Polymethyl methacrylate (PMMA) resin is a high crystallinity thermoplastic engineering plastic. Due to its excellent mechanical properties and good molding processability, it is widely used in the field of mechanical components such as gears and bearing seats. The common grade M90-44 copolymer PMMA boasts excellent comprehensive properties. PMMA is a linear polymer without side chains, high density, and high crystallinity. Depending on the chemical structure of its molecular chain, it can be divided into homopolymer PMMA and copolymer PMMA. The key difference between them is that homopolymer PMMA has higher density, crystallinity, and melting point but poor thermal stability and a narrow processing temperature range (about 10℃), and slightly lower acid-base stability. In contrast, copolymer PMMA has lower density, crystallinity, melting point, and strength but good thermal stability, is not easily decomposed, has a wide processing temperature range (about 50℃), and better acid-base stability. As an engineering plastic with outstanding comprehensive properties, this material has a balanced mechanical, chemical, and thermal properties, along with superior molding processability, making it a top choice among today's engineering plastics.