ISO 25178 Surface Parameters for Injection Moulding Optical Components
ISO 25178 areal parameters define 3D optical surface texture to control stray light and guide injection moulding process windows for precision lenses.
Tool Temperature Cooling Cycle
Meaning
A thermal control phase in injection molding determines the rate of polymer solidification within the cavity. The tool temperature cooling cycle constitutes the largest portion of the total molding cycle time, directly influencing the productivity and economics of the process. In polymer sourcing and molding, this phase determines the final crystalline structure, shrinkage, and warpage of the molded component.
Thermal Management
Regulation of the mold temperature requires a continuous flow of heat transfer fluid through cooling channels designed within the tool. During the tool temperature cooling cycle, heat is extracted from the molten polymer until the part reaches its ejection temperature. The rate of heat extraction must be uniform across the part to prevent differential shrinkage and residual stresses.
Warpage Control
Non-uniform cooling causes differential shrinkage, which leads to part warpage and dimensional instability. The tool temperature cooling cycle must be long enough to allow the polymer to solidify completely, ensuring the part can withstand ejection forces without deforming. If the cycle is too short, the center of the part remains soft and prone to post-molding distortion.
This defect is particularly common when using semi-crystalline resins, which require controlled cooling to develop the necessary crystal structure and mechanical properties.
Cycle Optimization
Reducing the cooling time without sacrificing part quality is a primary goal for high-volume molding. Optimizing the tool temperature cooling cycle involves a balance between mold temperature, cooling channel layout, and polymer properties. High-conductivity mold inserts can be used to accelerate heat transfer and shorten the cycle time.