What are the reasons for the error of the silicone hose manufacturer’s silicone tube? There are subjective factors and objective factors for the error of silicone tubes. But it is mostly subjective factors. The temperature of the machine head, the melting point and fluidity of the extruded material.
Three factors such as different screw speeds and traction speeds
- Due to the influence of the head temperature.
Under the same extrusion conditions, if the temperature of the machine head is too low, the inner diameter of the extruded silicone sleeve becomes larger, and the wall thickness of the silicone hose becomes thinner; when the extrusion temperature is higher, the inner diameter of the silicone hose becomes smaller, then The wall thickness of the silicone hose becomes thicker.
- Due to the influence of the melting point and fluidity of the extruded material.
The fluidity of the material is closely related to the temperature. As the temperature increases, the apparent viscosity of the material decreases and the fluidity is good. When the temperature of the die is lowered, the apparent viscosity of the material is higher, and the fluidity is poor. Forced extrusion increases the pressure of the die. Stress is proportional.
At the same time, the poor fluidity of the material makes the material extrude less, resulting in a larger inner diameter of the silicone hose and a thinner wall thickness. As the temperature gradually increases, the flow performance of the extruded material in the machine head is improved, the pressure of the machine head is reduced, and the elastic recovery of the molded pipe is also reduced due to the stress, and the inner diameter of the extrusion is reduced; on the other hand , The amount of material extruded increases with the improvement of flow performance, which makes the wall of the silicone hose thicker.
- The influence of different screw speed and traction speed.
At the same temperature, the diameter and wall thickness of the extruded silicone sleeve have a great relationship with the screw speed and traction speed. As the extrusion speed increases, the inner diameter of the silicone sleeve will become larger and the tube wall will become thinner. , the lower the temperature of the machine head, the more obvious this change will be.
This is mainly because as the extrusion speed increases, although the viscosity of the material decreases with the increase of the shear stress (shear strength), due to the high processing pressure of the silicone melt, the viscosity also decreases with the increase of the extrusion pressure. improved.