Cost-benefit analysis for disruption prevention in low-volume assembly

Manufacturing companies face rising pressure due to increased competition. Traditionally, companies have merely concentrated on offering impeccable, cost-efficient products. Today, however, flexibility and on-time delivery are additional requirements to satisfy the customers. At the same time, disruptions in production, especially in low-volume assembly, still frequently occur, leading to economic losses and delayed customer deliveries. The approach proposed in this paper strives for improving the disruption situation in low-volume assemblies. A detailed disruption management methodology has been developed, aiming at realizing an efficient reduction of disruptions, while at the same time considering the specific characteristics of low-volume assembly. The methodology is supported by a catalog of pre-emptive measures. These measures are known to reduce the disruptions’ occurrence or to diminish their consequences. In general, the approach pursues the basic idea to implement particularly those measures, which have the best cost-benefit-ratio. Based on the analysis of the cost-benefit-ratio of each measure, the developed methodology aims at improving the disruption situation in assembly and thus providing a high on-time delivery rate. The usability of the methodology for the low-volume assembly context has been confirmed by assembly experts on the basis of an application of the methodology in an exemplary case study.     

The effect of slightly warm temperature on work performance and comfort in open‐plan offices – a laboratory study

The aim of the study was to determine the effect of a temperature of 29°C on performance in tasks involving different cognitive demands and to assess the effect on perceived performance, subjective workload, thermal comfort, perceived working conditions, cognitive fatigue, and somatic symptoms in a laboratory with realistic office environment. A comparison was made with a temperature of 23°C. Performance was measured on the basis of six different tasks that reflect different stages of cognitive performance. Thirty‐three students participated in the experiment. The exposure time was 3.5 h in both thermal conditions. Performance was negatively affected by slightly warm temperature in the N‐back working memory task. Temperature had no effect on performance in other tasks focusing on psychomotor, working memory, attention, or long‐term memory capabilities. Temperature had no effect on perceived performance. However, slightly warm temperature caused concentration difficulties. Throat symptoms were found to increase over time at 29°C, but no temporal change was seen at 23°C. No effect of temperature on other symptoms was found. As expected, the differences in thermal comfort were significant. Women perceived a temperature of 23°C colder than men.     

Getting to grips with automated prepreg handling

Automated manufacturing of composite parts based on prepreg material is receiving increased interest with the rising use of composite materials for high-performance applications. The two main automation alternatives for prepreg layup, automated tape layup and fiber placement, are not cost-effective for all types of products, and manual labor is common for the manufacturing of complex parts in low manufacturing volumes. Alternatives to the two dominant automation solutions have been pursued, but so far these have had a limited impact in industrial applications. This paper presents four different solutions for automated layup of prepreg plies to flat laminates that can be formed in a subsequent forming process, which decrease the system complexity. The solutions target products where the layup of flat laminates today is done manually due to technical limitations or cost considerations. The layup solutions must manage challenges caused by material properties such as low material rigidity and tack, and be able to handle a high number of ply shapes. All four solutions are designed for prepreg that is covered with a stiff backing paper. The aim of the paper is to analyze and compare the four solutions. It can be concluded that the most versatile solution is a dual-arm robot equipped with simple end effectors. The dual-arm solution presents a possibility to control the pick-up and lay-down motions that make peeling motions possible, which is advantageous when picking material that has tacked to the pickup surface.     

A review of motion planning algorithms for intelligent robots

Journal of Intelligent Manufacturing - Principles of typical motion planning algorithms are investigated and analyzed in this paper. These algorithms include traditional planning algorithms,...     

Beyond economics—understanding the decision-making of German small private landlords in terms of energy efficiency investment

The German government aims to achieve virtually climate-neutral building stock by 2050 to tackle climate change. To realise this goal, comprehensive policy packages based on neoclassical economic theory are in place to foster energy efficiency investment. However, in the building sector, there is increasingly a gap between this aspiration and the reality. It is claimed that one of the main reasons for this is that the existing policy framework fails to address the specific characteristics and needs of different groups of building owners. This is a particular challenge in Germany, where 80% of all dwellings are owned privately and 37% are rented out by small private landlords (SPL). Despite the significant numbers of SPL, they often follow black box decision-making processes when considering energy renovations. In this study, the author uses an explanatory model to understand the decision-making processes of SPL, combining theoretical aspects from different research disciplines. This model was applied to a low-demand housing market in a neighbourhood in the Ruhr area. Eighteen semi-structured interviews (each lasting between 37 and 115 min) were conducted, demonstrating that in addition to economic factors, the values, beliefs, norms and routines of SPL—as well as their personal capabilities and contextual factors—play an important role in their decision-making. Based on the findings, recommendations are made for enhancing the effectiveness of existing energy efficiency policies and other supporting instruments (e.g. tenancy law and social legislation), tailored to the specific needs of SPL.