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Packaging in Bags - How Symach's Solutions Redefine the Palletizing Industry

Nov 03, 2023

Depending on the product, the market and the transport distance, there is an infinite variety and complexity of bags in terms of size, material, shape and closing system.  Bag packaging line manufacturers have adapted to their customers' demands by responding to this variety with flexibility.

Today the packaging machines, for most manufacturers, have reached a high level of maturity. By maturity we mean reliability, low maintenance, productivity without stoppages, optimal ergonomics for operators, precision of the dosing machines, quality of the bag closures, pallets and filming, with minimal changeover times for recipes and formats, all at speeds close to those of the product flow. In addition, data can be exported and integrated into company systems for production control and traceability purposes.

Symach BV, based in the Netherlands, has been manufacturing palletizers for some 30 years. After the acquisition of the Dutch company by the Barry Wehmiller Group in 2015 Symach manufactures complete packaging lines, including fillers, baggers, weight control and metal detection systems, palletizers and filmers.

Symach's weighers are all about accuracy and speed

When the product has an easy flow, such as seeds, pet food, sugar, rice, the feeder can be fed by gravity. The continuity of the flow is such that no error will be detected during weighing. On the other hand, when the product has a difficult flow, such as horse feed, products that agglomerate, where the continuity of the flow is not obvious, it will be necessary to equalize the product. Product levelling is generally carried out by a belt that collects the product in a constrained manner under the hopper and sends it to the dosing machine after levelling it under a blade. The product flow is then constant without agglomeration or clumps. The weighing is then made precise.

Symach manufactures these two types of gravity and belt dosing machines with display of the rates (about twenty doses per minute) with an average of 0g compared to the set point and a standard deviation of 15g on doses of 25 kg. Symach dosing machines can be certified by the legal metrology services. The weighing data can be exported to an ERP system or printed on labels at the palletizer outlet, by batch.

Bagging and diversity

Bagging is certainly the most complex part of the packaging process as it has to take into account the diversity of the bags and their closing and identification system.

The size of the bags is one of the first criteria of flexibility that we can attribute to the Symach bagging machine. The bagging mouth is designed to handle both small and large bags; in fact, with a density of 0.5kg/l, the Fillstar bagger can bag contents from 2.5kg to 50kg. The format changeover is done via the control screen in a matter of seconds and without having to change the mouth.

The Symach bagging machines can work with preformed open mouth bags and from rolls of tubes.

Before closing, the bag will go through different stages, it can be printed flat before being filled or it can receive one or more labels.

Symach integrates its own labelling machines or those of the customer. As the bags move flat on a belt, an X axis, the printers or label applicators move on a Y axis, the labels are stuck on in a very precise way. The identification systems placed in this module can be an inkjet printing solution, a laser marking, a lick printing or a straight applicator.

The bag received under the mouth will be checked for horizontality. This is important in order to achieve a perfectly horizontal closure, whether it is sealing or sewing, or even more so when a fold has to be made. If a bag is not considered horizontal, it will be ejected before being filled.

The bags, especially plastic, PE and PE/PET bags, can be equipped with slider, zipper, Velcro, depending on the marketing and market trends. These bags will also be checked before filling. If a bag is not correctly opened after a few attempts it will also be ejected;

During filling and in order to optimize speed, the bagging mouth includes an internal mouth at mid-height which allows product to be retained if the bag is not ready, or allows product to be sent from a limited height to avoid tearing a bag when it is made of paper. This fore-mouth also increases the level of nitrogen and expels oxygen from the core when the bags need to be inerted.

Symach bagging machines are designed in modules. After filling, the bag will go through different stages in the bagger depending on its characteristics or those required by the customer, such as de-aeration of the bag to give it a better shape or fine nitrogen adjustment, a sealing module which can be single or double, a handle cutting module, a folding module before sewing, a sewing module, a pinch top closing module, and often a bag turner or pusher depending on the line layout. The modular design allows the bagging machine to be upgraded with a later module if the customer wishes to add a sealing or inerting function not initially planned.

The Symach bagging machines are controlled from two different locations to limit the need for operators to travel and can be remotely controlled via a tablet. The maintenance manager is assisted in his duties by the display of maintenance alarms.

 Symach palletizers

Symach palletizers are all Cartesian in operation. The bags are placed on the pallet on a plane established by the operator in X and Y. This solution allows the bags to overlap and therefore improve the load. Overlapping also allows the space taken up on the pallet to be optimized and therefore the overflow of bags to be controlled.

In addition to this classic operating solution, Symach forces the bags, during palletization, to remain within a template throughout the stacking process. The result is perfect, the bags are stacked flush with the pallet. The pallets leave the palletizer perfectly rectangular.

In terms of output, the solution is applied in different motorizations, ranging from 15 bags per minute to 46 bags per minute.

The palletizers can be supplemented with options such as film or cardboard protective film dispensers, layer pads, pallet bottom trays, the possibility of palletizing bundles, pallet weighing, etc.

 Wrapping, the guarantee of load stability.

The complete line ends with a pallet wrapping solution to guarantee load stability.

On leaving the palletizer, the pallet can be fitted with a protective cover or a real rainproof solution. Once the cover is removed, the pallet is wrapped in stretch film or net depending on the product. Symach stretch wrapping machines are either rotary table or rotary arm machines. The programs are flexible, it is possible to set different numbers of turns, at the top of the pallet, but also at the bottom, with an overlapping of film also customizable. The choice will be made according to the layout, speed and stability to be achieved.

 Intelligent packing lines, preventive maintenance, traceability, ERP

Maintenance, traceability, statistics, all Symach equipment is connected and can communicate intelligently with other equipment or servers.

In terms of maintenance, all the machines are equipped with movement counters and can therefore offer preventive maintenance by sending alarms, such as changing a cylinder, belt, etc. These alarms can only be acknowledged by the maintenance manager. They allow intervention before any breakdown and therefore blockage of the packaging.

In addition to the screens, the machines can be remotely controlled via tablet or computer, provided that safety conditions are met. The screen of the bagging machine or palletizer is displayed on a remote screen.

In this way, Symach can take control of the equipment remotely on request of the personnel, 24 hours a day, and carry out the first diagnostics and solve breakdowns.

In the context of a constant demand for traceability, from the labelling, filling, sealing and weight control stages to the metal detector, the bags can be tracked and identified with the information received at each stage and transmitted to the ERP, pallet printer or other traceability server.