Defect Detection in Cigarette Manufacturing

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Cigarette making machinery - or its human operators – can be fickle. During any production run, a number of sticks will invariably sustain defects. But detection technology helps to identify and eject faulty product before it can reach the market.

By Thomas Schmid

Flagging, misalignment, wandering, double patching, v-cuts; a lot can go wrong with filter tips in the cigarette maker when the machine is badly serviced, wrongly calibrated or not properly monitored or operated. Issues with filling density, loose ends, leaking, torn, or ruptured paper tubes and a myriad of other mishaps also can be added to that already veritable catalogue. And the more sophisticated the cigarette stick (think slims, super-slims, and nanos) or its filter (multi-filters, anyone?) gets, the higher the tendency for potential defects. Multi-filter segments may be assembled in the wrong order or fixed skewed, affecting the filter’s proper functioning. Flavor capsules may occasionally be placed in the wrong position within the filter tip or filler, with negative effects on both taste and draw. And currently, quite trendy cigarette formats like super-slims and nanos may sometimes prove a little too delicate to withstand the crude mechanical stresses within the maker unblemished. Good to know, therefore, that there are plenty of suppliers of sophisticated gadgets around that help detect and eject faulty sticks before they can find their way into retail stores and possibly bring about repercussions for the brand image.

Moisttech Vision: Catching and Ejecting Defects On-Line

Australia-based company Moisttech Vision is well-known throughout the industry for its high-quality NIR moisture analyzers for tobacco during primary manufacture. But the company has also developed and recently launched a real-time inspection system, TP Vision, for detecting tipping zone defects during the secondary process. Installed directly on the cigarette maker, the system uses an ultra-high speed camera mounted above the inspection drum and scans every stick individually. The gained data is then analyzed by proprietary software for any tipping defects. Faulty cigarettes are electronically earmarked as “no good”, a process that can be followed visually by the operator on the system’s LED monitor. Using the maker’s integrated pneumatic rejecter, the faulty product is subsequently removed and discarded, effectively preventing it from reaching the packing stage.

Successful Test Runs Lead to Official Launch

Test runs in selected markets reportedly were so successful that the Australian company decided to fully launch the product globally in May 2017. ”The response from the industry has been amazing since then,” claims managing director Sean Herrington. “Over 60 systems have already been installed and even some of the largest players in the industry have embraced this new and exciting technology. That clearly proves that there was a real need for this type of system in the industry.” Traditional tipping defect systems, Herrington says, can only detect certain flaws. But the TP Vision approach will find practically all and any type of defect including double patching, wandering, misalignment, v-cuts, and flagging.

Easy Retrofitting on Older Makers Models

One distinct and important advantage of the TP Vision system is that it can be easily and quickly retrofitted to practically any type and model of existing maker, no matter how outdated or obsolete it may be. That is because it has been purposely designed as a stand-alone. It is not interfering with the maker’s controls. Instead, it simply sends a timing pulse in and sends a reject signal out. “We have fitted the system to pretty much every brand of maker imaginable and from what we have seen, it is accomplishing its job without fail and beautifully in every case,” asserts Herrington.

A Perfect Add-On to Expand Detection Range

But even newer cigarette maker models, which generally already come standard-fitted with a pressure testing system that automatically checks for leaking cigarettes, can benefit from the TP Vision installation. “The pressure testing system [in a modern maker] will only detect v-cuts and tears. But it doesn’t catch all these other types of defects that can occur, from misalignment and wandering to double patching, flagging, and more,” explains Herrington. TP Vision, he says, is thus an extremely useful add-on that ensures much more thorough inspection for all common defects. And it is lightning-fast, too: “Our system can inspect up to 12,000 cigarettes per minute. To put that into perspective, that is 200 sticks a second,” claims Herrington, adding that the references his company has accumulated from manufacturers of all sizes attest to TP Vision’s detection reliability and cost efficiency. “The system is self-teaching, designed to run 24/7 and requires neither calibration nor maintenance while working with 99.99% accuracy.”

TEWS ELEKTRONIK: The “Gold Standard” of Testing Equipment

Meanwhile, another global supplier of defect detection systems is German company TEWS Elektronik GmbH, headquartered in the northern city of Hamburg. Enjoying an excellent reputation within the tobacco industry for its broad range of both on-the-line and off-the-line instruments, most of the TEWS systems are considered “gold standard” equipment by many; a “must-have”, so to speak. “TEWS mainly concerns itself with on-line weight and quality control on the cigarette or filter maker, so we are very experienced when it comes to the majority of defect problems that can occur in cigarettes, primarily filling and profile faults and generally all issues related to capsule and multi-filters, such as missing, ruptured, falsely positioned or double capsules, the wrong assembly order of multi-filter components, problems with charcoal content, and so on,” elaborates the company’s executive manager, André Tews. “But apart from solutions for on-the-line application, we of course also have equipment available strictly for an offline lab setting or for deployment on the shooting lines,” he adds.

Defects Can Occur for Many Reasons

Defect issues, says Tews, can be down to various reasons, from mechanical stresses exerted on product within the maker to old, miscalibrated, or insufficiently maintained machines, among others. He also claims that slim cigarette formats are more prone to sustaining defects than regular-size sticks and that especially flavor capsules in slim or super-slim cigarettes can sometimes be particularly problematic to handle. But of course, issues also can occur across the board when sub-standard raw materials are used in the first place in order to save manufacturing cost. Tews also cautions that no (currently available) detection system can guarantee a 100% detection rate. “This is, at least for the time being, an unfulfillable dream or too expensive to implement,” he insists. “But given good training of the user and their thorough knowledge of how the deployed [detection] equipment works and reacts, we already can get pretty close to that dream rate.”

Two Machines, the Same Excellence

To reliably detect the aforementioned defects, Tews recommends his company’s range of moisture and density analyzing instruments that all deploy a unique microwave methodology. He particularly points out the TEWS MW 3012 machine, which is used on the production line for determining weight and moisture, as well as for inspecting filter plug properties. The system was originally introduced in 1998 and is today widespread in the industry. Meanwhile, the TEWS MW 4420 was developed strictly for offline use, but handles the same analyzing parameters as the MW 3012. “Both systems have undergone continuous further improvements over the last 20 years regarding their speed, measuring precision, detection rate, and overall user-friendliness,” says Tews. “You nowadays need big flexibility [in such equipment] because the design of cigarettes and filters is constantly changing and expanding. The good old standard kingsize cigarette and the simple acetate tow filter are today joined by a plethora of designs that are very different from one another and which often can be surprisingly complex.” Delving a little deeper into the subject, TEWS Elektronik’s global key account manager Jürgen Kröger explains that at the secondary processing stage the MW 3012 is capable of checking for a cigarettes’ accurate density profile, possible NTRPs stowed away in the filler, but also correct tobacco moisture. In the filter maker, the system recognizes wrongly positioned capsules in single and multi-filters as well as incorrect amounts (too much, too little) of charcoal, all of which are considered quality defects. Later on, during process control, the MW 4420 can then be deployed as an additional QC step to catch defects that might have slipped through earlier.

An Extensive, Multilingual Network

TEWS is of course not only selling its excellent instruments but also offers a comprehensive after-sales service package including operator training (either in-house or on-site), test runs and trials. “We maintain our own service points in Asia-Pacific, Europe, and the US as well as a network of partners in various countries. Our service teams can travel to wherever they’re needed and we can communicate in nearly ten different languages,” Tews says. But strong partnership cooperation between companies like his own on one side and machinery and cigarette manufactures on the other are imperative, too. “Only an open and cooperation-minded atmosphere such as this can lead to better results. In our company, we have even coined a word for that. We call it ‘co-improving’”.

With an extraordinarily broad choice of sophisticated defect detection systems at any manufacturer’s disposal (including from other leading manufacturers not mentioned in this article), there really shouldn’t be any substandard cigarettes finding their way into the marketplace. But even the best system cannot be absolutely perfect. “Cigarette packs containing defect sticks still do make it to the market and cause customer complaints,” says Moisttech’s Herrington, which could have a devastating effect on brand image if they’re slipping through too frequently. “It is very important,” Herrington concludes, “especially for the higher end brands.”