Facility Planning and Materials Handling
Layout, flow, space, and handling are evaluated with a small set of quantitative tools.
Layout types
Process (job shop) layouts group by function: flexible but travel-intensive. Product (flow line) layouts follow the sequence: low travel, brittle to change. Fixed-position layouts bring resources to an immobile product. Cellular layouts group part families using group technology, cutting setup and travel time.
Analysis tools
Build a from-to chart of flows and a relationship chart from Systematic Layout Planning. The load-distance score is Σ (flow × distance), and the objective is to minimize it. Distance metrics matter: rectilinear (|Δx| + |Δy|) for aisle travel, Euclidean for straight-line, and squared Euclidean when minimizing travel time. Flow dominance is the standard deviation of flow divided by the mean. CRAFT improves an existing layout by pairwise department exchange; ALDEP and CORELAP construct layouts from scratch.
Space and handling
Space requirements come from operator, machine, material, and aisle needs; aisle width depends on vehicle, load size, and clearance. The unit load principle says handle material in the largest practical unit. Equipment selection: conveyors for high volume on a fixed path; forklifts and AGVs for flexible paths; AS/RS for dense storage; cranes for heavy, infrequent lifts. Materials handling is often 20–50% of manufacturing cost, which makes it a strong justification metric.
Traps
Using the wrong distance metric; ignoring return and empty trips; treating layout as pure geometry while ignoring utilities, safety clearances, and expansion; confusing a construction algorithm with an improvement algorithm.
Worked example
100 loads/day over 150 ft plus 40 loads/day over 300 ft gives 15,000 + 12,000 = 27,000 load-ft/day. Swap the department assignments, recompute, and keep the lower score.