https://www.avient.com/sites/default/files/2020-10/tpe-overmold-design-guide.pdf
If vents are not incorporated into the mold design, the adhesion of the TPE to the substrate can be critically affected in specific areas of the part where air is trapped in the cavity during injection.
As the TPE melt is injected into the mold cavity, the air in the cavity must be able to effectively exit the tool.
As the TPE melt is injected into the mold cavity, the air in the cavity must be able to effectively exit the tool.