3D-printing allows for fluid-controlled linear actuators with unconventional shapes

Heliyon, vol. 10, pp. e26497

Abstract

Background: Pneumatic actuators are widely used in applications like (medical) robots, or prostheses. Pneumatic actuators require a complex manufacturing process and are produced in standardized dimensions to reduce costs. Over the last decade 3D-printing has emerged as a cost-effective and efficient production method in medical applications. 3D-printing can also function as a cost-efficient alternative production method for pneumatic actuators. Objective: The goal of this research is to study the possibility of creating a pneumatic linear actuator with 3D-printing. Furthermore, the aim is to use the advantage of 3D-printing to create pneumatic actuators with non-circular cross-sections. Methodology: To evaluate the performance of a 3D-printed pneumatic actuator, a test setup was designed and built to measure the leakage and sliding friction force. Furthermore, two pneumatic actuators with a non-conventional cross-sectional shape were designed and their performance was tested and compared with a 3D-printed cylindrical pneumatic actuator, since these tests only ran once, the results are more a guideline. During the manufacturing of the cylinders, no post-processing techniques were used. Results: The functioning of a 3D-printed circular pneumatic actuator was proven with low static leakage rates of 2.5%, low dynamic leakage rates of approximately 1%, and a maximum friction force of Image 1. Furthermore, the results show that it is possible to print functioning pneumatic cylinders with a non-cylindrical concave cross-section. The non-conventional cylinders were tested up to Image 2 with maximum dynamic leakage of Image 3. Conclusion: This study demonstrates a method to create functional pneumatic linear actuators with 3D-printing. It was possible to create 3D-printed actuators with a conventional shape, e.g. circular and unconventional shapes e.g. stadium/oval shape and a kidney shape. The leak rates for conventional and unconventional shapes were in the same range. This opens up the world for more design freedom in pneumatic actuators.

Authors 4

1. Eva Zillen

   Delft University of Technology

   Affiliation as printed

   Delft University of Technology, Department of Biomechanical Engineering, Faculty of Mechanical Engineering, the Netherlands

2. Bob van der Windt corresponding

   Delft University of Technology

   Affiliation as printed

   Delft University of Technology, Department of Biomechanical Engineering, Faculty of Mechanical Engineering, the Netherlands

3. Heike Vallery corresponding Aachen Department of Automated Control Faculty of Mechanical Engineering

   RWTH Aachen University · Delft University of Technology

   Affiliation as printed

   Delft University of Technology, Department of Biomechanical Engineering, Faculty of Mechanical Engineering, the Netherlands

   RWTH Aachen, Department of Automated Control, Faculty of Mechanical Engineering, Germany

4. Gerwin Smit corresponding

   Delft University of Technology

   Affiliation as printed

   Delft University of Technology, Department of Biomechanical Engineering, Faculty of Mechanical Engineering, the Netherlands