An economic-statistical production quantity model under quality-maintenance policy for imperfect manufacturing systems with interaction effect among assignable causes

Abstract

This study integrates production and maintenance planning with statistical process monitoring in the presence of dependent multiple assignable causes. To adapt the model to the reality, two assumptions are considered: (1) the assignable causes (ACs) are dependent, and (2) the occurrence of ACs can affect both process mean and variability. Given the second assumption, a non-central chi-square (NCS) chart is used to monitor the process. Since the occurrence rate of ACs increases over time, a non-uniform sampling scheme is presented to reduce the out-of-control time period. A sensitivity analysis is presented to explore how the number of AC types influences the cost terms. The results indicate that the more AC types, the higher quality loss and maintenance costs are imposed on the manufacturer. Moreover, three comparative studies are conducted for confirming the effectiveness of the model. The first comparative study shows that the total cost will be less than its real value when the interdependency among the ACs is ignored. The second comparison shows that the NCS chart outperforms the XR  in detecting the process disturbances and leads to a less quality loss cost. Eventually, the last one represents that employing the non-uniform sampling strategy leads to a significant cost savings.

Integrated maintenance, inventory and quality engineering decisions for multi-product systems

“…Salmasnia et al (2019b) studied the ESD of an adaptive non-central chi-square control chart considering production planning and maintenance scheduling. Salmasnia et al (2022) Considering a multi-product system, the present article study presents a hybrid mathematical formulation to optimise the expected total production cost unit (ETCU) during each cycle. The proposed model involves the inventory cost, including holding and ordering costs, corrective and preventive maintenance costs, as well as sampling and quality control costs.…”

Demand-supply planning and sustainability aspect for agro-based perishables in cold-chain

“…Further, analysing the sustainability aspect for perishables is also very important due to their limited holding life, considering their effect on three main aspects, i.e., economic, environment and social aspect (Saravi et al, 2019), as discussed in Table 6 and Table 7 of this research paper. Inventory control, quality control, and maintenance are three interrelated operational factors affecting the performance of manufacturing systems (Salmasnia et al, 2019). The risks that threaten supply chains and can greatly affect their performance are the existing uncertainties in the environment, including uncertainties in supply, demand, and costs and disruptions caused by natural and man-made disasters such as floods, earthquakes, storms, political unrest, strikes, etc.…”