Main factors affecting the tolerance of silicone tube
Oct 09, 2019
Any product has tolerances when it is produced, and the silicone tube production is the same. As a professional silicone manufacturer, the following briefly introduces some of the main factors affecting the tolerance of silicone tubes.
The first case: the effect of the temperature of the nose.
Under the same extrusion conditions, if the temperature of the 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 thickness of the silicone hose becomes thicker.
The second case: the melting point of the extruded material and the influence of fluidity.
The flow properties of the material are closely related to the temperature. As the temperature increases, the apparent viscosity of the material decreases and the flow performance is good. When the temperature of the machine head is lowered, the apparent viscosity of the material is high, and the flow performance is poor. The forced extrusion causes the pressure of the head to increase, and the blank of the die blank is elastically restored due to the release of the stress, and the degree of expansion is also the same as before. It is proportional to the pressure, and the poor fluidity of the material causes the material to be extruded less, resulting in a larger inner diameter of the silicone hose, and the wall thickness becomes thinner. With the gradual increase of temperature, the flow performance of the extruded material in the machine head is improved, the head pressure is reduced, and the release tube blank is also reduced due to the stress elastic recovery, and the extrusion inner diameter is reduced; The amount of material extrusion increases with the improvement of flow performance, which thickens the wall of the silicone hose.
The third case: the effect of different screw speed and traction speed.
At the same temperature, the tube 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, the wall of the tube will become thinner, and the lower the temperature of the 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 shear stress (shear strength), the viscosity of the silica melt is higher, and the viscosity is increased with the increase of extrusion pressure. It has also improved, and the flow properties of the material at this time depend to a large extent on the external heating temperature.
The above are the main factors affecting the tolerance of silicone tube. As a professional silicone tube manufacturer, our company strictly controls the production process to control the product tolerance within a reasonable range.