Variations in the atomic and molecular composition of plastics
Posted: Wed Feb 12, 2025 9:32 am
For example, in the molding process of thermosetting plastics, the structure of the molecules that make up the resin is transformed from linear to three-dimensional. Since the bulk density of the three-dimensional structure is greater than that of the linear structure, and since the total volume of the linear structure is reduced, the three-dimensional structure becomes smaller.
· Change in residual stress
The molding pressure force, anisotropy, uneven mixing of additives and mold temperature can affect the tool during its use in the production of plastic injection molding products.
After molding, there is still some residual iran number data stress in the mold. This residual stress will gradually decrease and redistribute over time. As a direct consequence, the mold will shrink again. This type of shrinkage is sometimes called post-shrinkage.
· Sprue cross-section size
There is a wide range of cross-sectional sizes for injection molds. Larger runners increase cavity pressure and increase gate closing time, allowing more molten material to enter the cavity. This is achieved by increasing melt flow.
· A type of plastic
Crystalline polymers such as polypropylene (PP) and polyamide (PA) have greater shrinkage after demolding and a wider shrinkage range than non-crystalline plastics such as polycarbonate (PS) and acrylonitrile butadiene styrene (ABS).
· Change in residual stress
The molding pressure force, anisotropy, uneven mixing of additives and mold temperature can affect the tool during its use in the production of plastic injection molding products.
After molding, there is still some residual iran number data stress in the mold. This residual stress will gradually decrease and redistribute over time. As a direct consequence, the mold will shrink again. This type of shrinkage is sometimes called post-shrinkage.
· Sprue cross-section size
There is a wide range of cross-sectional sizes for injection molds. Larger runners increase cavity pressure and increase gate closing time, allowing more molten material to enter the cavity. This is achieved by increasing melt flow.
· A type of plastic
Crystalline polymers such as polypropylene (PP) and polyamide (PA) have greater shrinkage after demolding and a wider shrinkage range than non-crystalline plastics such as polycarbonate (PS) and acrylonitrile butadiene styrene (ABS).