Customer-specific products are a standard
NKL Contactlenzen is a subsidiary of Menicon, the Japan-based world-wide leader for lens materials, lens design and lens care solutions. At its production facilities in Emmen/Netherlands, NKL has installed a compact packaging machine with high quality and hygiene requirements in which customer-specific lenses are packaged efficiently and very carefully. The turnkey solution, which combines mechanical design with electrical automation, was developed and installed by Stevens Engineering. The vision and ID solutions employed in this tailor-made packaging machine were delivered by Cognex, the world’s leading supplier for machine vision systems.
Pack and go?
The job of the machine appears to be simple: After a final manual lens inspection, the operator places the lens in the lens holder and places this in the newly developed product carrier. The machine takes the product carrier with the lens holder and adds the special preservation liquid, seals it with aluminum foil and closes the lens holder’s cover – ready for shipping. Nevertheless, the whole process is outstanding. The machine has a remarkably small footprint and requires almost no manpower. The seal quality is extremely high. The fluid dosing is highly accurate. The cycle time is currently only 10 seconds. And each product and lens holder can be tracked at all times both during and after packaging thanks to Cognex ID technology and an SQL database.
Identification for accurate filling
The packaging machine is equipped with a rotary table with 10 positions for operating and controlling the lens, lens holder and the product carrier. One of the first jobs in the packaging machine involves being processed by the DataMan barcode reader from Cognex. The DataMan barcode reader is a small, fixed-mounted industrial high-performance barcode reader with a resolution of 752 x 480 pixels and a global shutter ideal for 1-D applications. Within NKL’s packaging machine, the reader scans the 1-D barcode label on the product carrier. Based on this identification, the lens holder is then accurately filled with one of two available liquids for preservation.
Filling checked by smart camera
An In-Sight vision system from Cognex now detects the lens. This is quite a challenge, since the lens is not only transparent, but also has different colours and is covered in liquid. However, the fully integrated In-Sight system is perfectly equipped for sophisticated applications like this thanks to its autofocus and fast image capture functions. The smart camera also checks if the lens is covered by enough fluid and whether there is any spoilage, e.g. drops outside the lens storage section. The camera system was configured with In-Sight’s standard software and inspection tools, so no additional scripting or manual configuration was required.
Verification at the end of the process
After that, the lens holder is sealed with aluminum foil and the plastic lid of the lens holder is closed. The lens holder lid is then printed with a UV ink 2-D matrix code to clearly identify the lens. The 1-D barcode on the product carrier and the 2-D matrix code on the lens cover outside are now read by another DataMan barcode reader. At this point, the reader’s integrated bright field is complemented by special UV lighting in order to detect the UV ink printed code. The product and packaging data acquired helps to verify the completion of the process in the SQL database and NKL’s management information system.
It took Stevens Engineering less than half a year to develop and install this customer-specific solution for NKL Contactlenzen. Following a further six months of usage within a “clean room” production environment, the customer is highly satisfied with the packaging solution which offers multiple functionalities on a very small footprint. The new machine is faster and requires less manpower, which leads to constantly high packaging quality. Compared to the previous solution, the quality checks and the packaging quality have been enhanced, fulfilling the high requirements for this delicate product. Currently, NKL and Stevens are already discussing further improvements for the next generation of this packaging machine. The optimum quality check and traceability will definitely be ensured by Cognex systems again.