The Checkweigher— Knowledge Is Power

Monday, September 18th, 2017

The checkweigher’s role as the ‘policeman’ of the packing line is evolving to one where it can make a significant contribution to overall efficiency and profitability, says Philip Grove, product manager, Ishida Europe.

The checkweigher has often been viewed as a necessary purchase. Compliance regulations—whether demanded by the end customer or by legislation—require a final weight check to be carried out to ensure each pack meets the correct average or minimum weight requirements.

Given the renowned accuracy of today’s multihead weighers, there are many who might argue that the role of the checkweigher has almost become superfluous. However, this approach tends to oversimplify the situation.

A multihead weigher can deliver the correct target weight, time after time. What it cannot guarantee is that the weighed product subsequently reaches the final pack intact—any problems with the distribution or filling system, or a tear in a pack that leads to product falling out, will not be picked up by the weigher. And on increasingly automated lines, there may not be personnel on hand to spot such mishaps immediately. To avoid these situations turning into major problems, the checkweigher is invaluable.

Equally important, compliance is just one requirement that companies need to take into consideration on their lines. In today’s highly competitive markets, the need to maximise efficiencies at every stage of production and packing remains critical.

A Growing Need For Versatile Equipment

While this is hardly a new concept, the external pressures on food manufacturers’ bottom lines are intensifying, driven in particular by the move among retailers to more and more own-label products. This is a familiar situation in the UK market, and this is now growing apace too in many other markets throughout Asia, the US and Europe.

While own-label products initially competed on their lower prices compared to mainstream brands, as consumer tastes have become both more sophisticated and demanding, quality has taken equal prominence. Consumers now seek products that meet both their quality and value expectations. The same trend can be seen in the emergence of the discount chains in recent years, where quality is now as important as price to their value proposition.

For food manufacturers, this growth in own-label products has led to a significant increase in the number of product lines they need to have. Each product will have slightly different specifications and standards. This in turn means shorter production runs and many more line changeovers. Meanwhile, the drive for value pricing for the end consumer further underlines the necessity for manufacturers to maximise throughput and efficiencies.

The result of this is that factories are becoming more and more automated, as companies seek to adopt the principles of Industry 4.0 and lean manufacturing. In truth, much of the thinking behind these concepts has been around for many years as production and packing lines have become more and more integrated—individual pieces of equipment are commonly linked together and able to talk to each other to help maximise speeds and transfer of product throughout the operation.

Nevertheless, however well-designed and integrated a line may be, the fact that it is made up of different pieces of equipment means that it is unlikely to operate consistently at its peak rate. There will always be slight variations or occasional hold-ups at some point which may affect its overall performance. This means that the ability to spot unplanned downtime and be able to react to them as quickly as possible becomes the critical factor in delivering the highest level of efficiencies.

Checkweighers Take On A More Important Role

In an automated world with fewer opportunities for human intervention, it is often down to the machinery on the line to help deliver the necessary level of monitoring.

This is where the checkweigher is able to take on an increasingly important role. Many of today’s models have the software capability to deliver a huge amount of valuable information that enables companies to take instant action to improve the performance or efficiency of their lines, so much so that payback on this investment can be extremely fast.

Significantly, this data is instantly available and accessible—it does not require the information to be downloaded and then manually assessed in order for a report to be compiled. Anyone with the appropriate level of authorised access can view this at any time—and from anywhere, as the information can be delivered remotely. And just as significant, this remote access means information can quickly be compiled and compared between different lines, even at different locations.

In this way, the software plays a valuable role in assessing a line’s Overall Equipment Effectiveness (OEE) by constantly monitoring it in terms of availability (the amount of available time the production line actually runs for), performance (expected versus actual number of packs being produced) and quality (the percentage of packs produced that fall within the required quality parameters).

The combination of these three elements provides an OEE percentage that uniquely identifies how efficient a production line is running, and can show this value for a factory, a production line, or a particular product at any time frame, in order to identify potential areas of improvement.

This ability to analyse the data in order to suggest improvements is a significant benefit. For example, information on overweight products could highlight that a chocolate bar is consistently two grams over the required weight. This may suggest that the enrober is putting too much chocolate on each bar. For a ready meal or a bag of mixed nuts, the same overweight each time might identify too much of a particular ingredient is being added.

Analysing In Detail

While these excessive weights might be the result of a fault in another piece of equipment, they could also uncover the fact that the line is running at too high a speed for it to deliver maximum efficiencies. It is important to remember that the fastest speeds do not always equate to the highest efficiencies. Giveaway is amplified by the amount of product going through the line. If, by lowering the overall speed, the amount of giveaway is significantly reduced, this would ultimately deliver a much better overall efficiency rate.

This is a particularly important consideration in light of another trend in the retail sector where manufacturers are now reducing the weight of their products—either to counter the increasing costs of raw materials and to keep products within a particular retail price point, or to meet demand for smaller portion sizes in the drive to minimise food waste or tackle obesity. In either scenario, the lower the target weight, the greater the potential for giveaway unless this is carefully monitored and appropriate action is taken.

Product giveaway also has other implications. Overweight packs that are detected may provide an opportunity for the product to be re-packed—but the cost of wasted packaging cannot be recovered. Again, this can be a particular issue where smaller pack weights mean more packs being produced and can have a significant effect on the bottom line in competitive markets.

In many cases, the impact of a slight dip in performance by one piece of equipment on the line may be minimal. However, if this is repeated in two or three machines at the same time, the cumulative effect may be considerable.

In essence, therefore, the data that can be derived from a checkweigher provides a constant and real-time health check on all areas of the line. It also enables accurate comparisons to be carried out between different lines. This can be valuable where the lines are in different locations—if individual factories are undertaking their own assessments, then how they report their figures or interpret the data may differ from location to location, even if they are working toward the same set of KPIs. Using the checkweighers to supply and interpret the data means everyone is working to the same standards.

Ensuring All Stays Compliant

The sort of savings that can be generated by effective monitoring can be considerable. In one of our recent installations, a pet food manufacturer packing around 700 cans of product per minute on an eight-hour shift saw a payback on the investment within a few months through the ability to better control the amount of raw ingredients that went into each can.

For any successful food manufacturer, high levels of data are essential to the smooth and efficient running of their operations. And crucial to their ability to make the most of the information is how it is accessed and how it is interpreted.

Today’s checkweighers can provide consistent, real-time detail on the running of all factory lines in all locations in a form that is easy to view at any time by any authorised person, and which can make valuable comparisons between different parts of the business.

The checkweigher will always be required for its ‘policeman’ role that ensures businesses are compliant with all relevant weights and measures requirements. However, in a world where everyone is always seeking added-value from their products and services, the modern checkweighers’ ability to deliver high levels of relevant and pertinent data provides the detailed knowledge that will enable businesses to improve their OEE. In this way, they can compete effectively and maximise their profitability even in the face of intense competition.