Analysis of the Reasons for the Sagging of IBC Ton Barrel Billet and How to Solve the Leakage of IBC Ton Barrel

The sagging of IBC ton barrel billets can cause significant changes in wall thickness and diameter, and even damage the billets. For Newtonian fluids, sagging can be controlled by using high viscosity materials. However, in reality, most plastics are not Newtonian fluids, and their melt index is less than 1, which can cause sagging. As the temperature increases, the sagging will become more severe. Due to the viscoelasticity of plastic melt, it is not possible to describe the relationship between sag and melt viscosity.

Some people believe that the sagging of IBC ton barrel billets is determined by the viscoelasticity of the melt, while linear creep compliance estimates that sagging is calculated by the relaxation coefficient. Other viewpoints suggest that the growth function of tensile stress is related to sagging. J. from the university D. It is pointed out that the process of sagging is neither a process of constant stress nor a process of constant strain rate, so these processes are not directly related to sagging in physics. It should be noted that when the strain rate is very small, a simple model of viscoelastic fluid can be used to predict sag.

At present, there is no reliable method for predicting sagging behavior based on rheological properties. Therefore, empirical methods can only be used to predict the downward trend. One method is to use a mold to clamp the extruded material with a fixed length and weight, and then monitor and record the variation of the blank length over time. This simple method is very useful for measuring the ductility of thin film plastics.

When considering the effects of export expansion and sagging comprehensively, from a rheological perspective, it becomes more complex. After the extrusion stops, the length of the IBC ton barrel billet depends on the expansion and sagging of the outlet. In practical situations, such as curve 3, the length of the steel billet slowly increases and the rebound is slow, which reflects the complex process of part outlet expansion over time.