Product tracking
Maintain the identity of the failed item between camera and reject despite normal line movement.
Track, remove and confirm failed products
Automatic reject systems for vision inspection
A correct camera decision only protects production when the intended failed product is removed or the line responds in a controlled, verifiable way.
Application-led design Proved against the real product, defect and production conditions.Direct answer
How does a vision inspection reject system work?
The inspection result is associated with a specific product, tracked to the reject point and used to actuate a suitable removal or diversion device. A robust design can monitor the reject mechanism, confirm the product entered the reject route and generate a controlled alarm or stop if rejection cannot be proven.
Typical project scope
What the system can cover
Each requirement is tested against representative products, normal variation, line speed and the agreed production response.
Reject method selection
Choose pusher, air blast, swing arm, drop flap, retracting belt, lane diversion or stop response around the product.
Reject confirmation
Use suitable sensing to confirm the expected product passed into the reject route rather than relying only on an output signal.
Bin and route monitoring
Monitor full-bin, bin-present, door or collection conditions where the application risk requires it.
Fault and bypass control
Define controlled behaviour for lost air, actuator fault, blocked product, disabled inspection or maintenance bypass.
Reject records
Log the inspection result, reject command and confirmation event where production evidence is part of the scope.
Engineering factors
What determines a dependable result?
Match the product
Weight, stability, fragility, speed, spacing and pack shape determine which reject mechanisms are practical.
Allow enough distance
The controls need a reliable tracking window between inspection and rejection, including acceleration, conveyor transfer and line-stop behaviour.
Define the failure state
The agreed risk determines whether loss of confirmation creates an alarm, stops the line, blocks release or requires operator intervention.
Production outcome
Turn the inspection into line control
The useful result is a repeatable decision that operators can understand and the production line can act on.
- Remove the intended failed product instead of only signalling a fault
- Detect loss of reject capability before unverified product continues
- Separate rejected product from normal production with controlled access
- Provide operators with clear alarms, recovery steps and reject evidence
Practical delivery
From requirement to accepted system
Characterise the product
Confirm speed, spacing, mass, stability, fragility and allowable handling.
Map the reject window
Measure the distance, tracking method, conveyor transfers and downstream risk.
Design monitoring
Agree actuator, air, bin, confirmation, bypass and fault-state signals.
Challenge every failure
Test good, failed, consecutive rejects, full bin, lost air, blocked route and line stops.
Decision guidance
Reject confirmation is a separate control from defect detection
A camera can correctly classify a product while the physical reject still fails because of poor spacing, a jam, lost air or a displaced bin. Treating detection, product tracking, reject actuation and confirmation as separate testable stages makes the complete system easier to prove.
- Define the maximum number of consecutive rejects the line must handle.
- Test product movement during starts, stops and speed changes.
- Agree who can use bypass and how bypass is indicated or recorded.
- Include reject-bin access and safe recovery in the operating design.
Related guidance
Continue planning your inspection
Questions, answered
Automatic reject systems for vision inspection FAQs
Which reject method is best for a vision system?
It depends on product weight, stability, fragility, line speed, spacing and available conveyor length. The mechanism should be selected from real product trials rather than by camera type.
What is reject confirmation?
Reject confirmation uses an independent signal or sensor to show that the intended failed product entered the reject route. It is different from confirming that the reject output was switched.
Can a reject system handle consecutive failures?
It can be designed to, but the maximum reject rate, actuator recovery time, product spacing and bin capacity must be included in the specification and acceptance test.
Can the system stop the line instead of rejecting?
Yes. A controlled stop, alarm, machine inhibit or diversion may be more appropriate where the product cannot be safely removed at speed.
Can rejection be added to an existing conveyor?
Often, subject to conveyor control, available length, guarding, product stability and a reliable tracking distance between inspection and reject. A survey confirms whether modifications are needed.