Screw connection and its load capacity in components made by rapid prototyping technology

Abstract

The Department of Robotics at The Faculty of Mechanical Engineering has recently recognized the benefit of using components produced by rapid prototyping technology (RP) [1] over peripherals, in producing and servicing robotic devices. The percentage of the parts produced by rapid prototyping technology in some devices may exceed 80 percent. Employing this technology means, that connecting the various parts of the mechanical structure is done by bolting the joints. In doing so, the question of maximum fastening torque of such joints arose, giving consideration to the unknown mechanical material properties of the parts in the place of force action. This paper will deal with maximal torque and hence the force acting at the screw connection of the part made by RP technology. It also addresses the question of how the size of the area under the bolt head affects the load capacity of screw connection. Great emphasis is assigned to testing the bolt joint load capacity, relevant to the testing of the material samples. Additionally, the article provides specific measurement values, which may serve as a guideline for the design of joints using this concept. The article also builds on the knowledge gained from previous testing of the screw connections made by 3D print technology [2].