OneBoxVision are experts in plastic film inspection and have identified some of the key benefits gained from the installation of a 100% inspection system on plastic film extruders.
The modern extrusion and converting/laminating lines now use surface inspection systems as standard. Your customers demand 100% quality control.
Benefits of inspection on plastics
All plastic film include some level of contaminates, these contaminates arise 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;
- Black specs.
- Fish eyes.
- Oil stains.
- 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.
Gels or fish eyes
Gels or fish-eyes are small film defects normally characterised 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.
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 will also be detected, such as;
- Die/flow lines.
- Oil stains.
- Laminating defects.
- Cracked coatings.
- Air bubbles/inclusions.
- Lack of adhesive.
Classification of the defect is important, so that the operator can react.
The inline measurement of pellets provide LAB color values, the yellowness Index, detect dust and impurities and can measure the form and roundness.
It's clear that a web inspection system is a must to control quality. What is also clear is that it can also be used to minimize line downtime, optimize cleaning processes, identify the best raw material and improve the OEE of existing lines. OneBoxVision are experts at plastic film inspection and can offer advice on how to deploy your CapEx budget to get the best return.
Download our latest whitepaper below on plastic film inspection to learn the key areas involved. If you have any questions or would like more information do not hesitate to contact us.