During the process of injection molding, due to the poor exhausting condition of molds, the water vapor in the melt, the air in cavity, the volatile gas from volatile substance in raw materials as well as the material decomposition gas either remain inside the products to form air bubble […]
As for molding technics. Air bubble or air cavitation may occur in the plastic parts due to improperly-controlled material temperature and mold temperature, overfast injection speed, overlow injection pressure, too large or too small quantity of injection, insufficient dwell, unbalanced or insufficient cooling etc. […]
As for product structure and mold design. Optimize mold exhausting scheme, and exhausting channel should be particularly set at confluence of front materials of plastic melt in the cavity; […]
Crazing is silvery white filamentous speckle occurring on the surface or near-surface of injection products along the direction of melt flow. It is resulted from the moving of gas in the resin which is then stored in between the melt and surface wall of cavity and subsequently crushed. […]
Flow marks refer to the obvious flow cracks of melt that can be found near the gate. […]
It is a snake-shaped squirt flow formed upon the melt’s entering the cavity with thick walls and large section with excessively high injection rate. […]
When melt with unsteady flow is injected into the mold cavity through the runner and gate in semi-solidified state, […]
When the melt flows from a runner with narrow section into a cavity with large section or when the runner is very narrow and the surface roughness is rather poor, turbulence flow will form within the runner (including the cavity), thereby resulting in the turbulence flow mark on the surface of plastic parts. [...]
The volatile gas produced from the resin in the melt and the lubricating agent under processing temperature is stored in between the melt flow and surface wall of cavity and interferes the flow of melt, […]
Both the shrink mark and shrinkage porosity are defects of injection products due to the molding shrinkage at thick walls where no sufficient follow-up compensation is made. During the injection molding process, the surface layer of products often condenses first, followed by the center layer, which will cause sinking on the surface of parts with [...]