Rabindra Nath Sen’s research while affiliated with Multimedia University and other places

The study is aimed at improving productivity and quality, increasing revenue and reducing rejection cost of the manual component insertion (MCI) lines in a printed circuit assembly (PCA) factory. Subjective assessment (through questionnaire), direct observation method, and archival data were used. Live experiments were conducted on production lines. Eleven problems were identified, i.e., long search for materials from the stores, unproductive manual component counting, obstructions during insertions, component fall-off while the PCA board was traveling on a U-shaped conveyor, etc. Interventions were made to rectify the problems, i.e., to have only one central store to eliminate confusion of the materials’ whereabouts, use weighing scale for component counting, modify the MCI sequence and the bin arrangements to avoid obstructions, and use straight conveyor to reduce handling. As a result, there was a tremendous increase in productivity and yearly revenue (US$4,223,736) and a huge reduction in defects and yearly rejection costs (US$956,136).

An ergonomics improvement study was conducted on the visual inspection process of a printed circuit assembly (PCA) factory. The process was studied through subjective assessment and direct observation. Three problems were identified: operators' eye problems, insufficient time for inspection and ineffective visual inspection. These problems caused a huge yearly rejection cost of US 298,240 dollars, poor quality, customer dissatisfaction and poor occupational health and safety. Ergonomics interventions were made to rectify the problems: reduced usage of a magnifying glass, the use of less glaring inspection templates, inspection of only electrically non-tested components and introduction of a visual inspection sequence. The interventions produced savings in rejection cost, reduced operators' eye strain, headaches and watery eyes, lowered the defect percentage at customers' sites and increased the factory's productivity and customer satisfaction.

A case study to illustrate the cost effectiveness of ergonomic redesign of electronic motherboard was presented. The factory was running at a loss due to the high costs of rejects and poor quality and productivity. Subjective assessments and direct observations were made on the factory. Investigation revealed that due to motherboard design errors, the machine had difficulty in placing integrated circuits onto the pads, the operators had much difficulty in manual soldering certain components and much unproductive manual cleaning (MC) was required. Consequently, there were high rejects and occupational health and safety (OHS) problems, such as, boredom and work discomfort. Also, much labour and machine costs were spent on repairs. The motherboard was redesigned to correct the design errors, to allow more components to be machine soldered and to reduce MC. This eliminated rejects, reduced repairs, saved US dollars 581495/year and improved operators' OHS. The customer also saved US dollars 142105/year on loss of business.

An ergonomic study was conducted to improve the workstations for electrical tests in a printed circuit assembly (PCA) factory in an industrially developing country (IDC). Subjective assessment and direct observation methods were used on the operators to discover the problems in their workstations. The problems found were: (i) poor workstation design, (ii) mix-up of tested and untested boards, (iii) missing or incorrect test steps, and (iv) unclear pass/fail colour inspection criteria. Ergonomic interventions implemented were: (i) an improved workstation with space for resting arms and the oscilloscope and computer keyboards within easy reach of the operators; (ii) clear segregation of tested and untested boards to prevent mix-up; (iii) retraining of operators by more qualified trainers; and (iv) reference colour samples for more effective recognition of different colours in the projection screen. The results were average savings in yearly rejection cost (of US$574,560), reduction in rejection rate, increase in monthly revenue, improvements in productivity, quality, operators’ working conditions and occupational health and safety (OHS) and enhancement in customers’ satisfaction. The cost of the interventions was less than US$1100. The interventions implemented were simple and inexpensive but resulted in many benefits.Relevance to industryThe study will be beneficial, if repeated in other PCA or electronic factories in IDCs, in terms of improvements in quality, productivity and OHS of the workers, as most of them have similar manufacturing processes and equipment and poor awareness in ergonomics.

The study aimed at reducing the occupational health and safety problems faced by the manual component insertion operators. Subjective and objective assessments, and direct observations were made in the printed circuit assembly factory. Simple and low-cost ergonomic interventions were implemented, that is, repairing chairs, reducing high workloads, assigning operators to a maximum of 2 workstations, confining machines that emitted bad smell and much noise, and providing finger work aids. The results of the interventions were reductions in operators' work discomforts, that is, chair discomfort (by 90%), high work stress, and discomfort due to profound change in their workstations. Their health hazards were also eliminated, that is, inhalation of toxic fumes, exposure to too much noise, and pain due to pressing sharp components.

A survey was conducted on the efficacy of the Printed Circuit Assembly operations using newly designed Ergonomic Weighted Scores (EWSs) to evaluate Critical Instructions (CIs) to operators. This helped to choose priorities of problematic operations. Five EWSs were drafted, tried, and finalized by a team of experts, for the purpose of checking the adherence to CIs, failing any of which could cause adverse effects on the quality of products. The top three priority operations were identified and the follow-up studies resulted in an increase in monthly revenue of US$227,880 and improvements in quality, productivity, occupational health and safety of the operators. © 2003 Wiley Periodicals, Inc. Hum Factors Man 13: 41–58, 2003.

The present study aimed at investigating user's preferences for public payphones and addressed some of the issues associated with extra services, comfort and satisfaction levels or user-friendliness on the existing features and ergonomic design of public payphone. The study also looked into the merits and demerits of the existing payphone facilities.

Workstations for Visual Inspections (WVIs) and also for Electrical Tests (WETs) of a multimedia product factory were studied from Ergonomic viewpoints. The problems, identified by subjective assessments and direct observations, were related to poor designs of workstations, work processes and improper tools, causing high (12.2 ± 4.1%) product returns. In some WVIs, operators were having visual fatigue due to excessive magnifying glass usage, glare from inspection templates and too many components to check within a very short period. Some WETs were not organised to reduce hands and body motions, and to eliminate confusing criteria for passing or failing of the tests. They also had poor visual projection tests due to too bright ambient illumination on the screen. The Ergonomic improvements were: the reduced usage of magnifying glass, the use of no-glare templates, visual inspection of only the electrically non-tested components, the re-design of WETs for economy of motion, the improvement on pass or fail criteria, dark space for effective visual projection tests, etc. These ergonomic interventions improved the company's productivity and operators' health, reduced the product returns and saved USD 70,900 per month.