Transportation

Transportation is the lean waste that hides in plain sight in almost every small shop, because the building was laid out before anyone knew what the current work mix would look like. A part travels three times farther than the operation requires because the saw is by the door, the mill is in the middle, the deburr bench is in the back, and nobody has moved any of it in a decade. The lean countermeasure is to look at the layout as something that can change.

"Every foot the part travels is paid for. By you, not the customer."

How transportation works as a waste

Transportation is unnecessary movement of material between operations, one of the eight wastes Taiichi Ohno catalogued inside Toyota. The waste shows up in several specific patterns:

• Inter-operation travel: parts traveling longer distances between steps than the layout requires.
• Out-and-back routes: material that crosses the same area twice, often because two operations are physically far apart.
• Multi-stage staging: parts that get loaded, unloaded, and reloaded several times before reaching the next operation.
• Inter-building moves: parts that have to leave the building for an outside vendor and return.
• Handling damage: damage that occurs during transportation, adding rework or scrap to the trip.

The standard diagnostic is a material flow diagram, sometimes called a spaghetti diagram for material. Draw the shop layout and overlay the path each part takes through the building. The diagram makes the cost of the current layout visible. In most small shops, a single part travels several hundred feet through the operation, often passing within ten feet of a related workstation that is sequenced 30 feet later in the route.

The countermeasures are about layout and sequencing:

• Cell layouts: grouping operations that share a part family into a tight footprint, so material travels feet instead of hundreds of feet.
• Point-of-use storage: positioning material at the workstation that consumes it.
• Pull signals: moving material only when downstream needs it, so partially complete parts do not accumulate in transit.
• Co-location: relocating two operations that exchange material so they sit next to each other.

The mistake is to optimize the forklift route or the tote-handling system instead of removing the trip. Faster transportation is still transportation. Removing the trip removes the waste.

Where transportation fits on the shop floor

In a 25-person stamping operation, transportation waste shows up like this. Raw coil arrives in the yard and travels 90 feet to the press. Stamped parts travel 60 feet to a deburr bench in the corner because that is where the bench was built. From deburr, parts travel 110 feet to the assembly cell, which is at the front of the shop near the shipping door. Completed assemblies travel 70 feet back to QC because the QC bench is near deburr. Total transportation per part: 330 feet, much of it backtracking.

A layout pass identifies that assembly and QC could swap, putting QC at the front near shipping and assembly closer to deburr. The change requires moving two benches, relocating one pallet rack, and rerunning power and air for the assembly cell, total cost about $4,000 and a Saturday's labor. Transportation per part drops from 330 feet to 120 feet, lead time on the stamping family drops by a day and a half, and a forklift driver previously dedicated to inter-bench moves is freed for receiving work.

Common mistakes with transportation

• Optimizing the route instead of removing it. Faster transportation is still transportation. Look first for what does not need to travel at all.
• Confusing transportation with motion. Transportation is material moving. Motion is people moving. Different fixes apply.
• Leaving layout unchallenged. The current layout is just the layout that exists. It is not a constraint. Most shops can move benches, racks, and even small machines.
• Solving transportation with bigger totes. Larger totes consolidate trips but increase queue time and damage. The fix is usually shorter routes, not bigger loads.
• Skipping the material flow map. Transportation is hard to see from inside the shop because everyone is used to the current paths. The map makes the cost visible.

Transportation and related Lean tools

Transportation is one of the canonical 8 wastes and is the close counterpart to motion, which covers movement of people rather than material. The standard diagnostic is a spaghetti diagram drawn for material rather than operators. The most effective long-term countermeasure is layout redesign, often built around point-of-use storage, which positions material at the workstation that consumes it.