Areal Surface Texture Parameter Measurement in Micro Injection Mould Cavities
Areal surface metrology in micro-cavities requires non-contact optical instruments with matched bandwidth filters to verify steel texture and polymer replication.
Ejection Force Reduction
Meaning
A decrease in the mechanical force required to push a solidified plastic part out of a mould cavity improves both the cycle time and the quality of the finished product. This Ejection Force Reduction is achieved by optimizing the mould design, modifying the polymer formulation, or adjusting the processing parameters. It prevents the part from being damaged or deformed by the action of the ejector pins.
Chemical Solution
Adding internal lubricants, such as erucamide or zinc stearate, reduces the friction between the polymer and the steel walls. These additives migrate to the surface of the part during cooling, forming a microscopic boundary layer that lowers the adhesive forces. This chemical approach is highly effective for polymers that shrink tightly onto the mould cores.
Processing Variable
Optimizing the cooling time, packing pressure, and melt temperature also contributes to lower ejection forces. If the cooling time is too short, the part remains soft and easily deforms under the pins, whereas excessive packing pressure over-compresses the polymer and increases the contact stress. The processor must balance these variables to maintain stable production.
Production Impact
Lower ejection forces decrease wear on the tooling and prevent costly down-time due to stuck parts.