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Weighing and packaging fragile biscuits is not easy; the most challenging part of the process is avoiding product breakage. To find out how these processes can be made more efficient, cheaper and faster, WorldBakers talked with Torsten Giese, marketing manager – PR + Exhibitions at Ishida Europe Ltd.  

By Ioana Oancea

Avoiding biscuit breakage is a challenge that must be addressed during handling, because most of the people want appealing products, with a few exceptions when broken biscuits are intentionally sold on the shelves (at a much lower price).

Timing is the first factor that helps processes inside the weighing machine run smoothly; each stage needs to be perfectly timed between the infeed, the weighing process and the discharge process, then the transfer from the discharge chutes into the packaging machine, Giese explains. “You have to optimize [all timings] to allow a smooth product flow through the weighing machine and into the packaging machine, not have any gaps,” Giese tells us.

In addition, the producer needs to make sure that the biscuits are gliding rather than falling from the infeed to the discharge system of the weighing machine. For this, the hoppers need to be curved or angled so that the product falls gently in a low angle. For Ishida machines, the stainless-steel hoppers contain Bancollan, a special material that helps cushion the biscuits during their transfer into the packaging system. “Bancollan liners are very effective cushioning solution for fragile biscuits,” Giese explains the process.

After products pass through the radial feeder (which also needs to be set up to minimize product breakage), they fall into hoppers fitted out with Bancollan, where they are both stabilized, in the pool hoppers, and weighed, in the weigh hoppers. The next step is going into shallow (42 degree) angle discharge chutes, also lined with Bancollan, to further protect the biscuits as they transfer towards the packaging machine.

At the bottom of these discharge chutes, there is often a ring shutter, which is a round device that goes up and down by about 10 cm and stops the product briefly in the discharge chutes and then transfers the biscuits into either a holding (timing) hoper or directly into the packaging machine. The ring shutter is timed with the discharging weigh hoppers, so that the product transfer is optimized, thus further aiding gentle product handling.

A Quest of Speed

The second challenge in weighing and packing fragile biscuits is the speed of the machine, the Ishida specialist says.

“Everything has to be done to achieve a balance between speed and gentle handling”, Giese adds. 

When operating with a higher speed, the product needs to go through the weighing and packing machine much quicker. When this happens, the product can be damaged more easily because biscuits may hit each or the weigher’s contact parts.

The Changeover Process

Biscuit producers have to be clever with product changeovers, says the Ishida specialist, because sometimes using the same machine for very different types of biscuits poses more challenges than benefits.

Circular machines can handle a bigger variety of products – ranging from small to large and from the light to heavy, or from fragile to sturdy biscuits.

If a producer chooses to run different products within that range through the same weighing/packaging line, they need to look at what hopper sizes will provide the best versatility. A three-liter machine, which means that each hopper has a capacity of three liters, can handle most applications for biscuits. For example, a half-liter machine, which gives higher speed, will struggle with larger biscuits. On the other hand, a five-liter machine is suitable for big bags (for supermarkets, for the Christmas season, or for the foodservice sector).

In this respect, Ishida’s machines have a function that can help: the manufacturer doesn’t need larger hoppers to increase capacity because the equipment can be set to “double dump”– it can weigh, for example, 750g two times to fill a bag with 1.5kg of biscuits. The carton or bag will remain open as the machine will make two or even three discharges. 

Another issue that might come with changeovers to another type of product is the cleaning of the weigher’s contact parts. For example, Ishida machines can be cleaned using compressed air (this can take less than 15 minutes), so the biscuit manufacturer doesn’t need to take them off until a major clean down at shift end.

“After the cleaning process, the producer must manually select the next product type to go through on the remote-control unit, since many of our weighing machines have a capacity of 200 different recipes,” explains the specialist.

The difficult part comes when the machine runs an allergenic product, like nuts. In this case, the hoppers need to be taken off and thoroughly cleaned.

“For nuts and halal products you have very strict product handling regimes.”

Solutions for Very Fragile Biscuits

For very fragile and dusty biscuits, Ishida proposes a linear weighing system.  This system is suitable for small biscuits and small target weights, for example 15 grams of biscuits per pack, which is ideal for higher-value products. The difference for this type of machine is that the hoppers are in a linear configuration. After the product has been weighed in the linearly arranged weigh hoppers, the products slide down in a linear discharge chute, not a circular one. Here, the system doesn’t need a ring shutter, because the product is transferred very gently. Depending on the biscuit being handled, these linear weighers operate at slightly lower speeds than the circulator version, but a 12 head linear model can easily operate at 80 weighments / packs per minute and still achieve an impressive low breakage level. 

Related articles: 

Gently Ishida weighing for wafer biscuits, installed at producing plant in Macedonia 

Case study: Ishida multihead weigher increased production efficiency for Italian confectionery manufacturer 

Ishida Launches Multihead Weigher for Bakery Products  

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