American companies often employ aerospace-grade aluminum alloys, stainless steel joints, and advanced ball-and-socket mechanisms to allow smooth articulation. These skeletons enable silicone sex dolls to hold natural sitting, standing, and reclining poses, and in some premium models, they can mimic human-like resistance when moved. Engineers continuously test joint torque, range of motion, and weight distribution to ensure the TPE sex doll remains safe, balanced, and easy to position. The invention of frictionless or self-lubricating joints has further improved mobility and reduced wear over time, reflecting an ongoing pursuit of mechanical excellence.