How Machine Vision Technology Increases Productivity for Film Lamination Applications

Machine vision investments are big decisions for companies, as the current business climate requires enterprises to make precise decisions on capital expenditures for future growth, which can include new equipment lines or even data management systems. Machine vision systems fit into this category, especially for companies tackling complex film lamination projects.

Machine vision technology has made advances in the manufacturing and packaging space in the last 30-plus years, and many come with data software systems for increased quality evaluation. The converting and flexible packaging industry has been using machine vision technology to inspect film substrates for dirt, voids, wrinkles, defects with extrusion applications and for basic registration.

Dr. Schenk Gmbh has been offering machine vision equipment worldwide to multiple industries, and it specializes in monitoring substrates in the flexible packaging space. The German-based company offers the EasyInspect and EasyMeasure branded solutions for converters, relying on the company’s Multiple Image Defect Analysis (MIDA) technology that consists of multiple optical channels in one camera line.

The MIDA technology produces real-time data that’s delivered to operators, and it uses one scan line, camera and multiple illumination sources (LED) to provide defect information. A defect will generate multiple images for analysis and will be categorized via the system’s classification rules tool. The system can create configurable reports to be shared with the continuous improvement or quality teams.

Real-time monitoring via the MIDA inspection technology is essential for DuPont Teijin Films with PET film production. “The inspection system finds film defects that would prevent our customers from using it, and we can also now draw conclusions about the status of our melt filters,” says Dr. Marianne Bausch-Koenig, quality and product development team leader at DuPont Teijin Films. “This machine vision technology gives us the ability to make a process change before the issue really gets serious.”

Moving to robust inspection systems can reduce the need for operators to continuously monitor flexible packaging film applications that demand high registration accuracy. Photo courtesy of ISRA VISION

Optimizing Data Management

Not only have camera technology and chip advances been a boon for industry leaders like Matrox and Teledyne DALSA, but large system solutions that integrate data management that feed into quality departments are also getting a lot of attention.

Recently, a U.S.-based flexible packaging company purchased ISRA VISION’s PrintSTAR inspection system to help improve productivity and managing defect data classification for its ongoing quality and continuous improvement efforts. The company, which produces packaging for the food and cosmetics industry, uses the inspection system for a specific cold-seal lamination application with an aqueous solution.

For this application, the inspection system monitors cold seal adhesive pattern levels — among other defects — while also overseeing print film registration. With the addition of the inspection system, the company was able to reduce operator involvement for print registration and remove print symbols for this operation, and reduce film material costs.

The inspection system automates the production process by using two, linear charge coupled device (LCCD) 4K technology cameras — a black and white (B&W) and a color — for the lamination application. The B&W camera follows the cold-seal adhesive that is applied to a metallized substrate on the reverse side of the printed film while the color camera inspects the already-printed side. Metallized substrates are challenging for inspection systems due to strong reflective properties, and print registration is difficult due to opaque properties.

The inline print inspection system can inspect both the front and back of a film substrate simultaneously, highlighting defects in both the print and the adhesive layer. Photo courtesy of ISRA VISION

These cameras are capable of finding defects as small as 270 microns at a web width of 42 in. and at a line speed of up to 1,000 feet per minute (fpm).

Defects for this cold-seal application include coating level irregularities, voids, streaks, scratches, skips, wrinkles, weaving or a hole in the substrate. The inspection software comes with ISRA classifications, but companies can add to the classifications during commissioning. The system allows for automatic defect detection on the line or a combination of operator involvement and system.

The technology behind this comprehensive inspection system includes cameras, an embedded sensor, field programmable gate array (FPGA)-supported image processing and embedded PCs. The image processing detects defects using image fusion and various filters, and then the data is examined by a PC module that provides inspection software and defect classifications.

For the lamination application at the mid-size packager, the inspection system sets acoustic alerts to warn operators if the cold-seal adhesive is misaligned to the print during production, allowing line managers to perform other production tasks.

Another critical element for defect detection is LED lighting. The company’s modular inspection systems when it comes to lighting include a basic profile for cooling, LED boards with adapted function, lighting with adapted optics and a controller box for lighting.

Whether deviations in the register or missing seals, the inspection system detects both individual and reoccurring cold-seal defects in real-time using high-resolution LCCD cameras with LED lighting. Photo courtesy of ISRA VISION

Two lighting approaches — reflective and transmission — meet requirements for clear web material and opaque, accordingly. For clear or translucent film material, the transmission approach produces light from the opposite side of the web while a reflective approach offers light reflecting directly onto the film material, such as the case with the print-side film in this lamination application.

As many plant floor operators understand, data management from web press lines is a challenge. With this lamination application, 1,000 fpm creates a large amount of data, and the inspection system can export information to custom or off-the-shelf enterprise resource planning (ERP) systems so quality or continuous improvement teams can examine production.

ISRA also offers an ERP software solution called ECOCKPITs that can gather data from multiple web lines and its inspection systems, and move this data into a Microsoft SQL server.

Going forward, flexible packaging companies, contract packagers and converters understand that new machine vision technology is a big decision that can add more complexity to the plant. However, as seen with this application, material savings and the ability to automate inspection offers increased utilization for a plant.

Data is growing, and converters and flexible packaging companies need solutions for increased demand — and automating inspection and the classification of this information is a good way to start.

Feature illustration by Valery Brozhinsky / iStock via Getty Images Plus