Selecting the right thermoplastic for a custom injection‑molded part is rarely a straightforward decision. Three materials dominate the conversation—Polypropylene (PP), Acrylonitrile Butadiene Styrene (ABS), and Polycarbonate (PC). Each offers a distinct balance of mechanical properties, processability, and cost.This guide cuts through the marketing noise and delivers a side‑by‑side technical comparison to help engineers, procurement managers, and product designers make a confident, application‑driven choice.