OneBoxVision Blog

The reasons to inspect plastic film using a camera system

Benefits of inspection on plastics

The modern extrusion and converting/laminating lines now use surface inspection systems as standard. Your customers demand 100% quality control.  All plastic film include some level of contaminates, arising from the production process or due to the nature of Polymers. Therefore gels are only a question of resolution. Extrusion and converting lines classify many defect types such as gels, black specs, fish eyes, holes, oil stains, insects, scratches, coating voids, air bubbles etc. These all originate from different issues but most all can have an impact on the further processing.

An extrusion line must control production using an advanced optical inspection system. These inspection systems locate all defects and identify the exact position, take a snapshot of the defect and alert the operator in real time. The end result is to avoid the production of waste. You can see benefits of deploying inspection in a number of areas including the film extrusion and converting process, the incoming raw material or at the final product especially during converting. By providing real time feedback on gel and black spec contamination, the machine downtime for die cleaning can be reduced and its capacity enhanced. In the extrusion and converting process a web inspection system can be used to monitor the raw material and allow you to choose the best raw material combination.

More about gels or fish eyes

Gels or Fish-eyes are small film defects are normally characterized by their area and protrusion above the film surface. A gel count is one of the standard film properties. Foreign polymeric materials that do not completely melt form gels. Contaminants such as dust from bulk containers, particles and foreign materials, e.g. from poorly cleaned silos, can also cause fish-eyes. During the transfer of PE pellets through pipes, some of the PE pellets melt and smear on the walls and form ribbon-like streamers (angle hair) that flake off into the pellet stream. While the streamers are still adhering to the walls, their large surface area comes into prolonged contact with atmospheric oxygen. This can form fish-eyes. Deposits on the inside wall of the extruder and prolonged thermal exposure during a stoppage can also lead to fish-eyes with brown spots.


Why film Inspection works?

The online measurement of film in a cast or blown processes provides real time data. Rinsing intervals can be optimized and the machine downtime reduced for die cleaning improving OEE. Other defects such as die/flow lines, oil stains, laminating defects, cracked coatings, air bubbles/inclusions, streaks, wrinkles, lack of adhesive or craters will also be detected. Classification of the defect is important, so that the operator can react. 


OneBoxVision is a specialist in building solutions for the plastics industry. Contact us and we can provide you with a free consultation or just go ahead and access our vision library to learn more. We provide solutions to industry leaders worldwide and can deliver an out of the box solution that will meet your requirements in weeks.

Access Vision Library ›Contact Us ›


Topics: Building and buying vision systems Plastic film inspection