Packaging machinery, an important step is to weigh the material. Materials are divided into powdered materials, viscous materials, two kinds of materials weighing design stepper motor application mode is different, the following categories of materials to explain the application of stepper motor respectively.
Powdered material metering
Screw metering is a common volumetric measurement method, it is through the number of rotating turns of the screw to achieve the amount of measurement, in order to achieve the measurement of the size of adjustable and improve the accuracy of the purpose of the measurement, the requirements of the screw speed can be adjusted and positioned accurately, the use of stepper motors can meet the requirements of both aspects.
For example, the powder packaging machine metering using a stepper motor to control the speed and rotation of the screw, not only simplifies the mechanical structure, but also makes it very easy to control. In the case of no load, the speed of the stepper motor, the position of the stop only depends on the frequency of the pulse signal and the number of pulses, and is not affected by changes in load, which has obvious accuracy advantages compared with the electromagnetic clutch control of the screw metering, more suitable for the measurement of materials with relatively large changes in specific gravity.
Stepper motor and screw using a direct connection, the structure is simple and convenient. It is worth pointing out that, as the stepper motor overload capacity is more generation, when slightly overloaded, there will be considerable noise. Therefore, after the metering working condition is determined, a larger overload coefficient should be selected to ensure that the stepper motor works in balance.
Metering of viscous materials
Stepper motor control gear pump can also achieve accurate metering. Gear pumps are widely used in conveying viscous materials, such as syrup, bean paste, white wine, oil, ketchup and so on. At present, in the metering of these materials mostly use piston pumps, there are difficult to adjust, complex structure, inconvenience, high power consumption, inaccurate measurement and other shortcomings.
Gear pump metering is measured by a pair of gears meshing and rotating, the material is forced from the inlet to the outlet through the space of teeth and teeth. The power comes from the stepper motor, the position and speed of the stepper motor rotation is controlled by the programmable controller, the metering accuracy is higher than the metering accuracy of the piston pump.
Stepper motor is suitable for operation at low speed, when the speed is accelerated, the noise of the stepper motor will be significantly increased, and other economic indicators will be significantly reduced. For higher speed gear pumps, the choice of speed structure is better. In the viscous packaging machine began to use the structure of the stepper motor direct gear pump, the noise is difficult to avoid, the reliability is reduced. Later, the use of spur gear speed approach to reduce the speed of the stepper motor, the noise is controlled, reliability has also improved, metering accuracy is guaranteed.
Post time: Jul-04-2023