Quality Control of End Product in Paperboard with MEWMA and MEWMV Control Diagram Method (Case Study PT. Y Kediri Indonesia)
A Ihwah, Sucipto, B R Ekatama

Department Agroindustrial Technology, Faculty of Agricultural Technology, Universitas Brawijaya

Abstract

Cardboard is one type of paper that has a grammatic value above 200 g/m2. Cardboard making for fiber packaging and paperboard making process. Controlling the quality of competing products is important to improve product competitiveness. The purpose of this study was to approve paperboard and provide improvements at PT. Surya Pamenang Kediri East Java.
The research methods used are MEWMA (Multivariate Exponentially Weighted Moving Average) and MEWMV (Multivariate Exponentially Weighted Moving Variance). The data used are secondary data with a time span between 2016 and 2018. Observation values are taken from the average of each month in the last 3 years for the 9 variables measured. The nine variables are grammage, thickness, pull resistance, PS surface smoothness, BS surface smoothness, print surface smoothness, oil print, PS color, and BS color. Data were taken for ICB 230, ICB 210, WHI 230 and ICB 250 cardboard types are different. That is because every month the company does not always produce the four types. On the MEWMV control chart, the types of ICB 230, ICB 210, WHI 230, and ICB 250 successively have out-of-control points of 19, 10, 6, and 5, while in the MEWMA control, types of ICB 230, ICB 230, ICB 210, WHI 230, and ICB 250 respectively have out-of-control points of 13, 9, 9, and 6.
The main causes of product defects are repeated machine configurations and uneven spraying of pulp, and dew dripping over the production machine. In addition, other causes are adhesives and coating materials which are too thick/runny, and materials which are not suitable for production enter the process. Some suggestions for improvement that can be done are placing filters at the entrance of the coating material, and adjusting the temperature of the production machines environment.

Keywords: Cause-Effect diagrams, MEWMA, MEWMV, Statistical quality control

Topic: AGRICULTURAL ENGINEERING