Heavy Part Presence Check at 12 s Without Stopping the Line
Moving heavy workpieces between operations has always been awkward in general and mechanical manufacturing. They are heavy, so manual lifting and turning risks impact damage to the part. The traditional answer is an operator's visual confirmation at the transfer node: so the line stops once and the part is handled once more. This project merged the two. The part passes with its carrier under a top-mounted vision head and presence is decided during transport, at about 12 seconds per part.
It cannot be touched and it cannot be stopped
It cannot be touched: contact risks impact damage, and the heavier it is the less anyone wants to try. And it cannot be stopped, because a stop-at-station check drags the transport cycle out. When both hold, a dedicated inspection station collapses as an idea: a station means extra loading and unloading, which multiplies the handling risk the check was meant to avoid. There is also an information gap. Whether a kit is complete at the transfer node decides whether the next operation can start, so the check must be early as well as reliable.
The carrier comes before the camera
Holding and imaging are in direct conflict: a solid plate supports a heavy part but blocks the camera's line of sight. The answer is an open frame, hollow above and below, with strength designed for the load and contact limited to the part's edges or part of its base. The upper opening gives the vision head a look-down window; the lower opening reduces frame weight and eases coupling to the conveyor table.
Most of the investment goes into carrier tooling and the conveyor interface; the vision side is one industrial camera and decision software. Retrofitting an existing line is the main use case: the carrier couples to the conveyor table and the head spans the line.
Presence only, and that is deliberate
The check is limited to presence, with no detail inspection. That looks like a compromise and is the highest-return decision in the project. A part present produces a contour in the imaging zone; an empty carrier shows open background. Occupancy alone separates the two, so the algorithm stays simple, thresholds loose and the result robust. Judging appearance or dimensions too would mean rebuilding the tooling for multi-angle imaging and stretching the cycle.
Photographed while moving: trigger and shutter
The part is in motion, so sharpness depends on when capture fires and how fast the shutter is. The vision head is interlocked with the conveyor table's positioning signal, so capture fires as the part enters the zone. Exposure sits far below the motion blur limit at that speed, which is enough for presence, and the verdict is output without waiting for the part to settle.
What happens after a missing part is found
The verdict is interlocked with conveyor control. An exception raises an alarm by rule, or marks the station result so scheduling decides between blocking and replenishing, without stopping the line. That step matters: if exception handling requires a stop, the cycle time saved upstream is handed straight back downstream.
Where this approach stops
The cycle is about 12 seconds per part, fully absorbed into transport with no extra waiting, subject to site acceptance results. It suits heavy parts with a stable seating surface that an open carrier can hold, where presence is the question: housings, bases, large castings or forgings. Where fine appearance or dimensional judgment is needed, a separate imaging scheme is required. Expecting this head to moonlight as an appearance inspector is how a station ends up doing neither job well.
Questions raised before retrofitting
Does an open frame weaken the carrier?
The frame is designed to the part weight and carries only edges or part of the base, with strength calculated for heavy-part conveying. The openings are imaging windows, not arbitrary material removal.
Is presence-only too simple to be worth it?
The question is only whether the part is there. Trading away extra classifications buys stability, low maintenance and cycle time.
Does the frame suit any heavy part?
Only parts with a stable seating surface the frame can hold at the edges or base. Anything else needs another carrier or method.