Pinhole inspection of plastic containers

100% inspection of soft containers, which is problematic with the differential pressure method



Plastic and resin container manufacturers


Thorough quality control is required at manufacturing sites due to the increase in awareness of reliability and safety in recent years.
Pinhole inspections of soft containers in particular is a challenge and manufacturers have been switching over from their current technique to a hydrogen gas detection method.

Application examples

Plastic and resin containers
[Image]  Plastic and resin containers

The challenge is deformation of containers caused by pressure

As containers that protect the freshness of food and cosmetics are required to be high quality, a one hundred percent inspection must be performed.
However, as soft containers are expanded in the differential pressure technique when pressure is applied, there is the danger that misdetections may occur.
This is because the differential pressure method detects defects by converting the changes in pressure inside the target workpiece to a leak rate.


With the current pinhole inspection that uses differential air pressure, misdetections are common and there is the danger of defective products being shipped as it stands now.


  • Deformation due to pressure change
  • Low detection sensitivity
  • Length cycle time

Conventional method

[Image]  Conventional method

Resolved with hydrogen gas detection method

A pinhole inspection can be performed with a high inspection sensitivity that is unique to gas inspection techniques, which was difficult with the air differential pressure method.
As the gas sensor directly detects gas that leaks from the pinhole, container deformation does not affect the results.
Inspection time can be reduced thanks to the immediate response of the hydrogen gas sensor, without having to wait for changes in pressure.


By employing a system that uses the hydrogen gas detection method, an accurate, 100% inspection rate is possible for even flexible resin containers.


  • Unaffected by container deformation
  • High sensitivity gas direct detection method
  • Immediate response supports mass production


[Image]  Solution