People Proofing and Error Proofing
Manivannan lists four advantages of error-proofing; cost reduction, worker involvement in process improvement, defect reduction and variability reduction. But what if workers see error proofing as taking away all of their discretion and involvement, which in turn reduces their engagement elsewhere and leads to a downward spiral of automatic checking at every step and eventually automation and outsourcing? After all, a Gallup poll has indicated that only a quarter of American workers are actively engaged at work. Half are just putting in their time but not their energy or passion. The other quarter are actively disengaged from their job. That what if is addressed by Toyota through autonomation. Autonomation is sometimes called "stop-the-line" and means organizing work so that the slightest abnormality is detected immediately and the cause of the problem is remedied before more abnormalities can occur.
Taiichi Ohno, the father of the Toyota Production System, called autonomation "automation with a human touch." He drew an analogy between autonomation and our bodies' autonomic nervous system. That system governs reflexes such as breathing, heartbeat, and digestion. If we touch something hot, our autonomic nerves cause us to withdraw our hand without waiting for the brain to send a message. If a work abnormality occurs, the system should prevent further errors locally without recourse to central command. Of course if local is taken to mean at the tip of the tool, then autonomation can imply full automation and worker disengagement, but if local is taken to mean within the realm of control of the local operator, then it can mean the exact opposite.
So we should be diligent in applying mechanical Poka-Yoke devices. But also in encouraging production, support, clerical and managerial workers to self-inspect their own work and source-inspect the work produced immediately before their work steps. This means actively constructing, educating, measuring and rewarding value stream communication up the value stream of two types; clear, quantified customer needs and performance against needs and specifications. If we do this we can fully realize Ohno's and Toyoda's vision of Poka-Yoke & Jidoka (mistake-proofing and autonomation) as the pillars upon which Lean is built.
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