Challenges and trends in the allocation of the workforce in manufacturing shop floors

In variable manual assembly production of highly customised products, effective allocation of workers to products is required. To support decision making here, industrial managers should be aware of the performance effects of the number of workers and learning within individual products. Evidence on such fundamental effects requires laboratory studies with products similar to those in real assembly industries. Because of the lack of such studies, this paper studies experimentally the effects of group size (one to four workers) and learning (up to four repetitions per group) on the performance of product assembly. The product, built for the purpose of the present study, consists of representative elements from real products in the mechanical engineering industry. A total of 68 undergraduate students participated in the experiments. The results from the experiments are in line with the hypotheses that the mean assembly time decreases at a decelerating rate as a function of both group size and repetitions, and that productivity per worker decreases as a function of group size. The results are explained in more detail through the experiences of the participants. Managerial implications and aspects for future research are also discussed.

Section: Managerial Implications and Limitations Of The Researchmentioning

confidence: 99%

“…While assembly production faces variation as a result of e.g. volatile customer demand and differences between workers (Buzacott 2013), the ability to match the current capacity of the workforce with the floor-level processes is becoming increasingly important (Ruiz-Torres and Mahmoodi 2007;Saadat et al 2013). In order to e.g.…”

Section: Introductionmentioning

confidence: 99%

Effects of group size and learning on manual assembly performance: an experimental study

Peltokorpi

Niemi

2018

“…Corominas, Olivella, and Pastor (2010) considered the problem of assigning and scheduling a set of tasks to a set of workers, according to which worker's performance for a given task depends on the worker experience. Recently, Saadat et al (2013) presented an overview of a recent study in the application of the principles of holonic manufacturing systems, as an example of intelligent system approach to develop a flexible workforce allocation model. An interesting case study that confirms the beneficial impact of staff planning in cost reduction was proposed by Hemig, Rieck, and Zimmermann (forthcoming), who modelled by a non-linear mixed integer programming, and solved by dynamic programming, a real manufacturing system based on parallel assembly lines.…”

Section: Introductionmentioning

confidence: 99%

Joint optimization of a flow-shop group scheduling with sequence dependent set-up times and skilled workforce assignment

Costa

Cappadonna

Fichera

2014

Flow-shop sequence-dependent group scheduling (FSDGS) problem has been extensively investigated in the literature also due to many manufacturers who implemented the concept of group technology to reduce set-up costs, lead times, work-in-process inventory costs, and material handling costs. On the other hand, skilled workforce assignment (SWA) to machines of a given shop floor may represent a key issue for enhancing the performance of a manufacturing system. As the body of literature addressing the group scheduling problems ignored up to now the effect of human factor on the performance of serial manufacturing systems, the present paper moves in that direction. In particular, an M-machine flow-shop group scheduling problem with sequence-dependent set-up times integrated with the worker allocation issue has been studied with reference to the makespan minimization objective. First, a Mixed Integer Linear Programming model of the proposed problem is reported. Then, a well-known benchmark arisen from the literature is adopted to carry out an extensive comparison campaign among three properly developed metaheuristics based on a genetic algorithm framework. Once the best procedure among those tested is selected, it is compared with an effective optimization procedure recently proposed in the field of FSDGS problems, being this latter properly adapted to run the SWA issue. Finally, a further analysis dealing with the trade-off between manpower cost and makespan improvement is proposed.

“…stated that a worker coordination policy 'allocates workers to tasks (or tasks to workers) over time'. Several earlier studies examined worker coordination policies to show how they influence system performance (see the paper of Saadat et al, 2013, in which challenges and trends concerning workforce allocation are reviewed). Since in production systems workers are typically specialised in one task of one station, workforce flexibility and coordination between the stations are based on cross-training that enables workers to perform multiple task types.…”

Section: Literature Reviewmentioning

confidence: 99%

Worker coordination policies in parallel station systems: performance models for a set of jobs and for continuous arrival of jobs

Peltokorpi

Tokola

Niemi

2014

Worker coordination policies in parallel station systems: performance models for a set of jobs and for continuous arrival of jobs Varying workloads and uncertain processing times in parallel assembly cause idle times for skilled, high-cost workers. This idleness can be avoided and the utilisation of the workers improved by allowing workers to move between the stations to help each other. Worker movement between assembly stations needs efficient and feasible coordination, and therefore, this paper compares four different worker coordination policies: no helping, floater, pairs and complete helping. The dynamics of the policies are modelled by studying the parallel assembly as a continuous-time Markov process. The system is studied with two different job release cases for non-identical jobs (customised products). In the first case, a given number of jobs have to be completed by the entire system. In the second case, new jobs arrive with a Poisson-distributed rate. The models assume that when one worker helps another, their collaborative inefficiency reduces the productivity. The models are used in numerical experiments to compare the performances of worker coordination policies as average job cycle times. The main conclusions from the results suggest the use of the complete helping policy in minor collaborative inefficiency conditions, especially with a given set of jobs. The pairs policy is a reasonable alternative in major inefficiency conditions with the continuous arrival of jobs.