Automatic Feed Bagging Scale
In feed production, transferring the finished product into bags is only part of the packaging process. Each bag must also be filled as close as possible to the target weight, while the bagging line must be capable of keeping up with the overall production capacity. An automatic feed bagging scale combines weighing and filling operations at this stage.
Feed mills may need to bag products with very different flow characteristics, including pellets, mash feed, granular products, premixes and flakes. However, not every product can be fed into the weighing system in the same way. Free-flowing pellets behave differently from fine powdery feed. For this reason, KARDEV bagging systems can be configured with gravity, belt or screw feeding depending on the characteristics of the product.
How Does an Automatic Feed Bagging Scale Work?
The bagging process begins when the product is transferred from the upper hopper into the weighing system. Free-flowing products such as pellets and less free-flowing products such as mash feed require different feeding methods. Depending on the product characteristics, gravity, belt or screw feeding can be used.
During filling, the weight is continuously monitored by load cells. The product is initially fed at a high rate. As the target weight is approached, the feed rate is reduced and the system switches to the fine-filling stage.
Once the target weight is reached, the product flow is stopped. In KARDEV’s net weighing system, the product is weighed in the weighing hopper before entering the bag. The bottom gate then opens and the weighed product is discharged into the bag secured at the filling spout. A pneumatic bag-clamping system holds the bag in position during filling.
How Is the Feeding System Selected According to the Product?
The same feeding method is not suitable for every product. Product flowability, particle structure and sensitivity to breakage should be considered when selecting the appropriate system.
Gravity Feeding
Pellets, grains and other free-flowing products can be transferred into the weighing hopper by gravity. In this configuration, an additional belt or screw feeder is not required to move the product.
However, the product must actually flow freely. If bridging or irregular flow occurs at the hopper outlet, excessive product may suddenly enter the scale after a period of restricted flow. Therefore, gravity feeding should not be selected solely because a product is classified as granular.
Belt-Fed Bagging Scale
Belt feeding is used when the product flow needs to be controlled mechanically. It can be considered for powders and granular products as well as pellets and other products that may be sensitive to breakage.
Moving the product on a belt provides controlled feeding and makes this configuration suitable for a range of feed products with different characteristics.
Screw-Fed Bagging Scale
Screw feeding can be used for flour, mash feed and other fine products that do not flow freely. The rotating screw transfers the product into the weighing section at a controlled rate.
The enclosed construction can also help reduce the release of dusty material into the surrounding working area.
Factors Affecting Bagging Accuracy
Even when the same target weight is selected, different products may not behave identically during weighing. Changes in product flow affect both filling time and the amount of material that continues to enter the weighing hopper after feeding is stopped. For this reason, weighing accuracy should not be evaluated solely from the scale indicator.
Product Flow Characteristics
Free-flowing products such as pellets and grains generally enter the weighing system more consistently. Fine, lightweight or difficult-flowing products may show greater variations.
If bridging occurs inside the hopper, the flow may decrease temporarily and then suddenly increase. This can cause weight variations between bags.
Coarse and Fine Filling Adjustment
Most of the bag is filled during the coarse-feeding stage. As the target weight is approached, the system switches to fine feeding.
If this transition point is set too late, the target weight may be exceeded. If it is set too early, fine filling takes longer than necessary. The final bag weight may still be correct, but the hourly bagging capacity can decrease.
Material Flow After the Feeder Stops
Stopping the feeder does not immediately stop all material movement. Some product located between the feeding point and the weighing section may continue to fall into the weighing hopper.
The control system must take this additional material into account. This value may also change when the product changes because a free-flowing granular product and a fine powder do not behave in the same way after feeding stops.
Load Cells and Mechanical Connections
Load cells measure the weight applied to the weighing system. Contact between the weighing hopper and another component, restricted mechanical connections or accumulated product can affect the measurement.
Therefore, when a weighing deviation occurs, the mechanical components of the scale should also be inspected before assuming that the load cell needs to be replaced.
Relationship Between Bag Weight and Bagging Capacity
The capacity of an automatic feed bagging scale should not be evaluated only in tons per hour. The selected bag weight also determines how many bagging cycles must be completed per hour.
For example, when the same quantity of product is packed into 25 kg bags instead of 50 kg bags, twice as many bags must be handled.
Each cycle includes weighing, discharging, releasing the filled bag and preparing the next bag. As the number of cycles increases, other equipment in the packaging line becomes increasingly important.
For this reason, the weighing speed of the bagging scale alone does not determine the capacity of the complete bagging line.
Regular Maintenance and Inspection of an Automatic Bagging Scale
Maintenance of an automatic bagging scale involves more than the weighing system itself. Problems with the feeder, weighing hopper, load cells, pneumatic components or bag-clamping mechanism can affect both bagging capacity and weighing accuracy.
Areas through which the product passes should be regularly checked for material accumulation. The weighing hopper should also remain free from unintended contact with the machine frame or other components.
Maintenance requirements on the feeding side depend on the selected system. Belt-fed configurations require inspection of the belt and drive components, while screw-fed systems require inspection of the screw, bearings and drive assembly. In gravity-fed systems, the gates should operate freely and areas susceptible to product accumulation should be checked.
If weight deviation occurs, electronic adjustment should not necessarily be the first step. The zero reading should first be checked while the scale is empty. The weighing hopper should then be inspected for unrestricted movement and residual material. If no mechanical problem is found, calibration and load-cell checks can follow.
KARDEV Custom Automatic Feed Bagging Scale Solutions
When designing a bagging system, the first consideration is how the product flows. Bag weight and required capacity are also important factors in determining the appropriate system configuration.
At KARDEV Makina, gravity, belt and screw feeding options are evaluated according to the characteristics of the product. Equipment upstream and downstream of the scale is also considered during project planning.
The product supply hopper, bag filling height, sewing conveyor and operator working area all affect the final layout. Accurate site dimensions are particularly important when a bagging system is being added to an existing feed mill.
In some applications, the bagging scale itself may have sufficient capacity while bottlenecks occur elsewhere in the packaging section. Therefore, the capacity of the complete system should not be calculated based on the bagging scale alone.
To determine the appropriate automatic feed bagging scale for your project, KARDEV can evaluate the product type, required bag weight, hourly capacity, product flow characteristics and plant layout.
Frequently Asked Questions
What is an automatic feed bagging scale used for?
An automatic feed bagging scale weighs product from the production line to a predetermined target weight and fills it into bags. In feed mills, it is generally installed in the packaging and dispatch section.
Which products can be handled by an automatic feed bagging scale?
The system can be used for pellets, mash feed, granular products, flakes, premixes and various other bulk products. The feeding system is selected according to the flow characteristics of the product.
What is the difference between belt-fed and screw-fed bagging scales?
The main difference is how the product is transferred into the weighing system. Belt feeding moves the product in a controlled manner on a conveyor belt, while screw feeding is particularly suitable for controlled feeding of fine or difficult-flowing products. The appropriate system depends on the physical characteristics of the product.
What factors affect bagging accuracy?
Product flow characteristics, coarse and fine filling settings, material continuing to enter the scale after the feeder stops, load-cell condition and product accumulation around the weighing hopper can all affect weighing accuracy.
Is the capacity the same for 25 kg and 50 kg bags?
No. The number of bagging cycles required for the same tonnage is different. For example, packing 10 tons of product into 25 kg bags requires 400 bagging cycles, while 50 kg bags require 200 cycles. Bag weight therefore has a direct impact on the required bags-per-hour capacity.
Can KARDEV Makina manufacture a custom automatic feed bagging scale?
Yes. KARDEV Makina evaluates the product type, bag weight, required capacity, flow characteristics and plant layout to determine a suitable automatic feed bagging solution.
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