How to consider the flow characteristics of materials when designing a transfor mold?
Publish Time: 2024-11-05
When designing a transfor mold, it is crucial to fully consider the flow characteristics of materials to ensure mold performance and molded part quality.
First, it is necessary to understand the types of materials and basic flow properties. Different materials, such as metals and plastics, have very different flow characteristics. For metal materials, aluminum alloys have good fluidity, while titanium alloys are relatively poor. When designing mold channels and cavities, for aluminum alloys with good fluidity, more complex flow channels can be appropriately designed to achieve a more sophisticated part structure; for titanium alloys, the flow channels should be as simple and smooth as possible, avoiding sharp corners to prevent material flow obstruction.
Secondly, analyze the flow behavior of the material under pressure. During the deformation process, the material is subjected to pressure of different directions and magnitudes in the mold. For example, in an injection mold, the plastic melt enters the cavity under injection pressure. When designing, the cross-sectional area of the flow channel should change gradually, with a larger area at the melt inlet and gradually shrinking as it approaches the cavity to ensure a reasonable distribution of pressure, promote uniform and stable flow of the material, and avoid vortices or stagnation caused by sudden changes in pressure. These poor flows will cause internal defects of the parts, such as bubbles and cracks.
In addition, consider the effect of material temperature on flow. Generally speaking, the fluidity of the material increases with increasing temperature. In mold design, for molds of thermoforming processes, heating or cooling channels should be reasonably designed. For example, in die-casting molds, appropriately increasing the local temperature of the mold can improve the filling effect of the metal liquid in complex parts and ensure the integrity of the parts. However, attention should also be paid to controlling the temperature gradient to prevent the material flow direction from deviating from the expected direction due to uneven temperature, affecting the dimensional accuracy and quality of the parts.
In addition, the viscosity of the material is also a key factor. High-viscosity materials require greater pressure to drive their flow. When designing molds, for molding molds of high-viscosity materials, the flow channel diameter should be appropriately increased and the flow channel length should be shortened to reduce the resistance to material flow so that the material can smoothly fill the entire mold cavity, thereby producing parts that meet the design requirements.
