On the automated packaging production line for ton bags (container bags), the filling process frequently encounters material jamming (commonly known as "bridge formation"), which not only significantly reduces production efficiency but also causes abnormal equipment load and even triggers mechanical failures. When the packaging scale experiences difficulties in discharging materials, intermittent discharging or complete stagnation during the filling process, it is usually not caused by a single factor, but rather the result of the combined effects of material physical properties, equipment operating conditions, and parameter settings.
Below, from four core dimensions, we will conduct a detailed analysis for you of the common causes leading to frequent material jams in packaging scales and the corresponding solutions:
1. The physical properties and conditions of the materials themselves have an impact.
The properties of the materials are the fundamental cause of the difficulty in material cutting. In many cases, the pre-treatment standards for the materials by the production line differ from the actual incoming materials.
• Moisture content and viscosity changes: This is a very common cause. If the moisture content of the material is too high, or if the material has strong adsorption and viscosity properties, it is very likely to form clumps and stick together in the silo or the hopper. As the size of the clumps increases, it will block the discharge channel.
• Particle shape and hardness: The material particles are irregular in shape, too finely crushed, or have high hardness with sharp edges. During frequent friction and accumulation processes, they are prone to form a compact arched structure (i.e., "bridges").
• Electrostatic adsorption effect: Certain lightweight and dry powder materials are prone to generating static electricity during high-speed flow and friction, causing the materials to adhere to the inner walls of the silo or the inner walls of the discharge port, resulting in poor discharge.
II. Mechanical Structure of Equipment and Wear Condition of Components
If the mechanical components of the packaging scale become aged or worn out, they will directly disrupt the original smooth feeding mechanism.
• Degradation of the breaking/conveying system efficiency: Most ton-scale scales currently come equipped with pneumatic break拱 devices or fluidized bed systems. If the air pressure of these pneumatic components is insufficient, there is leakage in the pipelines, or the air vents on the fluidization plates are blocked by foreign objects, the materials will not be able to achieve sufficient fluidity, and it is highly likely that dead material areas will form.
• Wear of internal liner and discharge port: After long-term operation, the inner wall of the silo or the triangular-shaped area at the discharge port may experience wear and deformation, becoming uneven. This rough surface will significantly increase the friction of the materials, creating a breeding ground for material blockage.
• Defect in transition connection: The soft connection (such as a rubber flexible bag) between the hopper and the lower bagger or feeding port may be too short, improperly installed, or have creases. When the material falls at high speed, it will be physically blocked.
III. Control System Parameters and Logic Settings
If the parameters of the automated equipment are not set in accordance with the actual material conditions, it often leads to the equipment operating on the "edge of dilemma".
• Imbalance in feeding logic: The feeding speed is usually divided into two stages: fast addition and slow addition. If the fast addition stage is closed too early, the material will not be compactly piled at the bottom; or if the slow addition stage responds sluggishly, resulting in an excessive drop height above the discharge outlet, it may alter the flow pattern of the material.
• Pneumatic valve action lag: For the butterfly valves or gate valves that control the input and output, if the cylinder response speed is slow, the opening is not complete (there is a half-open dead zone), or the electromagnetic valve is sluggish in response, it will artificially cause blockage in the output channel.
• Weighing sensor signal interference: If the sensor is disturbed by external vibrations or if the filtering coefficient is set improperly, it may cause the instrument to misjudge the material level height and prematurely terminate the discharging command.
IV. Factors of On-site Environment and Operating Procedures
Minor changes in the production environment are often overlooked, but they are frequently the cause of intermittent failures.
• Environmental temperature and humidity fluctuations: Especially in seasons with significant temperature differences between morning and evening, condensation water is likely to form inside the silo. This will instantly alter the micro-environment of the materials, causing the previously smooth materials to suddenly become sticky.
• Poor air quality: The pneumatic system of the packaging scale has strict requirements for air quality. If the moisture content in the compressed air provided by the air compressor is too high, it will not only corrode the valves but also freeze in the solenoid valves or cylinders in low-temperature environments, causing the valves to malfunction.
• Manual operation habit: During the process of loading materials and replenishing inventory, if the operator fails to break up large pieces of materials before pouring them in, or if the loader brings in large foreign objects when scooping materials, these large pieces are highly likely to get stuck above the discharge outlet.
V. Systematic Investigation and Optimization Suggestions
In view of the above reasons, the following measures are recommended for a systematic investigation:
Source control: Strengthen incoming material inspection, strictly control the moisture content and particle size distribution of the materials; if necessary, add auxiliary equipment such as forced stirring or drying intervention at the front end of the production line.
2. Mechanical maintenance: Regularly polish the inner walls of the silo, inspect and clear the air passage for dislodging the damper; replace the severely worn liners and outlet components; ensure that the soft connection is in a naturally relaxed state.
3. Parameter fine-tuning: Attempt to adjust the feeding speed curve, appropriately extend the duration of the slow feeding stage, and reduce the impact of the drop in the threshold; check and calibrate the opening degree of the valves.
4. Environmental Assurance: Install air drying filters to ensure that the air used by pneumatic components is clean and dry; maintain good ventilation in the production workshop to reduce dust accumulation and the impact of moisture.
By conducting a comprehensive diagnosis from the four aspects of materials, equipment, parameters and environment, it is usually possible to accurately identify the root cause of the jamming problem in the bag packaging scale, thereby restoring the smooth operation of the production line.
