Dwell time at the buffer that never shows in WMS
The buffer looks full every afternoon. Inventory say the stock level is fine. Nobody can say whether cages sat for twenty minutes or three hours.
What WMS state misses about sitting still
A WMS or ERP bin tells you ownership and a named place group. It updates when someone posts a move. Between postings the cage can sit, shuffle two meters (about 7 ft), or wait behind a blocked aisle without a new booking. That quiet sit is dwell time. Lean teams already know dwell hides waiting waste. Without a location clock on the asset or the bay, the number stays folklore traded in the weekly meeting.
Logistics tracking measures dwell by combining place and time. When a tagged load or mover enters a defined buffer area and stays, the platform stores entry, exit, and duration. Medium-precision RTLS around 1–3 m (3–10 ft) is usually enough to know the cage is still in that buffer, not which millimeter of floor it owns. Coarse wing presence that covers half the building will call almost everything dwell and help nobody.
Why buffer dwell is a tracking job
Production blames logistics for late kits. Logistics blames production for early pulls. The buffer in between absorbs both stories until someone measures how long material actually waits. Plants that already run dense staging for WIP or supermarket lanes see this gap every day: inventory quantity looks healthy while flow is stuck. A full bay can mean healthy pull or a silent jam. Quantity alone cannot tell them apart.
twinzo stores those durations in the spatially oriented dataset under the live hall. Shift leads use live area views when a bay is overflowing now. Continuous improvement uses the same history for correlation and causality analytics when long dwell keeps preceding a starve two stations down. Live logistics, stored spatial history, and pattern work stay equal readers of that record. Replay after the shift is quiet is under when the event has already passed.
A typical afternoon the inventory screen cannot explain
At 15:05 the supermarket for line 2 looks packed. WMS shows target stock. Three cages at the back have not moved since before lunch. Drivers keep feeding the front face because that is what they see. The line starves on a sequenced part that is buried. Measured dwell on load tags would have flagged the long sits and pointed search at the back row. Mover-only tracking would have missed the sit once the last truck left. That object choice is under tagging the mover vs tagging the material.
Missing-cage search on the same stack is under searching the hall for a missing cage. Area geometry must match the real buffer paint, or dwell numbers lie. Map fidelity is under the map that logistics will trust.
What dwell is not
Dwell is not cycle time on the machine. It is not a yard detention clock for trailers at the gate. It is not a safety interlock. It is the measured sit of a tracked asset in a hall area you drew on purpose. If the area is drawn as the whole wing, dwell becomes too blunt to fund a layout change. If the area matches the real buffer, the number becomes a weekly review item logistics and continuous improvement can share.
How teams decide buffer dwell is worth measuring
1. Pick one supermarket or staging bay that always looks busy - Time how long people argue about it without numbers.
2. Draw the area to the real buffer, not the whole hall - Wrong geometry produces wrong dwell.
3. Prefer load tags when cages sit after the truck leaves - Mover-only tracking loses the sit once the forklift rolls away.
4. Review dwell beside starve timestamps for two weeks - If long sits never precede stops, you measured the wrong bay.
Buffer and area analytics sit under internal logistics optimization and production monitoring, with capability depth on the features overview. Rollout shape is under pricing.
Get in touch if you want to walk whether your buffers already measure sit time, or only inventory quantity.