Weighing it up

NGF finds out how checkweighers can help to improve efficiency, cut costs and provide increased safety and quality. With OCS Checkweighers, Mettler Toledo, Bizerba and Ishida Europe

“In reality, the majority of checkweighers available on the market are made to a single specification and do not provide the option to amend conveyors and other components”
-Ingolf Latz, OCS Checkweighers

What key features should a checkweighing solution possess if it is to provide maximum value to a food producer?
Ingolf Latz. Every application is orientated by product handling and accuracy, as these two factors will play the biggest part in results generated. This sounds logical but in reality, the majority of checkweighers available on the market are made to a single specification and do not provide the option to amend conveyors and other components, in reference to requested terms of working and the given working environment.

For a checkweigher manufacturer to have its own in-house design team, is therefore most beneficial to the end user. Using the right weight measuring technology guarantees a fast Return on Investment (ROI). OCS only uses the principal of Electromagnetic Force Restoration (EMFR). Giving two major advantages: no material fatigue, which you would normally find with strain gage based checkweighers, and the reproducibility is significantly better with the weighing of each product becoming much faster. A dedicated software will provide the tools to maximise this benefit.

Gunter Schilpp. In addition to the normal prerequisites, which include a high degree of accuracy, high reliability and a robust design, a checkweigher should include four main features for the food industry. The first is a correct environmental and hygienic design in compliance with international food processing regulations and guidelines. The ingress protection value of all components should reflect the environment in which the checkweigher is deployed; lower levels for dry environments and up to IP69k for harsh environments with regular high pressure washdown cycles. The correct environmental design enables quicker cleaning routines, saving time and costs. Secondly the system should have flexibility in product handling, allowing uncomplicated deployment in different packaging lines, simplicity of integration into existing packaging lines and the ability to be quickly adjusted, allowing a wide range of different products to be weighed - thus minimising downtime on product changeovers. The third key feature should be a user-friendly HMI and service friendly design. An intuitive, clear and easy to understand multilingual menu system on a large and easy to read touchscreen monitor, reduces operator errors and saves time during product changeovers, thereby minimising downtime. Clear open lines of sight to components requiring regular service and easy access to all wear parts, including toolless conveyor belt replacement, both reduce planned service downtime events. Finally the checkweigher should have extensive connectivity solutions to enable the availability of all production data and statistical information in real-time within the local network, giving production and quality managers access to review all relevant data from their desks. This allows for rapid response to problems and facilitates preventive measures, thereby minimising downtime.

Dieter Conzelmann. Bizerba is not limited to the sale of standard products; we design individual system solutions according to specific customer requirements. The new checkweigher generation CWE was developed in order to optimise quality assurance for packaged products. Our 'application engineering team' ensures that the CWE is flexibly integrated into already existing production lines. It can be connected directly to cutting machines, filling machines and multiple-head scales. Thanks to the modular design, the belt size, transport height and direction of travel can be varied.

If the customer also uses the software _statistics.BRAIN, then an efficient system solution is created, which can be made transparent for the production management of all processes - whether in incoming or outgoing goods or in production. The requirements applied to the hygiene design of the checkweigher are also many and varied. In order to be able to save on costs, it must be possible to use the checkweigher in both dry and 'non-cleaning' areas and it must fulfil 'washdown' requirements. We are constantly working on concepts to make cleaning in hygienic zones simpler.

Steve Jones. In addition to standard checkweigher features such as accuracy, ease of use etc the value of a checkweigher can be extended from primarily a legal reporting requirement, to a complete packaging line optimisation tool.

This value extension is achieved through application of information technology, enabling the checkweigher to be used as a 'packing line' data capture system. The information produced by the checkweigher can automatically populate a 'management information system' (MIS); this MIS directly reports performance statistics to decision makers who can instigate corrective action as appropriate.

One such system, the Ishida Data Capture System (IDCS) provides the customer with the option to capture and analyse data from up to 100 packing lines simultaneously, enabling the performance of any individual line to be constantly monitored and the ability to compare line efficiencies throughout the packing hall.

To ensure that the output of this MIS can be easily accessed the IDCS architecture is similar to that of a website. The end result is that any network user who can access the central IDCS server can access the full power of the in-built reporting. This feature even enables managers away from the plant to access line performance data through a suitable VPN link.

In our tough business environment, keeping costs under control is absolutely vital. What role do checkweighing solutions have in helping food producers to remain as profitable as possible?
GS. One of the most important savings - or ways of keeping costs under control - can be achieved when connecting a checkweigher to a filler to reduce overfilling or unnecessary product giveaway thereby saving valuable raw material. Feedback to filler control software can ensure that negative filler tendencies will be corrected by signalling the required adjustment to the filler, so that fill levels remain within the acceptable tolerances - or even ensure that the mean fill level is kept as close to the target weight as possible.

Furthermore, a checkweigher can be used as a central data capture system to improve quality and profitability through detailed production analysis, records for security, compliance and documentation, ensuring that processes are under control.

The fact that a checkweigher is very often used as the final piece of equipment in a production line makes it ideal for capturing valuable data when calculating OEE (Overall Equipment Effectiveness).

DC. Whether it is at goods incoming, production or goods outgoing, no company in the filling industry can afford to over- or under-fill. Under-filling is forbidden by law and also damages the company's image. Even slight over-filling can lead to substantial losses of material.

Companies that have, up to now, merely carried out random tests with small scales, can use the checkweigher to ensure that no over- or under-filled packs leave production. It weighs and classifies packs according to freely defined or legally prescribed weight classes. A detector that recognises metallic impurities can be incorporated as an option. In the case of weight deviations or impurities, pushers remove the deficient packs.

Production lines must also work with a maximum throughput. Combined with the software _statistics.BRAIN, the production management can optimise processes and produce long-term statistics. In addition to FPV-conformant random testing checks, the software offers time-related statistics on materials, machines, batches, layers and alarm signals. Trends can thus be swiftly identified. Due to consistent optimisation of the processes, costly over-filling, reworking and rejection are reduced. Thanks to unique teaching routines, products can be started independently at any time without subsequent testing by the weights and measures authorities. The advantages are clear: targeted cost savings, high customer satisfaction, fewer downtimes, more transparency and growing revenue.

SJ. From a users perspective an effective average weight packing operation is the ideal scenario. By using the checkweigher as an MIS data source and making the integral reports, graphs and tables easily and directly accessible to management staff, immediate corrective action can be taken to address efficiency issues as they arise. The 'real time' aspect of the MIS could depict excessive giveaway, which could be automatically addressed upstream by use of checkweigher feedback, (dependant upon upstream dosing equipment), or if there are efficiency problems caused by unscheduled downtime the root cause can be identified and addressed.

The Ishida IDCS can be configured to monitor OEE with individual acceptability thresholds set by the user for OEE and the three contributory operational metrics (availability, quality and performance). If the line operates at a level below the defined user limit, this is immediately reported. This information clearly puts the user in full control of their process.

IL. Checkweighers take on several roles. The most evident is to check the weight of individual products and to detect faulty weights for reject. Each weight reading is then recorded and used to build a comprehensive production run statistic. This is a fair and impartial base used to verify the quality of the production process itself; for both efficiency and economy. The benefit to the end user is clear: the better the accuracy (weight reading) of the checkweigher the more precise and reliable is the interpretation of the result. If food producers combine these weight readings with a mean value regulation (feedback to the upstream filling machine) they can significantly reduce the unavoidable product give away to a minimum. Such a combination will pay off quickly in  production. Furthermore the manufacturer now has verification of their production process, which will help to build trust with the big supermarket chains and to safeguard their reputation at the same time.

Quality control and safety are of paramount importance in the food industry. How can checkweighers help to guarantee that all products meet the necessary standards?
DC. Depending on the packing, environment and customer-specific requirements, the system reaches a belt speed of up to 120 metres per second in a weighing and measuring range of 10 grams to 15 kilograms. Combined with the software _statistics.BRAIN, the production management can process the data centrally. In the case of deviations, the respective employee on-site can intervene directly in the production process, thereby optimising the throughput and reducing disagreeable reworking and the proportion of rejects. An additional discharge device can directly reject from the production products that are under- or over-filled. Data logs can be automatically saved, sent or manually called, in accordance with the EU regulation 178/2002 for the traceability of goods. All data can be printed out and saved onto memo-card or USB stick. This interruption-free documentation of the weight values makes the checkweigher an ideal quality assurance instrument for the foodstuff industry.

SJ. The concept of quality control is central to checkweigher use. With the option of setting the system to work in average weight mode the system automatically ensures legislative compliance. To extend the functionality to include contamination detection requires integration of a metal detector or X-Ray device.

In addition to combined checkweighing / metal detection / X-Ray capability some retailers also specify reject confirmation. The concept of reject confirmation is fundamentally to ensure that packs which are not fit for sale are guaranteed to be rejected.      

Systems requiring reject confirmation have numerous integral fail safe features (Bin Full, Failure to reject, Low air pressure to name but a few), if any of these conditions are activated the system stops immediately. To constantly validate these features a 'built in self test' capability is included, ensuring that critical safety measures are functional, for example a test for bin full and failure to reject.

IL. Once the checkweigher has been designed, built and installed correctly, it will operate 24/7 without complaining or getting tired. In other words, it will weigh each product and complete a 100 percent inline check of production. The food manufacturer can set specific limits, or work to the legal requirements with any pack not compliant to these limits being automatically rejected. But OCS checkweighers can do much more. For instance, when consecutive errors occur the checkweigher can give an alarm for the operator to check the production process or production can be set up to completely stop until further investigation is carried out. Other than spot checks, the food producer has real time information at hand, which helps to avoid time and cost intensive follow-up inspections. A checkweigher can also be combined with a contamination inspection (e.g. metal detector or x-ray scanner). This would be space saving and links two product inspections into one process (with two different rejections) but one statistic.

GS. All checkweighers should be pre-programmed with the allowable weight deviations and tolerances as laid down in local packaging regulations. As soon as a new product is selected then the checkweigher will automatically calculate the zone limits for these products to guarantee that no out-of-tolerance products are allowed to pass. The checkweigher must also comply with all local Weights and Measures regulations and be capable of being officially calibrated in respect of weight or volume measurement depending on the products being produced.

Newer checkweigher models are also available in combination with metal detectors and X-ray systems. These combination systems guarantee that foreign bodies are readily detected. In all checkweighing and combination systems the sensitivity, accuracy and reliability of the system are paramount in ensuring the best quality and safety of all products produced.

How is innovative technology making checkweighers more efficient? Do you foresee any major technological developments in the near future?
SJ. In considering how 'state-of-the-art' technology developments can be applied to benefit checkweigher users, key areas will be increased throughput, improved accuracy, simplified user interfaces and further extension of the use of end-of-line data capture to optimise the overall process.

Specifically it's likely that enhanced performance digital load cells, extended use of forced balance techniques, application specific filtering algorithms, more touch screen technology and sophisticated mechanical engineering will enhance the performance of today's machines to meet the challenges of the future.

In association with engineering enhancements; advanced materials and manufacturing processes will lead to more flexibility in provision of customised conveyor sizes and simplified high-speed reject stations.

Finally, the checkweigher 'value extension' opportunity should not be under estimated. Positioned towards the end of the packing line, it is ideally located to report upon full line performance.

IL. Innovative technology is the basis for creative solutions in allowing reliable and well performing checkweighers. At OCS we have developed our own innovative Weigh Cells that are second to none. OCS is proud to have total control over the weighing process at any time and circumstance. Therefore we can concentrate on product handling, which we believe comprises of an 80 percent success rate in achieving precise checkweighing. Speaking about ownership of key technology, we have developed in-house our own servo drives driving our own patented conveyors built absolute stable and in weight saving construction. This system is controlled by our own industrial PCs. As a consequence we are also owners of a long lasting spare parts supply ­- another safeguard to protect the investment.

For the future we see an even stronger demand for high performing checkweighers that are built to support increased efficiency levels and capable of handling new product packaging designs. At OCS we welcome future opportunities as we have the expertise and equipment to provide the right solution.

GS. Innovative new technology advances are leading to the production of better quality and higher precision weighing systems through the improvement of construction materials for motors, conveyors, electronics and weighcell technology. The checkweighing manufacturers with large R&D departments are much better able to take advantage of these advances. I foresee three major technical advances in the near future. Firstly in the field of weighcell technology with higher sample rates, better vibration compensation and higher resolution for faster and more accurate weighing. Secondly, advances in central data capture solutions and connectivity to OPC (OLE for Process Control) servers and ERP (Enterprise Resource Planning) systems. The third area of technical innovation will be the intelligent inclusion of additional components including metal detectors and x-ray systems for greater product safety, track and trace marking and verification equipment as well as RFID.

DC. The handling of the checkweigher is extremely simple: the operator sees the current belt speed of up to 170 metres per minute on a touch-screen, as well as a histogram of the last n-packs and their Gaußian distribution. In the case of deviations, the employee on site can intervene directly in the production process. Due to the CWE multi-display concept, several control units can be set up at different points on the production line, as remote indications for example.

The CWE line is a modular building-block system that adapts to the specific requirements of the already existing production line, such as with different belt sizes at appropriate transport height and direction of travel. Constructed from stainless steel in accordance with the latest machine guidelines, protection class IP 65, the CWE fulfils the high requirements for maintenance, safety and handling. The belt body and belt rapid-change system ensures quick and easy cleaning. We are constantly working on concepts to make cleaning in hygienic zones simpler. We are also further developing the integration of additional components: such as the incorporation of a line divider, a line converger, efficient rejection systems and other test systems like metal detectors and x-ray scanners.

The panel

After studying Industrial Engineering, Ingolf Latz completed his MBA and started his career in sales. He joined OCS Checkweighers in 1999, where he has succeeded within the company in various positions. He currently holds the position of International Sales Director, which involves managing global sales for OCS Checkweighers.

Gunter Schilpp is the Marketing Manager of METTLER TOLEDO Garvens responsible for global marketing activities in the field of checkweighing applications and solutions. With over 14 years experience in the packaging industry he is responsible in transforming complex technical issues into clear customer value messages, global solution launches, market strategy development, research and checkweighing development collaboration as well as brand strengthening and marketing strategy creation.

Dieter Conzelmann is Director Industry Solutions Market and President of Bizerba Solutions Inc. He studied information technology in Stuttgart/Esslingen and began his employment at Bizerba GmbH & Co. KG in 1989 as a development engineer. Since 1999, he has been responsible for managing the Industry Solutions division, and since 2008 he has also been responsible for the business management of Bizerba Solutions Inc. in the USA.

Steve Jones is General Manager, Product Group Marketing for Ishida Europe Ltd. Initially from a electronic engineering background he has extensive experience in product management and marketing of 'high tech' capital equipment to diverse sectors such as aerospace, semiconductor manufacturing equipment and more recently food packaging.