Diagram Kendali S2 Menggunakan Repetitive Sampling Aslam

Evi Wulandari, Lisnur Wachidah

Abstract


Abstract. S2 control charts using Aslam's repetitive sampling are presented to monitor process variance by utilizing repetitive sampling schemes. This S2 control chart has a double control limit where the control limit has a coefficient determined by considering the Average Run Length (ARL) and the average samples number when the process is in control. This paper discusses S2 Shewhart control charts and S2 control charts using Aslam's repetitive sampling on the weight data of pulp packaging products SUN Pisang Ekonomis at PT. Indofood CBP Sukses Makmur, Tbk in October 2019. Then take samples every 15 minutes once every 25 subgroups/periods and 5 repetitions in each period. The result is the S2 control chart using Aslam's repetitive sampling is more sensitive than the Shewhart S2 control chart in detecting process shifts. This is evidenced in the Shewhart S2 control chart, all sample points are in control. Whereas the S2 control chart uses Aslam's repetitive sampling, there are several out of control sample points, namely at the 7th, 17th and 25th sample points.

Keywords: S2 control chart, Repetitive Sampling, Average Run Length (ARL), Process Shift.

Abstrak. Diagram kendali S2 menggunakan repetitive sampling Aslam disajikan untuk memantau varian proses dengan memanfaatkan skema pengambilan sampel berulang. Diagram kendali S2 ini memiliki batas kendali ganda dimana batas kendali tersebut memiliki koefisien yang ditentukan dengan mempertimbangkan Average Run Length (ARL) dan jumlah sampel rata-rata saat proses terkendali. Makalah ini membahas diagram kendali S2 Shewhart dan diagram kendali S2 menggunakan repetitive sampling Aslam pada data berat produk kemasan bubur Sun Pisang Ekonomis di PT.Indofood CBP Sukses Makmur, Tbk bulan Oktober 2019. Kemudian dilakukan pengambilan sampel setiap 15 menit sekali sebanyak 25 subgrup/periode dan 5 kali pengulangan pada masing-masing periode. Hasilnya diagram kendali S2 menggunakan repetitive sampling Aslam lebih sensitif daripada diagram kendali S2 Shewhart dalam mendeteksi pergeseran proses. Hal ini dibuktikan pada diagram kendali S2 Shewhart, semua titik sampel dalam keadaan terkendali. Sedangkan pada diagram kendali S2 menggunakan repetitive sampling Aslam, ada beberapa titik sampel yang tidak terkendali yaitu pada titik sampel ke-7, ke-17 dan ke-25.

Kata Kunci: Diagram kendali S2, Repetitive Sampling, Average Run Length (ARL), Pergeseran Proses


Keywords


S2 control chart, RepetitiDiagram kendali S2, Repetitive Sampling, Average Run Length (ARL), Pergeseran Prosesve Sampling, Average Run Length (ARL), Process Shift

References


Aslam, M., Nasrullah Khan dan Chi-Hyuk Jun. (2015). A New S2 Control Chart Using Repetitive Sampling. Journal of Applied Statistics. (Online). Vol 42, 2485-2496. (http://dx.doi.org/10.1080/02664763.2015.1043861/ diakses 20 April 2019).

Kuswendi, W. (2010). Bagan Kontrol Exponentially Weighted Moving Average Pada Proses Autoregresive Orde Satu. Skripsi Fakultas MIPA Universitas Islam Bandung.

M.B.C Khoo. (2004). S2 Control Chart Based on Double Sampling. International Journal of Pure and Applied Mathematics. (Online). Vol 13. 249-258. (http://ijpam.eu/contents/2004-13-2/11/11.pdf diakses 9 Oktober 2019).

Montgomery, D.C. (2005). Introduction to Statistical Quality Control, 5th Edition. New York : John Wiley and Sons, inc.




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