# Suitability of UR5 Robot for Robotic 3D Printing
## 5 Assessing the Experiments Performed on the UR5 Robot  
After conducting tests and assessing the measured values, several conclusions were drawn regarding the suitability of the examined robot for robotic 3D printing. During the experiments with the UR5 robot, random vibrations occurred on rotational axis 5. The cause of these vibrations was not determined. However, it was possible that damage to the gearbox occurred during the experiments due to the robot's inability to handle self-collision states. The fault appeared to be random, as the vibrations would sometimes appear under the same measurement conditions and other times they would not. In order to ensure accuracy, more measurements than the standard 30 were needed to verify a single characteristic. This allowed for excluding samples while still having enough samples for assessment. As a result, the number of measurements needed doubled. This approach was necessary to ensure that the measurements performed could be declared relevant. It is therefore recommended that particular attention be paid to axis 5 when conducting mechanical analyses of the robot.  
While performing various measurements and positioning control tasks with the UR5 robot, we had several subjective experiences that may have introduced inaccuracies in its programming. The robot's path is determined by command points, which are specific points between which the robot can move in a straight line or along a circular path in either the articulated coordinate system or the tool coordinate system. Command points can be defined by manually moving the robot. However, rotating the tool (sixth axis) in this mode can be difficult by hand. Another method of defining the path is by moving the robot in joint coordinates, where the position of each joint is directly defined. In this data specification, reaching the desired point in the tool's coordinate system is challenging. The desired point can also be defined in the coordinate system of the tool; however, errors often occur when solving the inverse kinematics of the robot, resulting in robot errors. There is also confusion for the programmer regarding the methods of defining the direction of displacement and rotation in each axis. Additionally, path planning lacks tools for importing an object from a CAD file, for which tool motions could be created directly from the part model, even along more complex paths. The robot can also be switched to force mode, where the force to be applied to the robot by the tool is entered instead of entering a position in a given direction (maximum 150 N). The robot has a significant issue with self-collision at its joints. The robot's programming does not account for self-collision situations, and the motion simulation does not detect self-collision. During tests, the robot did not reach the maximum joint speed of 180\({}^{\circ}\)/s as specified by the manufacturer; instead, it only achieved a maximum positioning speed of 120\({}^{\circ}\)/s. In linear mode, where inverse kinematics is required, the robot should reach its maximum speed. Other industrial robots of similar size have significantly higher repetitive positioning accuracy. The measurements only detected accuracy in the static state, so it would be beneficial to focus on verifying the robot's accuracy during motion in further research.