Analisis Lean Manufacturing untuk Mengurangi Pemborosan pada Produksi Pintu Aluminium dengan Metode Value Stream Mapping dan Just-In-Time

Abstract

Pemborosan waktu dan persediaan membatasi efisiensi operasi pada usaha mikro, kecil, dan menengah (UMKM) manufaktur yang berproduksi berdasarkan pesanan. Penelitian ini bertujuan mendiagnosis pemborosan pada aliran produksi pintu aluminium di Toko Sinar Bintang serta menyusun rancangan perbaikan berbasis Value Stream Mapping (VSM) dan prinsip Just-In-Time (JIT). Penelitian menggunakan studi kasus kuantitatif deskriptif-diagnostik terhadap sebelas aktivitas sejak penerimaan pesanan hingga instalasi. Data waktu proses dan waktu tunggu dipetakan ke dalam kategori value added (VA), necessary but non-value added (NNVA), dan non-value added (NVA), kemudian dievaluasi menggunakan total lead time, Process Cycle Efficiency (PCE), dan waste percentage. Hasil baseline menunjukkan VA 315 menit, NNVA 475 menit, NVA 675 menit, dan lead time 1.465 menit. PCE sebesar 21,50% dan waste percentage sebesar 46,08% menunjukkan bahwa waktu tunggu merupakan sumber pemborosan utama; tahap persiapan bahan baku menyumbang 240 menit atau 35,56% dari seluruh waktu tunggu. VSM berhasil memperlihatkan konsentrasi pemborosan pada pengadaan dan penyiapan material, antrean antarproses, pengiriman, serta instalasi. Berdasarkan diagnosis tersebut, penelitian mengusulkan material kitting berbasis pesanan, kartu kanban sederhana, batas persediaan minimum-maksimum, jadwal pemasok, standard work, dan penjadwalan pengiriman. Simulasi future state bersifat konseptual dan belum membuktikan dampak implementasi JIT. Kontribusi penelitian terletak pada diagnosis end-to-end untuk konteks UMKM make-to-order serta rancangan perbaikan yang dapat diuji melalui studi sebelum-sesudah.

Time and inventory waste constrain operational efficiency in make-to-order small and medium-sized manufacturing enterprises (SMEs). This study diagnoses waste in the aluminium-door production flow at Toko Sinar Bintang and develops an improvement design based on Value Stream Mapping (VSM) and Just-in-Time (JIT) principles. A quantitative descriptive-diagnostic case study was conducted across eleven activities, from order receipt to on-site installation. Processing and waiting times were classified as value added (VA), necessary but non-value added (NNVA), and non-value added (NVA), and then evaluated using total lead time, Process Cycle Efficiency (PCE), and waste percentage. The baseline results comprised 315 minutes of VA time, 475 minutes of NNVA time, 675 minutes of NVA time, and a total lead time of 1,465 minutes. The PCE of 21.50% and waste percentage of 46.08% indicate that waiting time is the dominant source of waste; material preparation alone accounts for 240 minutes, or 35.56% of total waiting time. VSM revealed concentrated waste in material procurement and preparation, inter-process queues, delivery, and installation. The proposed future state combines order-based material kitting, a simple kanban system, min-max inventory limits, supplier scheduling, standard work, and delivery appointments. The future-state figures are conceptual targets rather than evidence of implemented JIT effects. The study contributes an end-to-end diagnosis for a make-to-order SME and a testable improvement design for subsequent before-and-after evaluation.