23-Ind-A3 Facilities Planning · May 2013
Nivaar worked solution (AI-drafted; not reviewed by a licensed engineer)
National Exams — May 2013 — 98-Ind-A3 Facilities Planning. Three-hour, closed-book exam (Casio or Sharp approved calculator only); any five of the seven questions constitute a complete paper and only the first five answered in the answer book are marked — all seven are solved below for completeness.
Reference texts: Tompkins, White, Bozer & Tanchoco, Facilities Planning (4th ed., Wiley) — facilities-planning objectives, material flow, activity relationships, layout types, material handling systems, computerized layout (CRAFT/CORELAP), and tool-crib centralization; Niebel & Freivalds, Niebel’s Methods, Standards, and Work Design (13th ed.) — assembly-line balancing (Ranked Positional Weight technique), buffer/decoupling design, and operator-paced line speed.
Question text not reproduced: the examination questions are © Engineers and Geoscientists BC. Open the official past paper (linked at the top of this page) to read the question, then follow the worked solution below.
Material handling system design follows the same logic as the material-flow planning questions in Question 1(ii), carried through to a concrete equipment/method solution: (1) define the objective and scope — what material handling must accomplish (throughput, service level, cost target) and over what part of the facility; (2) analyze the material — physical/chemical characteristics, unit-load potential, quantity and value; (3) analyze the move — the from–to flow pattern, frequency, distance and any timing constraints, typically captured on a from–to chart; (4) analyze the method — generate alternative handling methods/equipment consistent with the unit-load principle, then screen them against the material and move analysis; (5) identify feasible alternatives that satisfy the technical requirements; (6) evaluate the alternatives against cost (capital and operating), flexibility, and the layout constraints established in Question 2(ii); (7) select the preferred handling method/equipment; and (8) implement, and audit performance against the original objective, feeding back into the next planning cycle (Question 1(i)) since material handling requirements evolve as product/volume changes. This sequence mirrors, and is deliberately integrated with, the overall facilities-planning and layout process, because handling and layout decisions are interdependent, not separable.
A well-designed shipping/receiving plan should provide: (1) sufficient dock capacity and door count sized to the peak (not just average) truck/rail arrival rate, avoiding vehicle queuing that wastes carrier and dock time; (2) adequate maneuvering and staging area both outside (truck apron/turning radius) and inside (staging lanes for incoming/outgoing unit loads) so vehicles and material handling equipment are not congested; (3) a clear, one-directional flow from receiving through inspection/staging to storage (and the mirror-image path from storage through staging to shipping), avoiding crossing traffic between inbound and outbound material; (4) separation of receiving and shipping where volume justifies it (separate docks/areas), reducing the chance of receiving and shipping traffic interfering with each other, though a combined dock can be appropriate at lower volumes; (5) appropriate dock equipment — levelers, seals/shelters, and dock configuration (straight-in, sawtooth/finger docks) matched to the vehicle types served; (6) space and process for verification activities — receiving inspection, counting, and put-away staging on the inbound side; order verification, packing and load-building staging on the outbound side; (7) flexibility to accommodate different vehicle sizes, seasonal volume peaks, and changing carrier mix without reconfiguring the dock; and (8) integration with the internal material handling and storage system, so travel distance from dock to storage (and storage to dock) is minimized — shipping/receiving is not a standalone function but the two end-points of the overall facility flow pattern (Question 5(iii)(b)).
Powered (live) roller conveyors move unit loads (cartons, pallets, totes) along a fixed path on a series of motor-driven rollers, providing continuous or accumulating (zero-pressure) transport without requiring the load to be self-propelled or manually pushed. Characteristics: fixed path (low routing flexibility once installed); high, consistent throughput for standardized unit loads travelling a repetitive route; capable of accumulation (loads can queue on the conveyor itself, which is a form of the in-line buffering discussed in Question 3(ii)); relatively high fixed capital cost and floor-space commitment, but low incremental operating cost per unit moved once installed; well suited to point-to-point transport between fixed stations (as in an assembly or process line) rather than to variable, on-demand moves.
A bridge (overhead travelling) crane spans an area on rails mounted high on the building structure or on dedicated runway columns, with a hoist/trolley that travels along the bridge, giving three-axis (bridge travel, trolley travel, hoist lift) coverage of the entire area beneath the crane without consuming any floor space for its own travel path. Characteristics: very high lifting capacity, suited to heavy, bulky loads that floor-level equipment cannot handle economically; covers a large rectangular service area with a single piece of equipment; does not obstruct floor-level traffic or storage since it operates entirely overhead; requires significant building structural capacity (runway beams/columns sized for the crane and maximum load) that must be planned into the building design from the outset, not retrofitted cheaply; and, being a single shared resource over its service area, can become a bottleneck if multiple work areas beneath it compete for crane time simultaneously.
An industrial robot is a reprogrammable, multi-axis manipulator used to perform handling, assembly, welding, painting or other repetitive tasks under program control rather than fixed mechanical linkage. Characteristics: highly flexible/reprogrammable — the same physical robot can be re-tasked for a different product or operation sequence by changing its program and end-effector (tooling), unlike single-purpose fixed automation; capable of high precision and repeatability, and of working continuously (including in hazardous, high-heat, or otherwise unsafe-for-humans environments); higher capital cost and more sophisticated integration/programming/maintenance requirement than either powered conveyors or manual handling; economically justified primarily where volume is high enough and/or the task is hazardous/precision-critical enough to offset the capital and integration cost; commonly used within manufacturing cells (Question 5(i)) for load/unload, assembly and welding operations where its flexibility across the cell's part family is a direct advantage over single-purpose fixed automation.
