Economic Production Quantity Model Research Articles

A sustainable fuzzy economic production quantity model (SFEPQM) with sporadic machine failures, inspection and prepayments under carbon tax and cap policy

Goals for sustainability have caused an upcoming change in the emphasis of Economic Production Quantity models, which was previously limited mainly to financial considerations to include aspects of the environment as well. The primary tools used in many nations to reduce emissions are carbon cap and price legislation. However, companies in the production industry may have difficulties with their planning and oversight procedures as they frequently have to cope with faulty products and machinery failures. Previous research has not addressed the comprehensiveness of green investment in machine breakdowns. Considering this problem, we have developed a sustainable economic production quantity model with sporadic malfunctions of machinery and prepayments under carbon tax and cap regulations. Our aim is to minimise the overall cost of faulty items with the investment in green technologies. An approach that combines with the outstanding effectiveness of green strategies to minimise emissions will culminate in a greener production that generates more profit than the traditional system. This study considers two cases i.e. with and without green technology investment (GTI). It also has many predictions, including the execution of inspections afterwards as well as during manufacturing, faulty goods are scrapped while others are sold at discounted price.

Optimized Economic Production Quantity Inventory Model with Weibull Decay, Dynamic Holding Cost Under Varied Demand Scenario and Demand Series Analysis

This paper presents a sophisticated modification of the economic production quantity (EPQ) model. It incorporates Weibull-distributed progressive deterioration, dynamic holding costs, variable demand, and strong strategies for effectively handling shortages and backlogs. Targeting products that have a short-term expiration but can still be stored for a long time without significant deterioration, the model aims to increase production quantities while lowering overall variable expenses. The extended EPQ model utilizes Maclaurin series approximations to solve ordinary differential equations, effectively capturing the dynamics of inventory under three different demand patterns. The focus of this handle’s situations when the demand for a product changes in a predictable manner over time and considers the likelihood of defective goods during the manufacturing process. This approach provides useful insights for optimizing inventory management and production planning in the manufacturing of goods that are used up or consumed. The usefulness of the model is confirmed in the study through the use of two illustrative instances. Additionally, sensitivity analysis is utilized to suggest potential areas for additional investigation.

Single-vendor single-buyer multi-product economic production quantity problem with stochastic constraints: a modified generalized elimination method

This study designs a single-buyer single-vendor multi-product Economic Production Quantity (EPQ) model to optimize the total cost in an inventory system. To do so, a Non-Linear Programming (NLP) model is developed considering a set of stochastic constraints on space or warehouse capacity, backordering cost, procurement, ordering, and obtainable budget. A modified Generalized Elimination Method (GEM) is then offered to treat the complexity of the model wherein the variables are eliminated by adding two equations. The developed method generates much more high-quality solutions compared with the classic GEM, while the number of iterations slightly increases. Three problem instances in different scales are then taken into account to assess the efficiency of the modified GEM in terms of optimality criteria. The results demonstrate that the modified GEM has an excellent performance with respect to optimal solutions, infeasibility, number of iterations, complementarity, and errors of optimality. Finally, the behavior of the objective function is analyzed against order quantity fluctuations to draw out practical implications.

An integrated economic production quantity model with shortages considering energy utilization in production and warehousing

An integrated economic production quantity model with shortages considering energy utilization in production and warehousing

Economic production quantity model with defective items, imperfect rework process, and lost sales

Economic production quantity model with defective items, imperfect rework process, and lost sales

The economic production quantity model for an imperfect production process by control chart design

The Economic Production Quantity (EPQ) plays a crucial role in the manufacturing process. The traditional EPQ model operates under the assumption that Non-Conforming (NC) items are not produced, and the process remains under control. However, real-world scenarios often involve the production of NC products, leading to process deviations. This study introduces a model that optimizes the design of a control chart to incorporate NC products into the EPQ model. The model integrates inventory and quality-related costs to minimize the expected total cost by determining EPQ, sample size, and control limit. The solution methodology employs direct search techniques to solve this problem. The sensitivity analysis results demonstrate the significant cost reduction achieved by the proposed model compared to the classical EPQ model. The numerical examples presented in the study show an average cost reduction of approximately 21 percent, highlighting the potential effectiveness of the model in cost reduction efforts.

Enhancing Economic Development through Inventory Management Optimization in Agro-based Industries in Bihar: A Comparative Study of EOQ and EPQ Models

Inventory management is crucial for optimizing operational efficiency and cost-effectiveness in agro-based industries, particularly in regions like Bihar,known for their agricultural resources. This study compares the effectiveness of two inventory management models, the Economic Order Quantity (EOQ) and Economic Production Quantity (EPQ), in addressing the unique challenges faced by Bihar's agro-based industries. Data from Taruwar Agro Industries Private Limited in Ashiyana, Patna, use to calculate EOQ and EPQ values for three product categories: Tomato Chili, Peri Peri, and Punjabi Tadka. The study employs relevant formulas to compute optimal order quantities and total inventory costs, assuming constant demand, quality, price, holding costs, and ordering costs. Both the EOQ and EPQ models offered viable approaches to inventory optimization. EOQ focused on minimizing holding and ordering costs, while EPQ integrated production-related costs to optimize production flow. The study underscored the importance of aligning inventory management strategies with operational capabilities, market demand, and financial objectives. This study contributes to advancing theoretical understanding and practical applications of inventory management in agro-based economies like Bihar. Recommendations for empirical validation, contextual adaptation, technology integration, and long-term impact assessment are provided to enhance inventory management practices. Integration of the BCG matrix into decision-making processes offers a comprehensive approach to prioritizing inventory management strategies and guiding strategic implications.

Research on an Optimal Maintenance and Inventory Model Based on Carbon Tax Policy

The equipment in a factory will gradually deteriorate during production, leading to the production of defective products. Without appropriate maintenance, the defect rate will increase over time. Consequently, the production cost will rise, the inventory quality will be affected, the profit will decrease, and the risk of carbon emissions will increase, leading to more customer complaints and damaging the corporate image. In addition to focusing on preventive maintenance to ensure the quality of products, companies should also take carbon emissions into consideration. Furthermore, the frequency of maintenance must be carefully considered, as both carbon emissions and maintenance costs will increase if the frequency is too high; conversely, if the maintenance frequency is too low or non-existent, the defect rate may increase cumulatively, or production may be suspended due to equipment failure. Therefore, this research explores preventive maintenance and inventory management issues within an imperfect production system and develops an extended economic production quantity model that incorporates defective products as well as taking carbon tax and preventive maintenance into consideration. The main purpose is to determine the optimal maintenance frequency, production, and replenishment cycle length, so as to maximize the total profit under the carbon tax policy. This study demonstrates a computing process with relatively impractical product data based on the actual business situation of a disposable diaper manufacturer. Furthermore, a sensitivity analysis is implemented to the model parameters in the proposed model. The managemental insights are illustrated based on the results of theoretical analysis to provide a reference to policy makers during decision making, hence, to secure the sustainability and green transitions of corporates. The results of this study not only help to reduce environmental impact but can also improve the competitiveness and sustainable development of enterprises.

An economic production quantity model for an imperfect production system with selling price, advertisement frequency and green-level dependent demand

An economic production quantity model for an imperfect production system with selling price, advertisement frequency and green-level dependent demand

Impact of Inspection Error of an Economic Production Quantity Model with Acceptance Sampling, Defective Items, and Rework

Abstract: In this model, the manufacturer needs to inspect and rework defective items due to the flawed manufacturing process. When checking for defective products, two types of errors, namely Type 1 error and Type 2 error, may occur at the inspection stage. If a lot of defective materials are rejected during the inspection, a non-destructive screening process separates the material into reworkable and non-defective categories. This study includes inspection rate insufficiency (IRI) and inspection rate sufficiency (IRS) based on the relationship between inspection and production rates. Rework Priority Policy (RPP) is followed in every scenario. This paper aims to minimize the inspection error and optimize the total profit. Numerical examples help demonstrate the value of this well-established model. A sensitivity analysis of this study was carried out to check its accuracy.

Economic Production Quantity Model Considering Rework of Imperfect Goods under Stock, Advertisement, Selling Price and Replacement Period-Dependent Demand

An economic production quantity (EPQ) system with an imperfect production model in which demand is affected by advertisement frequency, selling price, stock level and product replacement time is discussed in this paper. It is unavoidable to produce only perfect quality goods in a manufacturing operation due to real-life issues like labor problems, machinery faults, etc. Therefore, we consider the production system imperfect and manufacture a fraction of imperfect goods that depend on the production rate. All produced goods are continuously shifted to the screening center, where perfect goods are directly sold to the consumers. After the screening period, the imperfect goods are transferred to the reworking center, where some imperfect goods are reworked at a price. The remaining defective products are sold as a single lot. A profit function is developed for this proposed production inventory model, which is highly nonlinear. The total profit is maximized using the graphical method to get the optimal production quantity and total business time. The profit function’s concavity is shown graphically by using the Mathematica software. To demonstrate the model’s feasibility, numerical examples are provided. Sensitivity analysis is carried out to highlight the findings of the suggested production inventory system and depict the managerial insights.

Recent trends of economic production quantity models (2000-2022) - a literature review

Recent trends of economic production quantity models (2000-2022) - a literature review

OPTIMAL POLICY OF THE INTERVAL EPQ MODEL USING C-L INTERVAL INEQUALITY

The objective of this work is to study the optimal policy of the classical economic production quantity (EPQ) model under interval uncertainty using interval inequality. To serve this purpose existing arithmetic mean-geometric mean (AM-GM) inequality is extended for interval numbers using c-L interval order relation. Then, using the said AM-GM interval inequality, the optimal policy of the classical EPQ model in the interval environment is developed. Thereafter, the optimality policy of the classical EPQ model in a crisp environment is obtained as a special case of that of the interval environment. Finally, all the optimality results are illustrated with the help of some numerical examples.

EPQ model with the effect of inflation and reliability for partial trade credit under fuzzy and cloudy fuzzy environment

The proposed study offers the first-of-its-kind economic production quantity model for deteriorating items having a demand rate to be price dependent under the effect of inflation and reliability with partial trade credit. The model is extended under an uncertain environment by assuming inventory parameters to be triangular fuzzy numbers and cloudy triangular fuzzy numbers. The objective of the study is to maximize the profit of the inventory system and to identify the most suitable environment for the proposed problem. Results are verified using the numerical study. Furthermore, the comparative study is presented to justify the nature of fuzzy and cloudy fuzzy environments. Sensitivity analysis under all environments is conducted to identify the most sensitive parameters of all.

Economic production quantity for a decaying item with stochastic demand and positive lead time

This paper considers a single-item, single-location production-inventory system subject to decay and random demand. Production occurs on a single machine at a constant and finite production rate. Shortages are allowed and partially backordered, while the other fraction of unmet demand is lost. A continuous review, lot size-reorder point policy is implemented to determine the size and the timing of production orders. The typical zero-lead time assumption made in existing economic production quantity models for a decaying inventory with random demand is relaxed here: when a production order is issued, a positive lead time is required before production starts. The long-run expected total cost per time unit is derived characterizing the stock dynamics as an Itō diffusion. Several properties concerning the inventory dynamics and the cost function are demonstrated, and an optimization procedure that finds the optimal solution for the developed cost function is presented. Numerical experiments are carried out with a twofold objective: (i) to validate the inventory model through simulation, and (ii) to evaluate the model sensitivity with respect to variations in parameter values.

Economic production quantity (EPQ) model in ‘pull’ managed single-machine multi-item production systems

Economic production quantity (EPQ) model in ‘pull’ managed single-machine multi-item production systems

A multi-objective economic production quantity model for deteriorating items with impact of the pandemic, social and environmental concerns

ABSTRACT The COVID-19 outbreak has posed significant challenges to the worldwide supply chain. As result, there is an urgent need to develop a model for the manufacturer that includes multi-phase manufacturing with fluctuating demand during various levels of pandemic and a supply system that takes into account the environmental benefits of the product and production. This study recommends inventory model to the company for estimating optimal production amount and replenishment cycle in order to reduce overall cost and maximize profit along with green product pricing and carbon tax. The current study considers models with and without shortages for instantaneously deteriorating commodities. Because of the social awareness concern, firms can avoid the suffering from labor shortage during the pandemic crisis. Numerical examples are given to demonstrate the model’s use. A sensitivity analysis of crucial factors was performed in order to uncover more sensitive parameters that offer a clear portrayal of current concerns.

Multi-item economic production quantity model under single valued bipolar neutrosophic environment based on possibilistic theory

It is challenging for a decision-maker to decide a proper decision in severe situations of multi-aspirated real-life problems.So there is always an ambiguity in the mind of decision maker. Keeping such vagueness in mind, this paper aims to incorporate some situation parameters imprecise in nature. The imprecise parameters are taken in single-valued bipolar neutrosophic environments. Different arithmetic operations on the single-valued bipolar neutrosophic number using the (α, β) cut method are proposed in this paper. Using this we have calculated the possibility mean of single valued bipolar neutrosophic numbers. A multi-item economic production quantity model with one time only discount is considered here with some parameters in single valued bipolar neutrosophic number as a case study of our proposed work. A possibilistic mean de-fuzzification technique is used here using possibility measures. Finally, numerical illustration and sensitivity analysis is done for different variables to emphasize the excellence of our proposed work.

Implementation of a circular supply chain model using reusable components in multiple product generations

The paper deals with a version of Economic Order Quantity (EOQ) and Economic Production Quantity (EPQ) models that considers the reusability of raw materials and components in multiple product generations. With the scarcity of available raw materials and disruptions in supply chains, production companies need to find novel solutions to meet demand. Additionally, waste management of used products is becoming an increasing problem for the environment. Our study presents available solutions for managing end-of-life products and aims to present a cost minimization EOQ/EPQ model. The model considers the use of components extracted from the previous product generation and new components during the production of the new product generation. The study aims to answer the following research questions (i) what is the optimal strategy for the company for the number of cycles of extracted and new components during the production? (ii) Which variables affects the optimal strategy of the company? The presented model allows companies to use the value created for a longer period, and reduces the amount of raw material extracted and waste generated.

The economic production quantity model with optimal single sampling inspection

Abstract This paper derives an inspection policy for an economic production quantity (EPQ) model under the assumption that a process may produce non-conforming (NC) items. In various stages of a production process, a department receiving an order uses a single sampling inspection policy to detect NC items. Under such a policy, a lot is accepted if the number of NC items in the inspected sample is equal to or less than the acceptance number. The proposed model considers both EPQ- and quality-related costs. Moreover, economic production order quantity, sample size and acceptance number are considered decision variables. A numerical example is presented, and a set of sensitivity analysis are provided to highlight the effectiveness of the proposed model. The results reveal that when the inspection cost is high, the classical EPQ model achieves a lower expected total cost for the production system compared with the EPQ model with the inspection. In contrast, when the NC cost is high, the EPQ model with the inspection policy outperforms the classical EPQ model, which can significantly decrease the expected total cost.