Usulan perbaikan kualitas produk spun pile dengan Metode Six Sigma di PT. Adhi Persada Beton
P PT. Adhi Persada Beton merupakan anak perusahaan PT. Adhi Karya (Persero) Tbk yang memproduksi beton precast, salah satunya produk Spun Pile. Tujuan penelitian ini adalah untuk mengurangi jumlah produk cacat menggunakan metode Six Sigma. Metode ini memiliki 5 tahapan yaitu Define, Measure, Analyze, Improve, Control. Permasalahan yang terjadi yaitu rata-rata persentase cacat spun pile sebesar 0.71%, melebihi standar perusahaan yaitu 0.5%. Tahap define berfokus pada identifikasi masalah, tools yang digunakan yaitu diagram Supplier, Input, Process, Output, Customer dan penentuan Critical to Quality. Tahap measure bertujuan untuk mengevaluasi kondisi proses dengan peta kendali p berdasarkan proporsi jumlah produk cacat, perhitungan DPO, DPMO, dan sigma level. Nilai DPMO sebesar 617, dan tingkat sigma sebesar 4.73 sigma yang berarti setara dengan rata-rata industry USA, namun perusahaan ingin terus meningkatkan performanya dengan mengurangi produk cacat. Tahap analyze dilakukan identifikasi penyebab masalah menggunakan diagram Pareto untuk mengetahui frekuensi cacat dominan, algoritma Apriori, diagram Ishikawa mengetahui akar penyebab cacat, Failure Mode Effect Analysis untuk mengetahui mode kegagalan potensial dengan perhitungan nilai Risk Priority Number. Terdapat 5 cacat dominan yang terjadi yaitu sirip, lengket kulit, gompal, melengkung, dan jebol. Rule algoritma Apriori yang memiliki autran kuat adalah if terjadi cacat melengkung then terjadi cacat lengket kulit dengan nilai lift sebesar 1,6. Nilai RPN tertinggi sebesar 200 pada cacat lengket kulit, 150 pada cacat sirip, 140 pada cacat melengkung. Tahap improve mengusulkan perbaikan dengan 5W 1H. Usulan perbaikan cacat lengket kulit berupa form pembersihan cetakan, cacat sirip dengan membersihkan baut menggunakan rust remover, dan cacat melengkung dengan menggunakan produk thermocouple. Kesimpulan dari penelitian ini adalah memberikan usulan perbaikan pada produk Spun Pile namun belum bisa diterapkan karena situasi lockdown di pabrik.
P PT. Adhi Persada Beton is a subsidiary of PT. Adhi Karya (Persero) Tbk which produces construction materials including Spun Pile. The purpose of this research is to reduce the number of defective products using Six Sigma method. This method has 5 stages namely Define, Measure, Analyze, Improve, Control. The problem that occured was that the average percentage of Spun Pile defects was 0.71%, exceeding the company standard, which was 0.5%. Define stage focused on problem identification using SIPOC diagrams and CTQ determination. Measure stage aimed to evaluate the process condition with p-control chart based on the proportion of defective products, and calculation of DPO, DPMO, and sigma level. The DPMO value is 617 and the sigma level is 4.73 sigma, which was equivalent to the USA industry but the company still wanted to improve its performance by reduced defective products. The analyze stage carried out to identify the causes of problems using Pareto diagrams to determine the frequency of dominant defects, Apriori algorithm, Ishikawa diagrams to determine the root causes of the defects, Failure Effect Mode Effect Analysis to determine potential failure mode by calculating the Risk Priority Number value. Five dominant defects that occur were sirip, lengket kulit, gompal, melengkung, and jebol. Strongest rule that occurred in Apriori algorithm is if there is a melengkung defect then there will be a lengket kulit defect with a lift value of 1.6. The three highest RPN values were 200 for lengket kulit defects because the mould is not clean, 150 for sirip defects due to poor quality accessories, 140 for melengkung defects because the concrete is not harden yet. Improve stage proposes improvements with 5W and 1H. Proposed improvement for repairing lengket kulit is making a mould cleaning checklist form, sirip defects by cleaning bolts using rust remover, and melengkung defects using thermocouple. Control stage is to ensure the effect of the implemented suggestion on the process performance. The conclusion of this research is to propose improvements, but it cannot be implemented because of the lockdown situation at the factory.