A method of forming channels within a substrate includes: (a) molding a sacrificial component directly into the substrate; (b) igniting the sacrificial component to cause a deflagration of the sacrificial component, thereby forming a channel in the substrate; and (c) cleaning the channel in the substrate to remove byproducts of the deflagration of the sacrificial component. The sacrificial component includes a combustible material with a protective shell, and the substrate includes a polymeric material.

A method of forming channels within a substrate includes: (a) molding a sacrificial component directly into the substrate; (b) igniting the sacrificial component to cause a deflagration of the sacrificial component, thereby forming a channel in the substrate; and (c) cleaning the channel in the substrate to remove byproducts of the deflagration of the sacrificial component. The sacrificial component includes a combustible material with a protective shell, and the substrate includes a polymeric material.