Critical Ratio, Ship Date, FIFO, Hot, Rework, Engineering, Experiment, Line Balance).
Operators are presented continuously updated dispatch lists indicating which material has the highest priority and why. In exception cases, they can immediately determine why material cannot be run on the selected equipment (SPC hold, location, batching, recipe, durables like reticle , process capability, chamber availability, etc.), and with additional integration they can drill-in to start material or resolve issues directly from the Shop Floor UI.