Penerapan Metode Forecasting dan Material Requirement Planning untuk Optimasi Perencanaan Produksi Pupuk Magnewish di PT Polowijo Gosari Group

Perencanaan produksi yang tidak didukung oleh peramalan permintaan dan perencanaan kebutuhan material yang tepat dapat menyebabkan ketidak seimbangan antara jumlah produksi dan kebutuhan pasar, sehingga berpotensi menimbulkan overstock maupun stockout bahan baku. PT Polowijo Gosari Group menghadapi permasalahan berupa fluktuasi permintaan Pupuk MagneWish serta terjadinya kelebihan persediaan pada salah satu bahan baku, sehingga diperlukan sistem perencanaan produksi yang lebih terstruktur. Penelitian ini bertujuan untuk menentukan metode peramalan yang paling sesuai, menyusun Material Requirement Planning (MRP) berdasarkan hasil peramalan, serta menganalisis penerapan forecasting dan MRP dalam mengoptimalkan perencanaan produksi Pupuk MagneWish di PT Polowijo Gosari Group. Metode peramalan yang digunakan meliputi Moving Average, Exponential Smoothing, dan Holt-Winters (Winter's Method), dengan pengujian akurasi menggunakan Mean Absolute Deviation (MAD), Mean Squared Deviation (MSD), dan Mean Absolute Percentage Error (MAPE). Hasil peramalan terbaik selanjutnya digunakan sebagai dasar penyusunan Master Production Schedule (MPS) dan Material Requirement Planning (MRP) dengan mempertimbangkan Bill of Materials (BOM), persediaan awal, lead time, safety stock, dan kebijakan lot sizing perusahaan. Hasil penelitian menunjukkan bahwa Winter's Additive Method dengan Seasonal Factor 12 merupakan metode peramalan yang paling sesuai karena menghasilkan nilai MAPE terkecil sebesar 292 dibandingkan metode lainnya. Hasil MRP menunjukkan bahwa perbedaan lead time dan ukuran pemesanan pada setiap bahan baku menghasilkan jadwal Planned Order Release dan Planned Order Receipt yang berbeda, sehingga kebutuhan material dapat direncanakan sesuai jadwal produksi. Penerapan forecasting dan MRP menghasilkan sistem perencanaan produksi yang lebih sistematis dalam menentukan jumlah produksi, kebutuhan bahan baku, dan waktu pemesanan material, sehingga dapat mendukung kelancaran proses produksi serta meminimalkan risiko kelebihan maupun kekurangan persediaan.

Kata kunci : Forecasting, Material Requirement Planning (MRP), Master Production Schedule (MPS), Holt-Winters, Perencanaan Produksi.

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Production planning that is not supported by accurate demand forecasting and material requirements planning can lead to an imbalance between production volume and market demand, potentially leading to overstocking and stockouts of raw materials. PT Polowijo Gosari Group faces problems such as fluctuating demand for MagneWish Fertilizer and excess inventory of one of its raw materials, necessitating a more structured production planning system. This study aims to determine the most appropriate forecasting method, develop a Material Requirement Planning (MRP) based on the forecasting results, and analyze the application of forecasting and MRP in optimizing MagneWish Fertilizer production planning at PT Polowijo Gosari Group. The forecasting methods used include Moving Average, Exponential Smoothing, and Holt-Winters (Winter's Method), with accuracy testing using Mean Absolute Deviation (MAD), Mean Squared Deviation (MSD), and Mean Absolute Percentage Error (MAPE). The best forecasting results are then used as the basis for preparing the Master Production Schedule (MPS) and Material Requirement Planning (MRP) by considering the Bill of Materials (BOM), initial inventory, lead time, safety stock, and the company's lot sizing policy. The results show that Winter's Additive Method with Seasonal Factor 12 is the most appropriate forecasting method because it produces the smallest MAPE value of 292 compared to other methods. The MRP results show that differences in lead time and order size for each raw material result in different Planned Order Release and Planned Order Receipt schedules, so that material requirements can be planned according to the production schedule. The application of forecasting and MRP results in a more systematic production planning system in determining production quantities, raw material requirements, and material ordering times, thereby supporting a smooth production process and minimizing the risk of excess or shortage inventory.
Keywords : Forecasting, Material Requirement Planning (MRP), Master Production Schedule (MPS), Holt-Winters, Production Planning.