Additive manufacturing (AM) process is an ideal way to rapidly prototype freeform optics. We present a new precision additive freeform optics manufacturing (AFOM) method using pulsed infrared laser to thermally cure optical silicones. To achieve the tight optical surface requirements, the curing volume pixel (voxel) of the AM process should be precisely controlled. We have developed an opto-thermal-chemical-coupled multiphysics model to simulate the curing process and predict the shape and size of cured polymer. Single-point curing experiments were conducted using a Q-switched fiber laser with an average power of 10 W and a repetition rate at 30 kHz. Numerical simulation shows a good agreement with the experiments, showing a path for a theoretically guided design of a high-precision AFOM process.