Optimizing multi-item EPQ under defect and rework: A case in the plastic molding industry
Product availability is a key indicator of service performance and is closely linked to production planning. Inaccurate decisions in lot sizing may lead to either overstock or stockout, resulting in substantial financial losses. Classical Economic Production Quantity (EPQ) models generally assume pe...
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| Format: | Article |
| Language: | Indonesian |
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Universitas Pembangunan Nasional "Veteran" Yogyakarta
2025-06-01
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| Series: | OPSI |
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| Online Access: | https://jurnal.upnyk.ac.id/index.php/opsi/article/view/14740 |
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| author | Laila Nafisah Rika Apriyanti Magdalena Sinaga Apriani Soepardi Melati Salma Irianto Irianto |
| author_facet | Laila Nafisah Rika Apriyanti Magdalena Sinaga Apriani Soepardi Melati Salma Irianto Irianto |
| author_sort | Laila Nafisah |
| collection | DOAJ |
| description | Product availability is a key indicator of service performance and is closely linked to production planning. Inaccurate decisions in lot sizing may lead to either overstock or stockout, resulting in substantial financial losses. Classical Economic Production Quantity (EPQ) models generally assume perfect quality and ignore real-world factor such as defects, rework, and backorders. This study proposes an extended EPQ model for multi-item production systems that integrates random defect rates, rework, and backordering within a single framework. Unlike previous studies that focus on single-item scenarios or deterministic defect rates, this model reflects a more realistic setting faced by companies by accounting for stochastic defects, the cost of crushing and rework, and customer backorder fulfillment. The model aims to determine the optimal lot size and production cycle that minimize the total inventory-related costs. The proposed model is validated using real case data from a plastic molding company. Results show that the model yields cost savings of 0.19% compared to the current company policy. Although modest, these savings are significant when scaled across production periods. More importantly, the model demonstrates strong adaptability to operational constraints and provides a practical decision-support tool for industries managing multiple products, quality variation, and uncertain demand. |
| format | Article |
| id | doaj-art-8fc0abd54a734946a8a8fc18d7624608 |
| institution | Kabale University |
| issn | 1693-2102 2686-2352 |
| language | Indonesian |
| publishDate | 2025-06-01 |
| publisher | Universitas Pembangunan Nasional "Veteran" Yogyakarta |
| record_format | Article |
| series | OPSI |
| spelling | doaj-art-8fc0abd54a734946a8a8fc18d76246082025-08-20T04:01:02ZindUniversitas Pembangunan Nasional "Veteran" YogyakartaOPSI1693-21022686-23522025-06-0118120121210.31315/opsi.v18i1.1474011991Optimizing multi-item EPQ under defect and rework: A case in the plastic molding industryLaila Nafisah0Rika Apriyanti Magdalena Sinaga1Apriani Soepardi2Melati Salma3Irianto Irianto4Department of Industrial Engineering, Universitas Pembangunan Nasional Veteran Yogyakarta, Babarsari 2 Tambakbayan Yogyakarta, 55281, IndonesiaPT Indo Tambangraya Megah Tbk. Pondok Indah Office Tower III, Jl.Sultan Iskandar Muda Kav.V-TA, P.O. Box 178 Bontang, Kalimantan Timur 75311, IndonesiaDepartment of Industrial Engineering, Universitas Pembangunan Nasional Veteran Yogyakarta, Babarsari 2 Tambakbayan Yogyakarta, 55281, IndonesiaDepartment of Industrial and Process Engineering, Kalimantan Institute of Technology, Jl. Soekarno Hatta No.KM 15, Karang Joang, Balikpapan, Kalimantan Timur 76127, IndonesiaDepartment General Education, Faculty of Resilience, Rabdan Academy, Abu Dhabi, United Arab EmiratesProduct availability is a key indicator of service performance and is closely linked to production planning. Inaccurate decisions in lot sizing may lead to either overstock or stockout, resulting in substantial financial losses. Classical Economic Production Quantity (EPQ) models generally assume perfect quality and ignore real-world factor such as defects, rework, and backorders. This study proposes an extended EPQ model for multi-item production systems that integrates random defect rates, rework, and backordering within a single framework. Unlike previous studies that focus on single-item scenarios or deterministic defect rates, this model reflects a more realistic setting faced by companies by accounting for stochastic defects, the cost of crushing and rework, and customer backorder fulfillment. The model aims to determine the optimal lot size and production cycle that minimize the total inventory-related costs. The proposed model is validated using real case data from a plastic molding company. Results show that the model yields cost savings of 0.19% compared to the current company policy. Although modest, these savings are significant when scaled across production periods. More importantly, the model demonstrates strong adaptability to operational constraints and provides a practical decision-support tool for industries managing multiple products, quality variation, and uncertain demand.https://jurnal.upnyk.ac.id/index.php/opsi/article/view/14740epq modeldefective itemsmulti-item inventoryreworkbackorder |
| spellingShingle | Laila Nafisah Rika Apriyanti Magdalena Sinaga Apriani Soepardi Melati Salma Irianto Irianto Optimizing multi-item EPQ under defect and rework: A case in the plastic molding industry OPSI epq model defective items multi-item inventory rework backorder |
| title | Optimizing multi-item EPQ under defect and rework: A case in the plastic molding industry |
| title_full | Optimizing multi-item EPQ under defect and rework: A case in the plastic molding industry |
| title_fullStr | Optimizing multi-item EPQ under defect and rework: A case in the plastic molding industry |
| title_full_unstemmed | Optimizing multi-item EPQ under defect and rework: A case in the plastic molding industry |
| title_short | Optimizing multi-item EPQ under defect and rework: A case in the plastic molding industry |
| title_sort | optimizing multi item epq under defect and rework a case in the plastic molding industry |
| topic | epq model defective items multi-item inventory rework backorder |
| url | https://jurnal.upnyk.ac.id/index.php/opsi/article/view/14740 |
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