Additive manufacturing by layerwise photopolymerization, commonly called stereolithography (SLA), is attractive due to its high resolution and diversity of materials chemistry. However, traditional SLA methods are restricted to planar substrates and planar layers that are perpendicular to a single-axis build direction. Here, we present a robotic system that is capable of maskless layerwise photopolymerization on curved surfaces, enabling production of large-area conformal patterns and the construction of conformal freeform objects. The system comprises an industrial six-axis robot and a custom-built maskless projector end effector. Use of the system involves creating a mesh representation of the freeform substrate, generation of a triangulated toolpath with curved layers that represents the target object to be printed, precision mounting of the substrate in the robot workspace, and robotic photopatterning of the target object by coordinated motion of the robot and substrate. We demonstrate printing of conformal photopatterns on spheres of various sizes, and construction of miniature three-dimensional objects on spheres without requiring support features. Improvement of the motion accuracy and development of freeform toolpaths would enable construction of polymer objects that surpass the size and support structure constraints imparted by traditional SLA systems.

中文翻译：

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保形机器人立体光刻。

通过分层光聚合进行的增材制造（通常称为立体平版印刷术（SLA））因其高分辨率和材料化学多样性而具有吸引力。但是，传统的SLA方法仅限于垂直于单轴构建方向的平面基板和平面层。在这里，我们介绍了一种机器人系统，该系统能够在曲面上进行无掩模分层光聚合，从而能够生产大面积的共形图案并构建无形的共形物体。该系统包括一个工业六轴机器人和一个定制的无掩模投影机末端执行器。该系统的使用涉及创建自由形式基材的网格表示，生成带有弯曲层的三角工具路径，该曲线层表示要打印的目标对象，精确地将基板安装在机器人工作空间中，并通过机器人和基板的协调运动对目标对象进行机器人光图案化。我们演示了在各种尺寸的球体上保形光图案的印刷，以及在不需要支撑功能的情况下在球体上构建微型三维物体的过程。改善运动精度和开发自由形式的刀具路径将使聚合物对象的构造超过传统SLA系统赋予的尺寸和支撑结构约束。并在不需要支撑特征的情况下在球上构造微型三维物体。运动精度的提高和自由形式刀具路径的发展将使聚合物对象的构造超过传统SLA系统赋予的尺寸和支撑结构约束。并在不需要支撑功能的情况下在球上构造微型三维物体。改善运动精度和开发自由形式的刀具路径将使聚合物对象的构造超过传统SLA系统赋予的尺寸和支撑结构约束。