Cold-working materials: various optical parts with a diameter or diagonal of 10~320mm and a length of ≤200mm, such as discs and squares; hot working materials: each with a diameter or diagonal of 350~1200mm and a thickness of ≤100mm Kinds of optical parts such as discs and squares; tolerance size: diameter tolerance: ±0.1mm, side length tolerance: ±0.1mm, thickness tolerance: ±0.1mm