23-Ind-A2 Analysis and Design of Work · May 2017
Nivaar worked solution (AI-drafted; not reviewed by a licensed engineer)
National Exams — May 2017 — 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 prints Question 3's second and third sub-parts both labelled “(iii)”; they are answered here in the marking-scheme order (i)/(ii)/(iii), 8/6/6 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.
Advantages of predetermined motion-time systems (PMTS, e.g. MTM): (1) they eliminate subjective performance rating entirely, since every motion’s time comes from a published table derived once from a large independent film study, removing the analyst-to-analyst inconsistency (and the “rating creep” toward looseness) that plagues purely stopwatch-rated standards; (2) a standard can be set before the job is physically running — useful for cost estimating, quoting, and capital-equipment justification on a job that does not yet exist on the shop floor; (3) building the standard forces an unusually detailed methods analysis as a byproduct, since every motion must be individually identified and classified, which itself often surfaces inefficiencies a stopwatch study would miss; (4) results are highly consistent between different analysts, and even between different companies using the same system; and (5) they remain usable on very short-cycle elements too brief to time accurately with a stopwatch.
Disadvantages: (1) applying a detailed PMTS correctly requires extensive analyst training and is itself time-consuming, especially at the fine motion-by-motion level of MTM; (2) PMTS is poorly suited to highly variable, non-repetitive or very long-cycle work, where the sheer volume of motions to classify becomes impractical; (3) machine-controlled or automatic elements (e.g. the power-feed drilling of Question 4(i)) still cannot be timed by a body-motion system and must be measured directly; (4) there is an up-front cost to acquire, learn and maintain the system; and (5) unusual physical characteristics of a specific plant, tooling, or individual worker may not be fully captured by tables built from a general, historical sample of operators, requiring case-by-case judgement about applicability.
Put in plain terms for someone on the floor who has never heard of it: “MTM is a way of working out how long a job should take without anyone standing over you with a stopwatch. Years ago, industrial engineers filmed many different experienced people doing all kinds of hand work, frame by frame, and measured exactly how long basic motions take — reaching for something, picking it up, moving it across, turning it, letting go of it, and so on. It turns out almost every job, no matter how new or unusual it looks, is really just those same few basic motions strung together and repeated. So instead of timing YOU personally, the engineer breaks your job down into that same short list of motions, looks up the standard time for each one from a published table, and adds them up to get the time for the whole job. That means the number doesn’t depend on whether you happened to be having a fast day or a slow day when someone was watching — a different worker doing exactly the same motions on exactly the same job would get the same standard. It also means the time for a new job can be worked out on paper before the line is even running, so everyone starts with a fair, already-checked number from day one instead of waiting for a stopwatch study after the fact.”
MTM assigns a time value (in Time Measurement Units, $1\ \text{TMU}=0.0006\ \text{min}$) to every Reach (R, the hand moves empty to a destination) and every Move (M, the hand moves an object to a destination) based on a small set of governing factors rather than distance alone:
Reach. (1) distance moved — longer reaches take more time, though not in direct proportion (there is a fixed component plus a distance-dependent component); (2) the type of reach (case) — Case A: to an object in a fixed location, or to an object in the other hand (fastest, most certain); Case B: to a single object whose location varies slightly cycle to cycle; Case C: to an object mixed with other objects, requiring search and selection before the reach is complete; Case D: to a very small object requiring an accurate, precise grasp; and Case E: an indefinite reach used only to reposition the hand or move the body into balance, with no actual object to grasp; and (3) whether the destination location is known and can be reached without conscious searching, which is really the practical distinction underlying cases A/B versus C.
Move. (1) distance moved, again with a fixed plus distance-dependent time component; (2) the type of move (case) — Case A: object moved to the other hand or against a stop (least care required); Case B: object moved to an approximate or indefinite location; Case C: object moved to an exact location, requiring extra care and time to position it correctly; and (3) the weight (or resistance) of the object being moved — MTM adds a dynamic weight factor to the base move time once the object exceeds a small threshold weight, since a heavier object requires additional muscular effort and control throughout the move, unlike Reach (an empty hand), which is unaffected by any object weight.
