Filling accuracy of capsule filling machine

Filling accuracy of capsule filling machine

At present, most of the domestic capsule filling machines are standard models of quantitative filling. The filling volume is determined by the thickness of the measuring plate and depends on the free density of the filling material. At the same time, the accuracy of filling quantity control is related to the influencing factors of filling structure and filling material itself.

The hygroscopicity of the filling material is a factor affecting the control accuracy. When the filling powder or particle viscosity is too high and the fluidity is poor, the viscosity will produce plug powder. Usually, during the process of the mixed filling of any drug powder or particle, the humidity will be controlled below 3%. In addition, the moisture absorption capacity of the filler is related to its critical relative humidity. Generally speaking, when the purity of filling powder or particle is not high, its critical relative humidity decreases and multi-component increases the hygroscopicity. Both will make the filling process thicker, thus increasing the volume of the load and making it easier for the plug powder to occur. Excessive water absorption can also render a drug ineffective. Therefore, in the process of filling, the environmental humidity should be controlled under its critical relative humidity. The corresponding relative humidity varies with the change of drugs. However, the capsule body also has certain humidity requirements. Due to the low humidity of the capsule body, it is easy to rupture, so the overall humidity of the filling environment of the capsule body is controlled within 40-60%.

There are two main filling methods for the capsule filling machine, one is the piston filling of the drug feeder, and the other is the metering plate filling. Different filling methods have different prescription requirements. Piston packing requires good fluidity of the powder to ensure the full injection of the powder column. In addition, the powder must have good pretension to ensure that the powder tower is not easily broken.

The filling of the gauge plate also requires sufficient lubricant to facilitate the compression of the powder column, thereby avoiding the film cover and reducing friction between the sliding parts. At the same time, the powder must have the stamping ability, in order to press the powder column into good shape, but this stamping ability is not as strict as the plunger packaging requirements. Good powder fluidity is required for the filling of the metering tray, which is also reflected in the powder used to ensure the uniform distribution of the dosing tray, thus ensuring the uniformity of the filling.