Evaluación del sistema de mantenimiento de la máquina de inyección de plástico mediante el método TOPSIS

The following document talks about the parameters of the maintenance system implemented in plastic injection machines of a maquiladora company located in Ciudad Juarez Chihuahua. The method used in this investigation is essentially ulti-criteria decision making, the technique for the order of preference for similarity to the ideal TOPSIS solution. Therefore, an evaluation of the maintenance system is carried out, using measurable collected in said company. With this evaluation the plastic injection machine is determined in better conditions, as well as the machine in worse conditions, which helps management to make better decisions regarding each machine. The objective of this research is to address the study of decision-making in the industrial field specifically in the maintenance system of plastic injection molding machines.El siguiente documento habla sobre los parámetros del sistema de mantenimiento implementado en las máquinas de inyección de plástico de una empresa maquiladora ubicada en Ciudad Juárez Chihuahua. El método utilizado en esta investigación es esencialmente la toma de decisiones multicriterio,  la  técnica  para  el  orden  de  preferencia  por  la  similitud  con  la  solución  ideal  de  TOPSIS.  Por  lo  tanto,  se  realiza  una  evaluación  del  sistema  de  mantenimiento,  utilizando datos medibles recogidos en dicha empresa. Con esta evaluación se determina la máquina de inyección de plástico en mejores condiciones, así como la máquina en peores condiciones, lo que ayuda a la dirección a tomar mejores decisiones respecto a cada máquina. El objetivo de esta investigación es abordar el estudio de la toma de decisiones en el campo industrial específicamente en  el  sistema  de  mantenimiento  de  las  máquinas  de  moldeo  por  inyección  de  plástic

Delay-time modelling of a critical system subject to random inspections

We model the inspection-maintenance of a critical system in which the execution of inspections is random. The models we develop are interesting because they mimic realities in which production is prioritised over maintenance, so that inspections might be impeded or they might be opportunistic. Random maintenance has been modelled by others but there is little in the literature that relates to inspection of a critical system. We suppose that the critical system can be good, defective or failed, and that failure impacts on production, so that a failure is immediately revealed, but a defect does not. A defect, if revealed at inspection, is a trigger for replacement. We compare the cost and reliability of random inspections with scheduled periodic inspections and discuss the implications for practice. Our results indicate that inspections that are performed opportunistically rather than scheduled periodically may offer an economic advantage provided opportunities are sufficiently frequent and convenient. A hybrid inspection and replacement policy, with inspections subject to impediments, is robust to departure from its inspection schedule. Keywords: Maintenance; reliability; random inspection; production; qualit