cover
Contact Name
Desy Lusiyana
Contact Email
improsci@gmail.com
Phone
+6281324918200
Journal Mail Official
improsci@gmail.com
Editorial Address
Jl. Rajawali Gg.Elang 5 No.1 Drono, Sardonoharjo, Ngaglik, Sleman, DIY, Indonesia
Location
Kab. sleman,
Daerah istimewa yogyakarta
INDONESIA
Journal Of Engineering Sciences (Improsci)
Published by Ann Publisher
ISSN : 30323452     EISSN : 30317088     DOI : https://10.62885/improsci.v1i1
Core Subject : Engineering,
Journal Of Engineering Sciences (Improsci) merupakan peer-reviewed jurnal yang mempublikasikan artikel-artikel ilmiah dalam bidang industri. Artikel-artikel yang dipublikasikan di Jurnal Improsci meliputi hasil penelitian ilmiah asli (prioritas utama), artikel ulasan ilmiah yang bersifat baru (tidak prioritas), serta hasil kajian dalam bidang industri.
Articles 85 Documents
Production Scheduling Optimization Using The Campbell Dudek Smith (CDS) Method to Minimize Makespan in A Flow Shop Manufacturing System Venantius Almas Mario; Achmad Alfian; Heri Setiawan
Jurnal Improsci Vol 3 No 5 (2026): Vol 3 No 5 April 2026
Publisher : Ann Publisher

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.62885/improsci.v3i5.1130

Abstract

Background: Production scheduling plays a crucial role in improving manufacturing system efficiency, particularly in flow shop environments where jobs must follow the same processing sequence across multiple machines. At CV. Sinar Surya, the production scheduling for lathe machines is still conducted manually based on operator experience, resulting in high machine idle time, low machine utilization, and prolonged makespan. This condition causes inefficiencies in production processes and delays in order completion. Therefore, an effective scheduling method is required to optimize the production sequence and improve operational efficiency. Aim: This study aims to optimize production scheduling in a flow shop manufacturing system by applying the Campbell-Dudek-Smith (CDS) method to minimize makespan and reduce lathe machine idle time. Methods: The research was conducted at CV. Sinar Surya Palembang uses a quantitative approach. Data were collected through direct observation, interviews with production staff, and company documentation. The collected data include processing time for each job, production sequences, machine working hours, and existing production schedules. The CDS heuristic method was applied by transforming the multi-machine flow shop problem into several two-machine subproblems, which were then solved using Johnson’s rule to determine the optimal job sequence. Results: The existing production schedule yielded a makespan of 163 minutes and a total machine idle time of 140 minutes. After applying the CDS method, the optimal job sequence obtained was J4 - J5 - J3 - J1 - J2, which reduced the makespan to 147 minutes and decreased total idle time to 95 minutes. This represents a 16-minute reduction in makespan (approximately 9.8%), indicating improved production efficiency. Conclusion: The implementation of the CDS method improves production scheduling efficiency in a flow shop manufacturing system by generating a more optimal job sequence, reducing makespan, and machine idle time. Implication: The findings suggest that the CDS method can be an effective scheduling approach for manufacturing companies using flow shop systems, particularly for improving machine utilization, reducing production delays, and supporting better production planning and decision-making.
Designing a Cost-Efficient Inventory System Using The Economic Order Quantity Model for Construction Materials Distributors Indah Sry Devi Sipayung; Heri Setiawan
Jurnal Improsci Vol 3 No 5 (2026): Vol 3 No 5 April 2026
Publisher : Ann Publisher

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.62885/improsci.v3i5.1131

Abstract

Background: The construction materials distribution sector faces significant challenges in managing inventory due to fluctuating demand and the absence of systematic planning. Distributor Bintang Kerahiman, operating in Palembang and South Sumatra, currently relies on estimation-based inventory decisions, leading to frequent stockouts and overstocking. These inefficiencies lead to increased operational costs and lost sales opportunities, underscoring the need for a more structured, quantitative inventory control approach based on the Economic Order Quantity model. Aim: This study aims to design a cost-efficient inventory system by applying the Economic Order Quantity model and to compare its performance with the company's existing inventory method. Methods: A quantitative approach was employed using historical sales data from March to August 2025 across 30 selected products. Demand forecasting was conducted using the moving average method. Inventory parameters, including ordering cost, holding cost, safety stock, and reorder point (ROP), were calculated. The optimal order quantity was determined using the Economic Order Quantity formula, and total inventory costs were compared between the current method and the proposed model. Results: The implementation of the Economic Order Quantity model successfully reduces total inventory costs by optimizing order quantities and balancing ordering and holding costs. Across 30 products, the model demonstrated consistent cost savings and reduced inefficiencies. Additionally, profit improvements were observed due to decreased lost sales. For instance, profit for Afur BCP PVC Basket increased from IDR 990,000 to IDR 996,000, while Mold Cleaning Liquid increased from IDR 305,000 to IDR 330,000. Conclusions: The Economic Order Quantity model is more effective than the existing method in minimizing inventory costs, reducing stock imbalances, and improving service levels. The integration of safety stock and reorder point further enhances the system’s ability to handle demand variability. Implication. This study provides practical implications for construction material distributors by offering a data-driven inventory control framework. The findings support improved decision-making, cost efficiency, and customer satisfaction. Furthermore, the proposed system can be extended by integrating digital inventory applications and hybrid models for future research.
Comparing The Tear Resistance Of PVC Sheets With Dioctyl Phthalate (DOP) And Epoxydized Soybean Oil (ESBO) Plasticizers Prantasi Harmi Tjahjanti; Riki Nanda Setyo; Edi Widodo; Annisa Syakina
Jurnal Improsci Vol 3 No 5 (2026): Vol 3 No 5 April 2026
Publisher : Ann Publisher

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.62885/improsci.v3i5.1209

Abstract

Background. One of the PVC (Polyvinyl Chloride) products is a raincoat whose manufacture has been mixed with a DOP (Dioctyl Phthalate) plasticizer. The use of DOP in PVC since 1982 has been indicated as a chemical harmful to human health, especially causing gene mutations in the chromosomes of female eggs and infertility in men, as well as interfering with health. In addition, DOP is quite expensive. Aims. The purpose of the study is to replace DOP with the Epoxidized Soybean Oil (ESBO) plasticizer, which is non-carcinogenic, non-toxic, recyclable, and biodegradable. Methods. The PVC sheet products are tear-resistant and tested using the Elmendorf method. The mixing observed was analyzed using Fourier Transform Infrared (FTIR) spectroscopy. Result. The results using 100% ESBO meet the standard, even though the tear strength is still lower than with 100% DOP. Conclusion. FTIR analysis shows that a mixture of DOP and ESBO with a 50:50 ratio shows that other ingredients appear that do not interfere with the mixing process as a whole.
Analysis Of Occupational Safety Risks in IPAL Units Using the HIRARC Method Muhammad Iqbal Widagdo; Muhammad Nana Trisolvena
Jurnal Improsci Vol 3 No 6 (2026): Vol 3 No 6 June 2026
Publisher : Ann Publisher

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.62885/improsci.v3i6.1278

Abstract

Aims. This study analyzes occupational hazards and safety risks in the Wastewater Treatment Plant (WWTP) unit of a major food company in West Java (name and details anonymized for confidentiality). Methods. The Hazard Identification, Risk Assessment, and Risk Control (HIRARC) method and the fishbone diagram (Ishikawa) were applied. Result. The results indicate that activities in the WWTP unit present varying levels of risk, with dominant hazards including chemical exposure, slippery work environments, and poorly maintained machinery. The fishbone diagram reveals that workplace accidents are multifactorial, involving human, machine, method, and environmental aspects, while also highlighting the importance of chemical storage control, which, although less frequent, poses significant impacts on worker safety and operational continuity. Conclusion. These findings align with international standards such as ISO 45001:2018, the ILO Occupational Safety and Health Convention No. 155, and national regulations PP No. 50 of 2012 on Occupational Safety and Health Management Systems (SMK3), emphasizing that hazard identification, risk assessment, and continuous control must be implemented comprehensively to reduce workplace accidents and ensure industrial sustainability.
Analysis of Occupational Posture Risk and Physiological Load in Grinding and Moving HVAC Filter Products Using Rula-Reba, Heart Rate, and Borg RPE Iwan Aang Soenandi; Roy Theo Sabattian
Jurnal Improsci Vol 3 No 6 (2026): Vol 3 No 6 June 2026
Publisher : Ann Publisher

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.62885/improsci.v3i6.1284

Abstract

This study aims to study the risk of work posture, heart rate response, and operator workload perception in gluing, lifting, and laying HVAC filter products in the epoxy center area of PT XY. In this study, the Rapid Upper Limb Assessment (RULA), Rapid Entire Body Assessment (REBA), Heart Rate, and Borg Rating of Perceived Exertion (Borg RPE) methods were used. This study was conducted on six operators through field observation, photo/video documentation, Heart Rate measurement, Borg RPE assessment, manual handling recording, anthropometric measurements, and brief interviews. The results showed that, compared to gluing and lifting activities, laying activities had the most prominent ergonomic risk patterns. This is shown by relatively high RULA and REBA scores, the highest average heart rate, and the perception of workload which is generally in the weight category. In addition, gluing activities indicate postural risks, especially due to the posture of bending, reaching, and the use of nozzles and hoses during the work process. Because it involves moving products manually, lifting jobs have a relatively lower risk. However, this work still requires supervision. The mapping results show that improvement should be a top priority. Then followed by gluing and product lifting activities. Ergonomic improvements are aimed at adjusting the placement height of the pallet support facility, regulating the position of products, hoses, and nozzles during immersion, and reducing manual displacement distances when lifting. The results of the simulation of the reassessment of RULA and REBA based on the proposed posture showed the possibility of reducing the risk of working posture, especially in the excavation and laying work.