Processing, thermoplastics contact force

Melted thermoplastics have special characteristics, particularly because pushing force creates what is generally described as Poiseuille Flow in the material. When pushed, the molding material exhibits different levels of shear stress across the thickness of the part. Variations in stress levels can be controlled through design and processing, but are always a consideration in thermoplastic injection processes. Stress variations can affect the physical strength of the part, influence its ability to maintain shape and dictate its reaction when contacted by solvents or other chemicals. 

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