Across multiple articles, engineers use advanced CAD to create high-precision 3D models of lens barrels, lens holders, and aperture blades to meet strict optical-tolerance requirements for coaxiality, runout, and mating clearance. They translate imaging-system needs—aberration control, stray light suppression, and temperature adaptability—into design features such as optimized anti-reflection thread layouts, stress-relief grooves, and multi-material matching structures. The assembly process emphasizes centering and stress control, optimizing stiffness distribution and retaining-ring thread parameters to minimize interference and preserve optical performance. Dynamic simulations of moving components and thermal matching studies ensure imaging stability across temperature ranges by selecting materials with closely matched thermal expansion coefficients. A specialized material system is proposed, pairing Invar or Super Invar for lens barrels and holders with non-magnetic stainless steel for focusing shafts and high-elasticity beryllium for aperture blades, to support ultra-precision machining of high-performance optical instruments.