23-Ind-A2 Analysis and Design of Work · May 2018
Nivaar worked solution (AI-drafted; not reviewed by a licensed engineer)
National Exams — May 2018 — 98-Ind-A2 Analysis and Design of Work. Three-hour, closed-book exam (approved Casio/Sharp 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. The source’s marking-scheme line for Question 3 mislabels its final sub-part “(ii)” a second time instead of “(iii)”; it is answered here in the natural (i)/(ii)/(iii) order that matches the question text itself, 5/5/10 marks.
Reference texts: Niebel & Freivalds, Niebel’s Methods, Standards, and Work Design (13th ed.) — operations analysis, workplace/tool design and motion economy, stopwatch time study, performance rating and allowances, predetermined time systems (MTM/MOST), work sampling, wage-incentive and job-evaluation systems.
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.
Motion economy classifies every hand/arm motion by which body members it sets in motion, from the smallest, fastest-moving mass to the largest. Five classes are recognized, each nested inside the next: Class 1 — fingers only (pivoting at the knuckle); Class 2 — fingers and wrist; Class 3 — fingers, wrist and forearm (pivoting at the elbow); Class 4 — fingers, wrist, forearm and upper arm (pivoting at the shoulder); Class 5 — the entire arm plus a twist of the trunk/shoulder girdle. Each higher class recruits a larger, heavier body segment, and moving a heavier segment through the same distance takes measurably longer and consumes more muscular energy than moving a lighter one — a Class 1 finger flick is both faster and less fatiguing than a Class 5 reach-and-twist covering the same working distance.
The operator should therefore be trained, and the workplace laid out, so that every motion is performed at the lowest classification that the task genuinely requires: bring materials and controls within finger/wrist reach rather than forcing a full-arm reach, use fixtures that let the hand pivot at the wrist instead of walking the whole forearm across the bench, and eliminate any motion class higher than the job truly needs. The direct payoff is a shorter, less fatiguing cycle: less time is spent moving mass, less muscular effort is expended per cycle, and because the smaller classes involve less momentum they are also easier to perform accurately and safely at a sustained pace across a full shift.
Operations analysis is the systematic, element-by-element examination of every operation in a process with the single aim of eliminating unnecessary work and finding a better way to perform the work that remains. It is applied after the process is charted (Question 1(iii)) and before a method is standardized: the analyst questions the purpose, design, materials, sequence, tooling, handling, layout and working conditions of each operation, challenging “why is this done, why this way, why by this person, why here, why now” for every step, rather than accepting the existing method as fixed.
The primary approaches (lines of questioning) used to conduct operations analysis are: (1) the purpose of the operation — can it be eliminated, combined with another, or simplified; (2) design of the part — can tolerances, finish or configuration be relaxed without harming function; (3) tolerances and specifications — are they realistic for the process and the need, or needlessly tight; (4) materials — is a cheaper, more workable, or more available material acceptable; (5) manufacturing sequence and process — is this the most economical process and operation order (Question 2(iii)); (6) setup and tools — are jigs, fixtures and tooling appropriate and efficient (Question 2(iii)); (7) materials handling — can moves, delays and re-handling be reduced; (8) plant layout — does the physical arrangement minimize travel and backtracking; and (9) working conditions — do lighting, ventilation, noise and safety support sustained performance (Question 2(i)).
Operations analysis is used to reveal, quantify and prioritize opportunities for improvement across an entire process before any single workstation is redesigned in detail — it shows management where operations, inspections, delays, transports and storages actually occur, how many of each, and how much time and distance they consume, so that engineering effort is spent where the payoff is largest rather than on whichever station happens to be visible.
The operation process chart is the highest-level of the standard process-charting symbols: it records only the two symbols that add value or verify quality — a small circle for an operation (a change in the physical or chemical characteristics of an object, or an assembly/disassembly step) and a small square for an inspection (a check of quality or quantity against a standard) — deliberately omitting transports, delays and storages, which belong to the more detailed flow-process chart. Each symbol is numbered sequentially in the order performed, component parts are shown entering the main vertical line from the right on their own short horizontal branches at the point they join the assembly, and every symbol carries the time (and where relevant the material) associated with it. The chart closes with a summary tabulating the total number of operations and inspections and the total time for each, giving a single-page overview of the whole process that operations analysis then works from.
