Production Improvement of Tuna Chunks in Glass Jar

Abstract

In manufacturing process of tuna with vegetable oil in glass jar product, loosened jar cap is a major cause of the product defect and this will waste resources including time, labor, and raw material in the manufacturing line. According to investigation of 180-gram packing weight, it was found that the percentage of the loosened jar cap is 0.20% of the output per day. This research was started from collecting concerned data in the production line, then analyzed the data by Why-Why analysis so as to find the root cause of the problem. After that the One-Sample t-Test and One-Sample Kolmogorov-Smirnov Test were used to analyze data. The investigation confirmed that semi-automatic oil-filling machine is the root cause of the problem. Furthermore, weight of tuna before bottling is lower than the regulated value. The factory had improved the process by 1) controlling the process of weighing tuna to maintain the regulated weight at 120±3 grams, 2) improving the oil-filling system in order to control the amount of oil to be 60±2 grams per jar, and 3) improving jar feeding conveyer. After improvement, both the weight of tuna and the oil were in settled values. The improved conveyer can fasten jar tightly. These will lead to total weight of each jar being within the settled value. As a result of the project, there was a decrease in the percentage of the product defect at 0.09%. Therefore, the factory can reduce the cost of jar cap by 889 baht per month and the rework cost by 4,789 baht per month.