Texturing injection molds using microelectronics techniques

In recent years, there has been growing interest in imparting specific properties to the surfaces of polymers. This functionalization can be achieved through microinjection molding. For the first time, this study introduces the use of {Cl 2 /Ar} plasma etching on an injection mold made of X38CrMoV5. However, scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX) analyses revealed the presence of nonvolatile chlorine residues on the mold surface, which were oxidized upon exiting the reactor. Therefore, {H 2 }, {N 2 }, and {O 2 } plasma post-treatments were performed to reduce chlorine formation. Among these, the {H 2 } post-treatment was the most effective, delaying the onset of corrosion by 90 days. To further enhance this protection, a Cr/CrN bilayer was deposited on the mold surface. However, this coating was required to meet specific criteria to ensure its durability and accurate replication of the molded parts. Characterization analysis revealed that the coating uniformly covered the mold textures, demonstrated good mechanical properties, adhered well to the mold, and showed no degradation after 1000 injection cycles. Furthermore, injection tests demonstrated excellent replication of micrometric patterns on polypropylene (PP) parts. • A {Cl 2 /Ar} plasma etching protocol for texturing injection molds made of X38CrMoV5 steel was established. • Corrosion resistance was prolonged through a {H2} post-treatment. • Corrosion resistance was reinforced with the deposition of a Cr/CrN bilayer. • The coating demonstrated excellent thickness uniformity, strong adhesion to the mold, and good mechanical properties. • This established texturing method enables rapid and large-scale production of plastic parts that can be functionalized.