Pinhole is used in Pharmaceuticals packing machine to detect a hole in Lidding foil or Aluminium foil. So a pinhole detector is used to detection of holes. The Pinhole unit is placed in between forming station and the feeding channel.
The function of the Pinhole detector:
The primary function of the pinhole detector is to detect the presence of holes in aluminum foil.
Principle of Pin Hole Detector:
The pinhole detector is a multi-voltage device that detects pinholes, cracks, and damaged areas in non-conductive coatings on conductive substrates using the wet sponge principle. Any pinhole is penetrated by the wetting agents, which create a conductive path through the substrate.
A wet sponge test is a testing technique used to locate discontinuities in the coating film.
During the challenge test, the light source emitting light through-hole/damaged foil, and that light fell on the light detection device placed below the foil.
Perform the procedure as given in SOP to perform the challenge test. make a hole on foil with the help of the given needle and fix the reference standard of 25 microns (0.001 inches) over the hole. The hole should be seen through reference standards.
After affixing the reference standard to the foil, start the machine to pass the hole and start reference through the pinhole detector.
During this hole is sensed by the Detector, and at the same time, the red light of Detector will blink, and product feeding should be stopped, and the system should reject the same blister.
Perform the test at different positions on the foil, and the same shall be recorded in the Batch packing records.
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Frequency of challenge test:
Challenge test shall be performed at the start of batch or as given in the SOP.