Double-sided lapping process is a key technology for obtaining high efficiency and flatness in fabricating plane-parallel workpiece surfaces, such as wafers, optical windows, seal rings, etc. However, the formation of the concave and convex surface shapes of workpieces was rarely investigated in the previous research, and the mechanism was unknown. This paper establishes a new kinematic model to clarify the formation mechanism of concave and convex surface shapes, in which the workpiece eccentricity and rotation in the planetary wheel are considered for the first time. The measurement and control method of workpiece rotational speed in the planetary wheel is proposed. The formation of the concave and convex surface shapes is validated experimentally by adjusting the rotational speed of the workpiece, and the results show a good consistency with the calculation results. A flatness error convergency method is proposed based on the surface shape formation mechanism, and flatness superior to 5 µm is achieved on Φ200 × 2 mm thin copper substrates.

双面研磨工艺是获得高效率和平坦度的关键技术，用于制造平面平行的工件表面，如晶片、光学窗口、密封环等。然而，工件表面凹凸形状的形成却很少。前人研究过，机制不明。本文建立了一种新的运动学模型，阐明了凹凸表面形状的形成机制，其中首次考虑了行星轮中工件的偏心和自转。提出了行星轮内工件转速的测量与控制方法。通过调整工件的旋转速度，实验验证了凹凸表面形状的形成，结果与计算结果具有良好的一致性。提出了一种基于表面形状形成机理的平面度误差收敛方法，在Φ200×2 mm的薄铜基板上实现了优于5 µm的平面度。