Inspection is now standard in the plastic industry!
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.
Lets look at the benefits
- Reduce customer claims and increased productivity on rework -Customer facing business benefits are probably the hardest to quantify and the most valuable. What price do you place on a lost contract? It can be part of any business strategy to include borderline product to fulfil a delivery. This is not a viable business strategy if the product quality has not been determined and stored. The cost of rework, if this product is returned, should be negated as the location of borderline issues will have been identified prior to shipping.
- Root cause analysis and process improvements- reduce inline waste and increase asset OEE. Vision networks integrated with sensor historians enable this.
- Smart converting- This is the use of data to optimize the follow on processes. An example of this is to rework a substrate roll prior to lamination. Why add the second layer to product that will be scrapped anyhow.
- Lower maintenance costs -can be expected through root cause analysis. Assets that are run at a steady output without constant stops due to quality issues will require less maintenance.
- Increased Output -Operators only deal with issues due to their process, there will be an increase in throughput.
What causes 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’s System enables the control of film quality during production. We analyze material defects and provide real time feedback for the operator. It documents the quality of the product and supports the operator with the optimization of the production process. It guarantees total quality control and monitors key metrics without contact. Easy to use operator interface with live feedback of all quality issues. It runs on a Windows platform with an easy to use touchscreen interface. Warning messages inform users immediately about defective production or when tolerance levels are exceeded.
OneBoxVision are experts at plastic film inspection and can offer advice on how to deploy your Capex to get the best value. Download our white paper to learn more and contact us to tell us about your issues.