1 Environmental factors and solutions
Many environmental factors can affect the function of dynamic automatic checkweighers. It is important to know that the production environment in which the automatic checkweigher is located will affect the design of the weighing sensor.
1.1 Temperature fluctuations
Most production plants strictly control the temperature, but temperature fluctuations are inevitable. Fluctuations not only affect the way materials behave, but other factors such as ambient humidity can also cause condensation on the weighing sensor, which may enter the weighing sensor and damage its components unless the weighing sensor and its surrounding system are designed to withstand these factors. Cleaning procedures can also cause temperature fluctuations; some weighing sensors cannot operate at high temperatures and require a period of time after cleaning before restarting the system. However, weighing sensors that can handle temperature fluctuations allow immediate startup, reducing the downtime caused by cleaning procedures.
1.2 Airflow
This factor only affects high-precision weighing applications. When the weight is a fraction of a gram, any airflow will cause differences in weighing results. As with temperature fluctuations, mitigation of this environmental factor is largely beyond the control of the system itself. Rather, it is part of the overall climate control of the production plant, and the system itself can also try to protect the weighing surface from air currents, but in general, this factor should be addressed and controlled through production layout rather than any other means.
1.3 Vibration
Any vibration that ends up being transmitted through the weighing surface will affect the weighing result. This vibration is usually caused by other equipment on the production line. Vibration can also be caused by something as small as opening and closing containers near the system. Compensation for vibration depends largely on the system’s frame. The frame needs to be stable and able to absorb environmental vibrations and prevent these vibrations from reaching the weighing sensor. In addition, conveyor designs with smaller, higher-quality rollers and lighter conveyor materials can inherently reduce vibration. For low-frequency vibrations or very fast measurement speeds, the automatic checkweigher will use additional sensors and software tools to appropriately filter out the interference.
1.4 Electronic Interference
It is well known that operating currents generate their own electromagnetic fields, and can also cause frequency interference and other general interference. This can greatly affect the weighing results, especially for more sensitive weighing sensors. The solution to this problem is relatively simple: Proper shielding of electrical components can greatly reduce potential interference, which is a prerequisite for meeting industry standards. Choosing construction materials and systematic wiring can also alleviate this problem. In addition, as with environmental vibration, the weighing software can identify residual interference and compensate for it when calculating the final result.
2 Packaging and product factors and solutions
In addition to all environmental factors that may affect the weighing results, the weighing object itself can also affect the accuracy of the weighing process. Products that are prone to falling or moving on the conveyor are difficult to weigh. For the most accurate weighing results, all objects should pass the weighing sensor in the same position, ensuring that the number of measurements is the same and that the forces are distributed on the weighing sensor in the same way. As with the other issues discussed in this section, the main way to deal with these factors lies in the design and construction of the weighing equipment.
Before the products pass the load cell, they need to be guided to the appropriate position. This can be achieved by using guides, changing the conveyor speed, or using side clamps to control the product spacing. Product spacing is one of the most important factors in weighing. It may also be necessary to install sensors to ensure that the system does not start weighing until the entire product is on the load cell. This prevents incorrect weighing of unevenly packed products or large variations in weighing results. There are also software tools that can identify large deviations in weighing results and remove them when calculating the final result. Product handling and sorting not only ensure more accurate weighing results, but also further optimize the production process. After weighing, the system can sort the products by weight or better organize the products to prepare them for the next step in the production process. This factor has a great benefit to the overall productivity and efficiency of the entire production line.