The QC Quest

By Ellen Wuagneux, Associate Editor | February 10, 2006

quality control and inspection system suppliers keep striving for perfection as customers continue to demand it

Perfectionism has its advantages. At least that’s the case for equipment specialists on the quality control end of the nonwovens industry. These companies are offering increasingly sophisticated inspection systems designed to detect even the most subtle defects while keeping up with the need for ever-faster speeds, less waste and minimal downtime.

In the Wintress installation shown above, the cameras are in enclosures suspended above the web, which is back-lit using a red LED light line.
Topping the news in this segment recently is the formation of a new company, an event that is already changing the dynamics of a relatively small playing field. Just hitting the scene is 20-15 Vision Solutions, a new business concentrating on the high-end needs of nonwovens producers. Certainly not new to the industry themselves, Julie Zagozda and John Roberts, both formerly of inspection specialist AccuSentry, are heading up the new venture. The company offers web inspection systems for nonwovens and converted products such as wet wipes, as well as a complete line of inspection systems for absorbent disposable products including baby diapers, training pants, adult incontinence and feminine hygiene products.

“Our focus is to address the higher speed production needs and the detection of more subtle defects on today’s manufacturing lines,” explained Mr. Roberts, the company’s vice president. “Our systems are designed to allow the user easier access to the data, thus providing a more powerful production improvement tool. The availability of this data creates an environment where automated process changes can be implemented quickly and easily.”

The new company will join the ranks of several specialty suppliers who are working hard to meet heightened challenges in the nonwovens quality control field. One such company is San Diego, CA-based Wintriss Engineering Corporation, which has sold its Web Ranger inspection system to a variety of nonwoven material producers worldwide. Designed specifically for the inspection of web-produced materials, the Web Ranger system includes: the Opsis 7500ALS 7500 pixel smart line-scan camera, the web analyst quality control set-up program, the web inspector operator program and neural network-based advanced classification software.

All About Analysis

Formation analysis is a new functionality Wintriss has added to its nonwovens inspection systems. This feature provides real-time graphical density analysis of the nonwoven web while presenting a non-uniformity index showing how much variation there is in the material. This valuable tool is designed to meet the requirements of nonwovens producers to inspect for consistent product formation while simultaneously inspecting for discrete defects in their materials,” offered Vic Wintriss, president.

For its part, Allasso Industries, Inc., Raleigh, NC, offers a portfolio of laboratory and on-line analytical systems for quantitatively measuring fiber orientation, formalization and fiber uniformity, surface texture, pilling and moisture absorption. These machines were created to replace visual standards with simple techniques for measuring unbiased, reproducible characteristics of roll goods. “Over the past year, we have upgraded all of our software products, making them more user-friendly with more functionality,” stated Walter Chappas, Allasso’s president. “Most notable are the improved train functions on our surface texture analyzer and the new batch analysis options available on the uniformity analyzer.”

In addition to upgrades, Allasso has introduced an absorption analyzer that enables users to quickly and easily measure the rate and total uptake of liquids in a nonwoven. The analyzer comes with two testing adaptors that enable the measurement of both through-plane and radial absorption tests. “Unlike other absorption tests that use motor-driven and computer-controlled stages to maintain a constant pressure head, this analyzer uses an innovative reservoir system to maintain a static pressure at the sample without any moving parts. The resultant design is less expensive to build, more robust and produces more reliable results,” said Dr. Chappas.

From the perspective of Bunting Magnetics Company, manufacturing a product free from metal contaminants is more important today than ever—for safety, legal and cost reasons. While the company supplies and services electronic metal detectors and detector separators to a range of industries, its S series metal detectors was specifically designed to address the problem of nonmagnetic metal contaminants in textile applications. One model in this line, the Metron S, can be installed directly under conveyor belts and configured so that fabrics run in direct contact over the surface of the detector for maximum sensitivity. Its advanced, triple-coil technology ensures accuracy. Sensitivity is adjustable and a programmable product-effect compensation feature suppresses false signals caused by product or nonmetallic particles.

Additionally, one of Bunting’s newer products, the Metex Profi Line flat coil metal detector, can sense and signal the presence of even very small ferrous and nonferrous metallic contaminants in nonwoven and woven materials. Because of its compact design, the Metex Profi Line can be mounted almost anywhere, making it a convenient and versatile safeguard during the textile manufacturing process. Flat coil detectors are designed to ensure fabric safety and marketability.

The company’s Hump Magnets reliably remove ferrous fines and tramp iron from nonwoven textiles, including those that may be found during the production of diapers and personal hygiene products. Bunting also offers several magnetic metal separators that—when matched with electronic metal detectors in textile applications—provide more efficient and complete protection against metal contaminates. “Magnetic metal separators pull ferrous debris from the product stream, resulting in fewer reject events and reduced loss of good material,” explained Michael Wilks, the company’s director of marketing and sales. “Three examples include suspended plate magnets, cross-belt separators and magnetic separation pulleys,” he said.

Innovative Inspection Ideas

A specialist in the area of nonwovens inspection, Isra Surface Vision, Norcross, GA, has also rolled out several innovations. The company now offers the new Smash Advanced Inspection System designed for 100% on-line inspection of nonwovens such as spunbond, spunlace, carded, adhesive bonded, needlepunch, meltblown, wetlaid and airlaid. “The system scans the nonwoven material faster than competitive systems,” opined Brian Heil, Isra’s vice president, “resulting in better defect images with exact symmetry. Hundreds of features are extracted from each defect image for accurate automatic classification.”

Top to bottom: The Allasso absorption analyzer; a high speed inspection system from AccuSentry; and H. Hergeth’s Easyscan in action.

Featuring the Quickteach Classifier, the Smash system is able to precisely and quickly classify defects. Specific defect types can be mapped, trended, marked or alarmed. “Nonwovens producers do not want an inspection system that just detects more defects that create production bottlenecks,” said Mr. Heil. “Accurate classification enables intelligent marking of specific defect types and the ability to reliably determine the root cause of a defect to quickly eliminate the cause. Non-critical defects can be excluded in order to focus only on defects of interest.” He added that minor cross web deviations and fiber distribution differences can be trended and the process can be controlled within tighter limits, resulting in more consistent quality.

Another key player offering a full line of detection equipment is H. Hergeth GmbH. The German company offers two types of quality control systems: Cubiscan, which detects and eliminates foreign fibers before the web is produced at speeds up to 3000 kg/h, and Easyscan, which detects holes or defaults due to foreign fibers in the web. The Cubiscan is available in 800 mm, 1000 mm, 1200 mm, 1600 mm and 2000 mm working widths and covers the requirements of hygienic pad producers, nonwovens producers or fiber producers. The Easyscan system inspects nonwovens and a signal marks spots of difference in color or holes. “This system is very simple and attractively priced,” company president Hubert Hergeth commented. “For sophisticated inspection of roll goods, we cooperate with the company i2S for scanners and cameras,” he said. Mr. Hergeth added that due to the systems’ low cost, products that previously might not have justified on-line inspection are now being inspected.

AccuSentry, Inc., Marietta, GA, is also offering a newly expanded product line, which now includes image processing software and application-specific inspection systems for adult incontinence products, sanitary wipes,  pharmaceutical patches and feminine hygiene products. In addition to improvements to its core Sentry 9000 systems—which can now perform more than 2400 inspections per minutes—the company has introduced a registration system to accurately place components in high speed production lines as well as virtual camera capability, which allows multiple images of a product to be captured at different times to view different sections of the product. “This capability is useful in detecting large products such as adult incontinence items as well as for viewing products on very tightly spaced equipment with only a very small inspection window,” remarked Wei Siong Tan, AccuSentry’s president.

Daunting Demands

As market demands for higher quality and consistent materials increase, manufacturers are requiring higher levels of functionality for both QC and process control. End users are placing increasing demands on nonwovens producers for quality consistency and inspection system suppliers are banking on producers’ assumption that the way to economically achieve this consistency is through 100% optical inspection.

Meanwhile, most suppliers describe growth as slow but steady enough to boost R&D efforts to meet the needs of the changing marketplace. Many suppliers are expecting to see continued growth in web inspection through 2006, driven to some extent by the Chinese market, where quality has become a prominent concern.

Pictured above: A separation head pulley from Bunting Magnetics; Below:  ISRA Surface Vision’s Smash Advanced Inspection System.
Not only are customers demanding better quality and consistency, suppliers are also doing everything in their power to upgrade systems’ flexibility and versatility through a variety of measures. “The term ‘nonwovens’ covers a very broad range of products, and many manufacturers produce myriad product types within their organizations,” pointed out Mr. Wintriss of Wintriss Engineering. “An inspection system must be versatile enough to satisfy the inspection needs of all of the types of nonwovens that a particular manufacturer may produce.”

He went on to say that Wintriss is meeting this need through the architecture of its Web Ranger system, which can be used for any web inspection application. By establishing different “optical recipes” for different materials, the same system architecture is used throughout an organization. The flexibility of the system to utilize pre-stored recipes provides for quick change accommodations for some of the many new engineered materials.

Mr. Roberts of 20-15 Vision Solutions agreed that suppliers must think on their feet. “Our plan is to deliver innovative systems to meet our customers’ rapidly changing needs. Nonwovens markets and production capabilities are changing more quickly each year and our systems are designed to meet those changing needs easily and quickly,” he said.

According to Mr. Hergeth, flexibility is especially important for smaller producers who manufacture a range of different products on the same line. “Today, customers of smaller producers also require quality control, but since they cannot afford high cost and time investments, they need a simple, flexible and, of course, cost-effective solution,” he said. “A system for flexible production cannot reach 100%, but it can detect most of the common defects.”    

Beyond versatility and flexibility, speed remains a key goal. “As speed increases, so do the challenges to keep the line running,” offered AccuSentry’s Dr. Tan. The company is responding to this trend through products that offer comprehensive datagram, graph and charts to allow technicians to closely monitor the line.

“Smart utilization of instantaneous information is the key to keeping production lines running at top speed.” On a high speed production line, the ability to have instantaneous information is crucial to allow the technicians to make the necessary adjustments to keep the line running efficiently, he added.

Changing Challeges

As the industry moves forward, manufacturers face the ongoing challenge of keeping pace with demand, instituting new initiatives and staying ahead of competitors—challenges that are not isolated to the nonwovens industry.  An additional hurdle is the need for standardization in an increasingly global market, according to Dr. Chappas of Allasso. “Unfortunately, many manufacturers are resistant to the broad acceptance of technologies that might lead to new and increasingly difficult customer specifications. Many end users, on the other hand, don’t see QC as their problem and refuse to take an aggressive role in establishing quality standards. Both point to the absence of accepted standards as reasons for accepting new processes,” he said.

Although acceptance of these new systems is slow, Dr. Chappas continued, companies are realizing the value of quality products. “With this acceptance,” he predicted, “standards will be developed and what was once the exception will become required. Driven by a global operating space, manufacturers and end users are being driven away from the biased observation-based standards of the past to quantitative and analytical measurements,” he said. “As this equipment is accepted, it offers common standards for setting quality control worldwide without fear of the inherent bias of pictorial standards. As a result, these kinds of devices will quickly find their way into purchasing specification, especially where global purchasing and/or competitive bidding is required.” 

For 20-15 Vision Solutions’ Mr. Roberts, quantifying quality control is a tall order. “One of the biggest hurdles we face is to provide a system, complex in capability, to address the needs of the industry, yet simple and efficient for the operators to comfortably utilize. Quality control is still an item difficult to quantify and, therefore, it is sometimes difficult to justify the purchase of capital equipment.”

Are You A Visionary?

Despite substantial advances in quality control, suppliers admit there are still inspection needs that cannot be met with current technology in both the textile and nonwovens areas—structural analysis and cloudiness are two weak areas that come to mind.  Meanwhile, another important task continues to be justifying the cost of such systems with manufacturers. The basic knowledge of how inspection systems work and what can be achieved is still at a relatively low level among many potential users. Suppliers also report that many decisions are based on rumor rather than on applicable technical data.

“The use of imaging to evaluate nonwovens is still in its infancy,” commented Dr. Chappas of Allasso. “The first generation of on-line flaw identification systems using common algorithms and simple imaging hardware will be replaced with innovative software packages that integrate material science and the imaging systems with hereto unimaginable capabilities.” He added that much of this is already in development and will be available within the next few years.

The future also looks bright for Isra. “Simple, intelligent, self-learning systems that can be quickly implemented to optimize process variables to achieve consistent products will be introduced in the near future,” Mr. Heil predicted.   

“As advancements in computer hardware, software, optical sensors and other components progress, so do advancements in vision systems,” observed Mr. Wintriss. “Future systems will have increasingly automated functions, increased functionality and lower costs. Specialized lighting turns out to be very important in the detection of many subtle defects. Closed loop inspection systems will ultimately be available as vision system companies continually interface with production equipment manufacturers,” he concluded.

According to Bob Chiricosta of Natick, MA-based Cognex, the future holds a lot for web inspection users. “More user friendly information will be available in many different formats,” he predicted. “New information, such as accurate, meaningful, formation analysis, will give users data they can use to control their processes. And, the overall quality of materials will continue to improve for those manufactures who use automatic web inspection.”

Wrapping things up, AccuSentry’s Dr. Tan said that the technologies needed to address today’s production equipment include better camera light sensitivity, multiple-camera capabilities, virtual imaging, user-friendly graphing and reporting, close-loop control and interoperability. “The most significant hurdles to overcome in order to bring this technology forward is educating the plant managers and quality managers to incorporate these technologies into their production process. The acceptance of the benefits of these technologies in the rank and files of the production crews remains the greatest challenge,” he said. “The visionaries have already adopted the technologies.”