Heat seal inspection of retort pouches

Enable 100% inspection after filling, which was difficult with visual and hand-push inspections



Food manufacturers


Thorough quality control is required at manufacturing sites of packaging containers due to the increase in awareness of reliability and safety in recent years.
Inspections of seal defects that occur in the process to fill retort pouches is particularly challenging, and manufacturers have improved these processes.

Application examples

Packaging containers such as aluminum pouches
[Image] Packaging containers such as aluminum pouches

The challenge is the large amount of missed defects

All products must be inspected in order to prevent claims due to defective food being shipped.
The current inspection involves workers visually inspecting the products, which means there is the possibility that defects will be missed due to pouch material, color, and/or shape.
Furthermore, the securing and high cost of workers is problematic due to the serious worker shortage.


With the current heat seal inspection that is performed visually by workers, defects are frequently missed and as things stand there is the danger of defective products being shipped as-is.


  • Detecting defects in non-transparent pouches is difficult
  • Inspection accuracy is reliant on workers
  • Insufficient number and high cost of workers

Conventional method

[Image] Conventional method

Resolved with compact ultrasonic sensor

The new method, with its impressive detection capability detects heat seal defects that are likely to overlooked in visual inspections.
As the ultrasonic sensor directly detects detachments of the seal that cannot be seen from the outside, human error does not occur.
A 100% inspection is possible just by installing the device on the existing equipment, and products can be delivered with peace of mind from the perspective of quality assurance.


Enables 100% inspection of pouches immediately after filling with high accuracy by installing ultrasonic sensors in each process.


  • Direct detection with ultrasonic transmission
  • Quality assurance through 100% inspection
  • Reduced risk of defective products being shipped


Ultrasonic beam focus technology at 1mm or less
[Image] Ultrasonic beam focus technology at 1mm or less

Example system

[Image] Inspection in the conveying process, Inspection in the filling process

Solution that resolved this challenge