Motion

Motion is the lean waste that operators feel in their knees and shoulders, and the one shops most often try to solve by telling people to walk less. The lean view is the opposite. If the layout is forcing the walking, it is the layout that needs to change. Motion waste is a property of the workspace, not the worker, which is why the countermeasure is almost always to move the tools and materials, not to retrain the person.

"The operator is not slow. The bench is too far from the bin."

How motion works as a waste

Motion is unnecessary movement of people during work, and it is one of the eight wastes Taiichi Ohno catalogued inside Toyota. The category covers any operator movement that does not advance the product:

• Walking to a tool crib, a gauge station, or a stock rack the work could have been closer to.
• Reaching across a bench for an item that could have been positioned within arm's length.
• Bending and twisting to retrieve material from a non-ergonomic location.
• Searching for the right tool, fixture, or document that has no fixed home.
• Re-handling parts that should have been positioned once for the operation.

The standard diagnostic is the spaghetti diagram, an overhead sketch of an operator's path through a shift. The drawing reveals how much of the operator's movement is value-added (touching the part) versus motion waste (walking, reaching, searching). In most shops the first spaghetti diagram is a shock, because the operator's path is a tangle most of the day.

The countermeasures are layout fixes, not behavior changes:

• Point-of-use storage: tools and materials within arm's reach of the work.
• Shadow boards: outlined locations for every tool so missing tools are visible.
• Cell layouts: grouping operations that share material and skill into a U-shape, so the operator turns rather than walks.
• Ergonomic positioning: heights, angles, and reach distances designed for the work, not for the building.

Each fix is cheap individually. Together they usually cut operator walking distance by 30 to 50 percent in the first improvement pass, with no capital investment.

Where motion waste fits on the shop floor

In a 20-person fab shop running stamped components, motion waste shows up in a predictable pattern. The welding station has clamps in a drawer six feet from the work, so the operator turns away from the part every time a clamp is needed. The press operator walks to a shared gauge cart at the QC bench 35 feet away, three or four times per setup. The lead machinist runs the lathe, then walks to the central tool crib at the front of the shop for the next fixture, then walks back. Material totes sit on the floor, requiring the operator to bend for every load.

A spaghetti diagram of one operator's shift shows roughly 4,200 feet walked, of which the work would require about 1,400. Two hours of the shift is movement that produces nothing. The fix list: a clamp tree at the welding station, a dedicated gauge at the press, a tool cart positioned next to the lathe, and a parts stand at proper height. None of it costs more than a few hundred dollars. The reduction in motion is felt by the operators within the first shift after the changes.

Common mistakes with motion

• Treating motion as an operator problem. The operator is responding to the layout. The fix is layout, not pace.
• Confusing motion with transportation. Motion is the operator moving. Transportation is the material moving. Different categories, different countermeasures.
• Skipping the spaghetti diagram. Motion is invisible until somebody traces it. Without the diagram the fix list is guesswork.
• Solving motion with software. A digital work instruction does not bring the gauge closer to the bench. The fix is physical.
• Optimizing for cleanliness over reach. A pristine tool crib at the front of the shop is irrelevant if the operator works at the back. Position the tools where the work is.

Motion and related Lean tools

Motion is one of the canonical 8 wastes and is the close counterpart to transportation, which covers material movement rather than people movement. The standard diagnostic for motion is the spaghetti diagram, an overhead sketch of an operator's path. The most effective countermeasure is usually point-of-use storage, which brings tools and materials within arm's reach of the work.