Measurement of operator reliability level using the Human Error Assessment and Reduction Technique (HEART) method

Workers can cause harm to the company caused by human error. Human error has a close relationship with the level of reliability of a worker. One result of the low level of reliability of workers is product defects. PT. X is a company that manufactures engine and molding spare parts and dies, using automatic machinery. There are defective products on production, with an average number of defects of 1.2% per month above the disability tolerance set by the company of 0.2%. The types of defects in the product are corrugated surfaces, rough surfaces, mismatched pieces, inaccurate sizes, and the presence of foreign matter attached to the product. This product defect occurs in the milling machine. This study aims to determine the level of operator reliability at the milling work station that affects production results. This research is a descriptive qualitative research using the Human Error Assessment and Reduction Technique (HEART) method to determine the level of operator reliability. The biggest HEP measurement results experienced by each operator is when the activity is set up and operating the machine by the program, which ranges from 0.7936 to 0.9104. The level of reliability (Rm) for operators 1, 2, 3 has a value of Rm in succession of 0.4350; 0.3627;.2005. Rm value <0.5 indicates the level of reliability which is categorized as low. This low level of reliability is caused by the absence of work procedure standards, lack of supervision of operator performance, low work morale, lack of operator experience, and no effective communication between the operator and programmer when inputting coding on the machine.