Design of pokayoke systems to increase the efficiency of function check oxygen sensor machine using programmable logic controller in manufacturing industry

This research was conducted at the industrial manufacturing company in the manufacture of automotive components. The company made cost savings by replacing preheating machine and characteristic check on line oxygen sensor machine. The machine that will be used to replace the preheating machine and check the characteristic is the function check machine. But the function check machine is not approved because the company cannot reach the determined target MOR (Machine Operation Ratio) at the time of trial, namely 90%. This is due to some problem in the machine. However, we focus on the problems with the highest frequency of down time misjudgement. The problems of down time misjudgement are caused from several factors, namely the human factor, the method factor, and machine factors. Problems stemming from human factors that determine the operator one part the result of checking, then the problem comes from the method that is the risk factor part OK (Good) and NG (Not Good) mixed, and the last issue of the factors that occur misjudgement machine when the checking part machine is OK. We design the pokayoke systems to increase the efficiency of function check oxygen sensor machine using Programmable Logic Controller (PLC). We use the pokayoke shutter systems and a photo electric sensor Omron E3T-ST12 as pokayoke sensors. We also add the text alarms on the HMI, so that the operator can easily determine the part is OK or NG. In addition, we also added spring in jig station checks each part so that the probe can touch the part, so there is no misjudgement. Finally, the misjudgement problem can be reduced to 0.14% and MOR on the machine can achieve the targets that have been set, i.e. 90%.