Vision system success
Image capture technology helps Johnson & Johnson reduce waste, improve efficiency
By John Lewis
In Thailand, the consumer products market remains solid due primarily to a high level of government support and strong exports. In order to leverage this market most effectively, global manufacturing companies need to find new ways to increase productivity and lower production costs while still delivering the highest quality consumer goods.
U.S.-based Johnson & Johnson is one of the world’s largest producers of Fast Moving Consumer Goods (FMCG) such as baby care products, consumer health care products (Modess and Carefree), beauty care products (Clean & Clear and Neutrogena), and many others. In addition to China and India, Johnson & Johnson chose Thailand to be a regional manufacturing hub. The company’s factory is located in the Lad Krabang Industrial Estate Zone and employs more than 500 people.
Johnson & Johnson has an impeccable reputation for quality assurance (QA) because it has put the strictest standard of quality control in at every stage of the production process. The company has made significant investments in technology and factory management systems, production process management, work safety and health standards, environmental impact analysis, and socially responsible activities.
Migration to vision sensor systems
Prior to adopting a vision system in the production line, the company used an existing sensor system to check the completeness of material layers and other components of sanitary napkin products. However, when additional product features were incorporated into new product designs, the existing sensor system could not read the new release paper pattern and color properly. The existing sensor system triggered the shutdown signal, which caused the machine to stop. Every time the operation staff needed to adjust the sensor position, it resulted in significant production downtime and unnecessary waste.
In order to overcome this problem, Johnson & Johnson decided to upgrade their existing sensor system to a vision system that uses image capture technology. The goal with changing technologies was to reduce expenses associated with an incomplete production process and increase the production efficiency and effectiveness of the factory. More importantly, Johnson & Johnson deployed a vision system to maintain the standards of every product the company makes. According to the company’s slogan, “We never pass defects to customers.”
Johnson & Johnson engaged an engineering firm located in Thailand, Servo Dynamics Company Limited, to advise them on using a vision system to solve these quality problems. Based on the engineering and feasibility analysis that evaluated the application and vision systems to meet the requirements, Servo Dynamics recommended Johnson & Johnson conduct a feasibility study and evaluate several vision systems products.
Servo Dynamics developed an engineering and feasibility analysis including detailed attributes required by a vision system for the application including efficiency, functions, valuation speed, reading rate speed, set labor, software configuration, factory network communication options, business enterprise communications with back-end systems, and investment criteria. Based on analysis and testing, the team selected Cognex vision system components to satisfy Johnson & Johnson’s application requirements.
Compact vision cameras
Compact vision cameras are used to ensure every piece of product meets Johnson & Johnson high quality standards by performing 100% final inspection checks prior to the product being packaged for shipping. The machine vision system performs various types of inspections, verifies quality and assembly to determine whether items meet requirements, and rejects those that don’t. Quality checks include detecting defects, functional flaws (example: such missing components or irregularities), and surface inspection for cosmetic flaws. The cameras applied to meet application requirements are compact (30mm x 30mm x 60mm) with 640 x 480 resolution and a 60 frames per second (fps) acquisition rate based on minimum exposure and a full image frame capture. The camera can be mounted at angles of up to 45-degrees to allow mounting in tight spaces on robots and hard-to-reach machinery anywhere on the production line.
High resolution camera
A more powerful camera was used to capture images of the inner and outer rim of sanitary napkins to check if the materials in each layer are complete and there are not any missing layers and to determine if the materials are properly aligned. In a typical gauging application, a camera mounted above or to the side of a part captures an image of the part to be measured as it enters the field of view. The image is then analyzed using gauging software tools, which calculate distances between various points in the image. Based on these calculations, the vision system determines if the part dimensions are within tolerance. If dimensions fall outside of tolerance, the vision system sends a fail signal to a controller (the PLC, for example), which in turn triggers an alignment correction and reject mechanism to eject the flawed product from the line. This application required a vision system with high performance of 10–20 times the final inspection system.
An all-in-one industrial sensor system with built in camera, processor, lighting, optics, and I/O in an IP67 enclosure capable of detecting and inspecting up to 6,000 parts per minute is used for vision capture of the glue strip on the sanitary napkin products to replace the original sensor system. The system verifies the presence or absence of parts or features on products, or to check for the correctness of their shapes. By replacing the traditional sensor system, Johnson & Johnson was able to eliminate costly fixtures and eliminate the downtime associated with making mechanical adjustment for different products. This approach offers improved productivity and manufacturing flexibility for mixed-model processing and allows production of multiple products on the same production line to help achieve just-in-time delivery. Using machine vision eliminates the need to physically handle the products, lowering the risk of contamination due to human contact.
Vision reads barcodes, labels
A vision system that can read barcodes, characters printed on labels, Data Matrix codes, or alphanumeric characters marked directly on the products or package is used on the Talcum production line. In addition to recognizing and verifying characters and reading barcodes for identification, the machine vision systems can also examine patterns to identify items based on color, shape, size, or assembly. Identification helps the company with better management of inventory for work-in-process and finished goods, as well as improved asset tracking. This also helps to enable more efficient containment strategies while providing production data for process monitoring and quality control metrics to help quantify problematic areas in a plant, such as bottlenecks. Finding a standard vision system that accommodated all requirements avoided the need for a custom system.
Systems integration teamwork
The engineering team of Johnson & Johnson worked in conjunction with the experts from Servo Dynamics to study and plan the implementation and integration of the vision system into the factory system. At the beginning, addressing the inconsistent readings caused by light from the LED screen in various positions was a significant barrier to successful installation. The Servo Dynamics team solved this problem by programming the software to put an adjustment on the installation position and the alignment of light and color value through the control body of the programmable logic controller (PLC) and ensuring this functionality can be easily applied and conveniently configured. The installation of the vision systems took only two months to complete. To date, Cognex vision systems are installed in eight Modess sanitary napkin production lines and one production line of Care Free sanitary napkins. Vision systems are also being installed in all four production lines of baby talcum powder.
Johnson & Johnson has been successful in solving the problem of sensor error, reducing the production downtime rate to 0%, and reducing waste from machine ramp up. In the first year alone, the cost savings from preventing machine shutdown and reducing waste was valued at almost $28,000.
“In the past, we had to use many Quality Assurance officers in random inspections of products at 15 minute intervals, including the operation officers who had to align the sensor system or electrical system manually. With the vision systems in place, these jobs are easy and convenient, as they only need to control the value alignment and make any adjustment right from the monitor screen,” said Jenwich Mitravijarn, engineer leader at Johnson & Johnson.
The vision systems are easy to set up and configure even for a first time user. “Another significant factor is Cognex’s before and after sale service. Cognex provides prompt support and expertise. … This really gives us more confidence to invest in the future,” he said.
Looking ahead, Johnson & Johnson is considering extending the installation of vision systems in the production lines of other products to cope with the higher market demand. Maintaining high-quality products has been, and continues to be, Johnson & Johnson’s first priority.
ABOUT THE AUTHOR
John Lewis is market development manager at Cognex. Formerly a technical editor for an engineering magazine, he has been writing about packaging technology, machine vision, factory automation, and other technology topics since 1996. He has published hundreds of articles in dozens of trade journals and holds a B.S. degree in chemical engineering from the University of Massachusetts, Lowell. E-mail him at firstname.lastname@example.org.