Auditing the 8 Manufacturing Wastes (TIMWOODS) at the Gemba
A practical, floor-level walk sheet to identify hidden inventory queues, non-value-added operator motions, and process bottlenecks.
1. Why Lean Audits Fail from Conference Rooms
You cannot spot waste on a PowerPoint slide in an air-conditioned office. Taiichi Ohno, the father of the Toyota Production System, famously drew a chalk circle on the shopfloor and forced supervisors to stand inside it for hours until they learned to "see".
Waste in manufacturing takes eight distinct forms, remembered by the acronym TIMWOODS: Transportation, Inventory, Motion, Waiting, Overproduction, Overprocessing, Defects, and Skills Underutilization.
Among these eight, Overproduction is the deadliest sin. It hides all other problems under mountains of work-in-progress (WIP) buffers, creating the illusion of safety while silently bleeding cash.
Overproduction is the fundamental waste. When you produce parts faster than customer Takt time, you conceal machine breakdowns, quality defects, and long changeovers behind inventory cushions.
2. Motion vs. Transportation: The Spaghetti Diagram Audit
Many plants confuse Motion (waste generated by the operator) with Transportation (waste generated by moving materials). Both create zero value for the end customer.
When we audited our automotive stamping line, we tracked Operator B’s footsteps with a pedometer. Over an 8-hour shift, he walked 8.4 kilometers simply fetching dies, retrieving fasteners, and hunting for torque wrenches that had no designated homes.
By applying strict 5S visual toolboards and bringing fastener totes within the 45-degree ergonomic golden zone, we eliminated 6.1 km of daily walking per operator, instantly reclaiming 48 minutes of productive assembly time.
3. Eliminating Inventory & Waiting with Takt Time Pacing
The antidote to inventory accumulation is pacing production strictly to customer consumption rhythm (Takt Time). If daily demand is 960 parts and your net operating time is 28,800 seconds (8 hours minus breaks), your Takt Time is exactly 30.0 seconds per part.
Running a press at 18.0 seconds per part when downstream packaging can only handle 30.0 seconds does not make the plant efficient; it creates a dangerous mountain of WIP inventory that requires extra forklifts and floor space.
Weekly 8-Waste Gemba Walk Audit Protocol
Stand at the bottleneck workstation for 30 consecutive minutes without speaking or interrupting operators. Record every micro-pause.
Count the physical units sitting between operations. Any buffer exceeding 15 minutes of Takt time is flagged as red-tag excess inventory.
Draw physical walking paths on a printed floor plan. Highlight any path exceeding 3 meters to retrieve tools or raw materials.
Time 10 consecutive finished units with a stopwatch. Verify variance from customer Takt time does not exceed ±5%.