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OV-II Maintenance, Troubleshooting and Service Manual
INSPECTION/REJECTION PROBLEMS
Excessive False Rejects
2-8
The signal from the conveyor encoder is used to modulate the drive/brake
system and the Down Bottle/Jam functions.
The drive/sprocket assembly may be damaged by a loose production
chain or by pieces of metal, glass, or other foreign objects caught in the
production chain. Replace if damaged.
Also, check the encoder assembly for proper mounting. Replace if
damaged.
The following sections detail troubleshooting inspection and rejection
related problems including:
•
Excessive False Rejects
•
Rejecting Large Percentage of Bottles
•
Rejecting No Bottles
•
Rejected Bottles not Stable on the Takeaway Conveyor
•
Passing Faulty Bottles (Missed Rejects or False Accepts)
•
Faulty Bottles Detected But Not Rejected
•
Rejecting Incorrect Bottles
•
System Faults (Annunciator Lamp ON, No Message)
•
Complete System Failure
The false reject rate is a measure of detection reliability (repeatability) of
the Omnivision. The rate of acceptable false rejects varies depending
upon bottle type, glass characteristics, defect characteristics, production
speeds, and other factors.
Do not immediately assume that excessive false rejects are caused by the
inspection sensitivity being too high. Often it will be due to problems
with inspection components exposed to the production environment. For
example, false rejects caused by common items such as broken glass,
heavy soap, excess dirt, etc., are due to routine maintenance or
mechanical problems rather than the inspection problems.
To find the causes of excessive false rejects proceed as follows:
1. Check for and correct any mechanical/maintenance-related or bottle
handling problems as discussed earlier in this chapter.
2. Look at the bottles being rejected to see if there is an unusual bottle
characteristic which could be interpreted as a defect. Typical false
reject problems to look for include:
On the Base:
Industrial Dynamics Company, Ltd. © Form 42600 (10/03)
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