3Flex - 3D Printable Parametric Tendon-driven Manipulator

What is it?The 3Flex (Fused Filament Fabrication Flexible Instrument) is a parametric, 2DOF, tendon-driven manipulator design, that is 3D printable on most¹ home FFF printers.The idea was born as an idea for a steerable catheter design during Fabian Trauzettel's PhD project in the BITE group at TU Delft.This work was supported by the ATLAS project. This project has received funding from the European Union’s Horizon 2020 research and innovation program under the Marie Skłodowska-Curie grant agreement No 813782.The project website can be found here.¹A 0.25mm Nozzle is recommended. Printing with a 0.4mm nozzle is possible, but requires some modification of the CAD model. What does it do?3Flex provides an easy to manufacture, affordable platform to build and test small-scale tendon-driven manipulators. Multiple 3Flex segments, each capable of bending in 2DOF, can be arrayed serially to create highly dextrous effectors. The design can be easily tailored to the requirements of the specific application by changing the parameters of the OpenSCAD file. This lets you modify not only broad dimensions like diameter, lumen sizes, length or maximum bending angle of each segment, but also vary more subtle parameters like the thickness of the segment helix or spine, thereby changing the stiffness of the segment. All of this is implemented taking into account the math used by Slic3r and its derivatives to make sure that the thin sections are not too thin to print, and thicker areas are composed of nice, parallel extrusion lines with no infill or gaps. Instructions for use:Download 3Flex.scad and PrusaSlicerConfig.ini.Download and install OpenSCAD and PrusaSlicerOpen 3Flex.scad in OpenSCAD and use the customizer on the right side of the screen to select your preferred segment configuration and printer settingsRender the final design (this may take some time) by pressing F6 or pressing the render icon on the editor ribbon.Export the resulting .stl file to a convenient locationOpen PrusaSlicer and go through the setup wizard for your specific 3D printer. Manual configuration for unsupported machines is also possible. Go to File>Import>Import Config (or press Ctrl+L) and import PrusaSlicerConfig.iniImport the .stl File from step 5 into PrusaSlicerOrient the part to lie on its flat side by clicking it in the plater window and using the "place on face tool" (or press F) and selecting the now-highlighted flat side of the shaft.Under print settings, select "new_FDMflex_0.15mm QUALITY @0.25 nozzle MK3", as well as your filament and printer settings.Click "Slice now" to generate the G-code for your printerHappy printing!Some tips:Use a craft knife or box cutter to gently separate the raft from the part, and then run the blade through the helix to remove any stringing or blobs. If you are assembling multiple segments, it is wise to alternate right and left hand helices (set "Helix handedness" to 1 or -1 in the OpenSCAD customizer) to prevent twisting of the resulting shaftTendons can be any material that is readily available, but the material should be flexible and not elongate too much under load to keep the manipulator's behaviour predictable; Spectra and Dyneema are good options and are available in a range of diameters and breaking strengths as fishing line.Tendons are threaded into the shaft from base to tip, knotted around the shaft groove at the tip, and then threaded back down the shaft on the opposite side of the shaft. This way, one piece of thread makes two steering tendons. An example image is located here.一、产品概述 3Flex（熔融丝材制造柔性操作器，Fused Filament Fabrication Flexible Instrument）是一款参数化、2自由度（2DOF）绳驱操作器（tendon-driven manipulator）设计方案，可在绝大多数家用熔融丝材制造（Fused Filament Fabrication，简称FFF）3D打印机上完成打印。 该设计起源于代尔夫特理工大学BITE课题组Fabian Trauzettel博士阶段的可导向导管设计构思。本研究得到ATLAS项目资助，本项目获欧盟地平线2020研究与创新框架下玛丽·居里研究员资助协议（编号813782）支持。项目官网可参见此处。 ¹ 推荐使用0.25mm口径喷嘴。虽可使用0.4mm喷嘴进行打印，但需对计算机辅助设计（CAD）模型进行适当修改。 二、功能特性 3Flex提供了一款易于制造、成本低廉的开发平台，用于搭建与测试小型绳驱操作器。多个3Flex单元（每个单元均可实现2自由度弯曲）可串联排布，构建出高灵活性的执行末端。可通过修改OpenSCAD文件中的参数，快速适配特定应用场景的需求：不仅可修改各单元的直径、内腔尺寸、长度、最大弯曲角度等宏观尺寸参数，还可调整单元螺旋结构或支撑结构的厚度等精细参数，进而改变单元的刚度。所有参数调整均兼容Slic3r及其衍生切片软件的计算逻辑，确保薄壁区域厚度满足打印要求，厚壁区域可生成均匀平行的挤出线条，无填充不足或间隙问题。 三、使用指南 1. 下载3Flex.scad与PrusaSlicerConfig.ini文件。 2. 下载并安装OpenSCAD与PrusaSlicer软件。 3. 在OpenSCAD中打开3Flex.scad，通过界面右侧的自定义面板选择所需的单元配置与打印机参数。 4. 按下F6键或点击编辑器工具栏的渲染图标，生成最终设计模型（此过程可能耗时较长）。 5. 将生成的.stl格式文件导出至指定路径。 6. 打开PrusaSlicer，按照向导完成对应3D打印机的配置；若设备未被内置支持，也可手动进行配置。 7. 依次点击「文件>导入>导入配置」（或按下快捷键Ctrl+L），导入PrusaSlicerConfig.ini配置文件。 8. 将步骤5中导出的.stl文件导入PrusaSlicer。 9. 在打印平台窗口中选中模型，使用「放置平面工具」（或按下快捷键F），选择轴体当前高亮的平坦侧面，将模型摆正至平坦侧面贴合打印平台。 10. 在打印设置中选择「new_FDMflex_0.15mm QUALITY @0.25 nozzle MK3」配置，并设置耗材与打印机参数。 11. 点击「立即切片」，生成适配您打印机的G代码。 祝您打印顺利！ 四、使用小贴士 1. 使用工艺刀或美工刀轻轻分离打印基底（raft）与模型，随后沿螺旋结构滑动刀片以去除拉丝现象（stringing）与溢料（blobs）。 2. 若需组装多个单元，建议交替使用左旋与右旋螺旋结构（在OpenSCAD自定义面板中将「Helix handedness」设为1或-1），以避免轴体发生扭转。 3. 驱动绳可选用任意易得的柔性材料，但需确保材料在负载下伸长量较小，以保证操作器的运动特性可预测；光谱纤维（Spectra）与迪尼玛（Dyneema）为优质选择，二者均有多种直径与断裂强度规格的渔线版本可供选购。 4. 驱动绳从轴体基座穿入至顶端，在顶端绕轴体凹槽打结后，从轴体另一侧的凹槽穿回基座。如此一来，单根线材即可兼作两根操控绳。示例图片可参见此处。