Binroth, William (1992, ASQC) Siemens Automotive, Auburn Hills, Michigan
Eliminating product nonconformance results in quality production on an assembly line. Product nonconformance usually can be traced to the five "M's": Man; Method; Machine; Material; and Mother Nature. This paper describes fail-safe manufacturing techniques that can be employed to ensure the quality production of parts, particularly if product nonconformance is caused by human-related factors. These factors include communications issues (verbal, written), training issues (indoctrination, on-the-job-training), and human factors issues (substance abuse, attention span, physical and mental health). Actual behaviors associated with these issues include forgetfulness, lack of interest or motivation, carelessness, and deliberate errors by assembly-line operators. A literature search conducted by the author revealed that Shigeo Shingo invented fail-safe methods to eliminate the errors associated with these behaviors. Shingo refers to the techniques as "poka-yoke." For such problems as missing components, incorrect processing of defective parts, wrong components, and safety issues, Shingo proposed a combination of operator self-inspection, successive inspection by "downstream" operators with instantaneous feedback, and the use of fail safe devices, such as guide pins, error detection, and alarms, limit switches, counters, and checklists. An important benefit of fail-safe manufacturing is that it involves the knowledge, creativity, and experience of the floor operator. Fail-safe techniques, moreover, are inexpensive to install. The author's own experience at an automotive components supplier is reviewed to demonstrate the effectiveness of fail-safe manufacturing.
Assembly line methods,Poka yoke,Manufacturing,Nonconformities,Process improvement,Quality control (QC)