23-Ind-A4 Production Management · December 2019
Nivaar worked solution (AI-drafted; not reviewed by a licensed engineer)
National Technical Examinations — December 2019 — 17-Ind-A4 Production Management. Three-hour, closed-book exam; Casio or Sharp approved calculators only. Format: seven questions, each worth 20 marks (sub-part weights per the front-page marking scheme); candidates do two questions from Section A and three from Section B, and only the first five questions appearing in the answer book are marked. All seven are solved below for completeness. The paper asks for point-form answers wherever possible; the solutions below use full working for clarity.
Reference texts: Liker, The Toyota Way, and Shingo, A Revolution in Manufacturing: The SMED System — JIT, 5S/andon/poka-yoke/SMED/TPM and lean root-cause analysis; Niebel & Freivalds, Methods, Standards, and Work Design — process charting and methods analysis; Nahmias & Olsen, Production and Operations Analysis (7th ed., Waveland/McGraw-Hill) — forecasting, lot sizing (Wagner–Whitin) and aggregate planning; Hillier & Lieberman, Introduction to Operations Research (11th ed.) — project scheduling (CPM/PERT); Pinedo, Scheduling: Theory, Algorithms, and Systems (5th ed.) — parallel-machine scheduling and days-off workforce scheduling.
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.
Yo-i-don ("ready–set–go") is a line-balancing technique in which all operators on a manual assembly line begin their cycle simultaneously at a common start signal; because everyone starts at the same instant, the supervisor can see at a glance, without a stopwatch, which operators finish early (and are under-loaded) and which fall behind (and are over-loaded), and rebalance work content between stations accordingly. Andon is the companion visual-control device: a light, board or cord-pull that any operator activates the moment an abnormality (a defect, a stockout, a stopped machine) occurs, immediately signalling the location and nature of the problem to supervisors and support staff so a response is triggered in real time rather than discovered on the next walk-through or at end-of-shift. Together, both tools make the true state of the line — who is behind, and what has gone wrong — visible the instant it happens, which is the precondition for jidoka (stopping and fixing problems at their source) rather than letting them propagate silently downstream.
Poka-yoke ("mistake-proofing," literally "avoiding inadvertent errors") is a physical device, fixture, or process design feature that makes it impossible, or immediately and unmistakably obvious, to perform an operation incorrectly. It works either by prevention — a part or fixture is shaped so a component can only be inserted in the correct orientation (an asymmetric locating pin, a keyed connector) — or by detection — a sensor or counter that halts the line or sounds an alarm the instant a required step is skipped or a wrong count is picked (a light curtain that confirms every bin position was reached before a kit is released). Because it removes the possibility of the error at the point of occurrence rather than relying on downstream inspection or operator vigilance, poka-yoke is generally far cheaper and more reliable than after-the-fact quality control.
SMED (Single-Minute Exchange of Die), developed by Shigeo Shingo, is a structured methodology for reducing equipment changeover/setup time, ideally to below ten minutes (a "single digit" number of minutes). Its core technique is separating setup work into internal steps (which can only be done while the machine is stopped, e.g. removing the old die) and external steps (which can be done while the machine is still running the previous job, e.g. staging the new die and tools nearby); converting as many internal steps to external as possible, and then simplifying and parallelizing whatever internal work remains (standardized fasteners, guide pins instead of bolts requiring adjustment, dedicated setup carts), drives the changeover time down sharply. Fast, reliable changeovers are what make small-lot, JIT-style production economically viable, since they remove the large fixed cost that would otherwise force large batch sizes.
TPM (Total Productive Maintenance) is a maintenance philosophy that shifts routine equipment care — cleaning, lubricating, inspecting, minor adjustment — from a separate maintenance department onto the machine's own operators (autonomous maintenance), freeing skilled maintenance staff to focus on more technical preventive and predictive work, and engaging the people closest to the equipment in noticing early signs of deterioration before they cause a breakdown. Its aim is to maximize Overall Equipment Effectiveness (OEE $=$ Availability $\times$ Performance $\times$ Quality) by systematically attacking the "six big losses" (breakdowns, setup/adjustment, idling/minor stops, reduced speed, startup defects, process defects) rather than treating unplanned downtime as an unavoidable cost of doing business.
