# Suitability of UR5 Robot for Robotic 3D Printing
## 3 Measuring Crucial Robot Performance Characteristics
### Robot Static Compliance  
Static compliance is an important factor that affects robot accuracy and performance. In robotics, static compliance is defined as the degree of deformation of a robotic structure under the influence of a static load. In other words, it measures how much a robot \"sags\" or deforms when a force is applied to it without motion. High static compliance can lead to the following problems:  
* Inaccurate positioning--The robot deforms under pressure, and the end effector may not be exactly in the programmed position, which can result in errors in object handling or task execution.
* Vibration--Deformation of the robotic structure can produce vibrations that affect the accuracy of sensors and control systems, reducing the overall stability of the robot.
* Reduced load capacity--High static compliance can decrease the maximum load capacity of the robot, as the structure may not be able to cope with high forces without undesired deformation.  
To achieve optimal robot performance in various applications, measuring and reducing static compliance is crucial. There are several methods for measuring a robot's static compliance. The first method involves applying a static force to the robot's end effector and then measuring the resulting deformation of the structure in that direction. The second method uses force sensors integrated into the robot structure to measure force and deformation in real time. Additionally, the robot's static compliance rate can be determined through finite element modeling (FEM) by applying different loads at defined locations in the structure using CAE tools to determine the deformation of the structure.  
In order to reduce static compliance in the manufacture of robotic devices, manufacturers primarily focus on selecting the appropriate materials for the robot's structure. They also optimize the design by incorporating various stiffening elements in the structure and ensure the continuous advancement of active control systems to compensate for the deformation of the robotic structure in real time.  
In robotic 3D printing, a robot's static compliance is a crucial factor affecting prints' accuracy and quality. It is important to measure and reduce static compliance in 3D printing by optimizing printing speed, selecting the appropriate print path, and configuring a fast feed. This is essential for achieving optimal quality results for the products produced. Elevated static compliance can lead to a range of issues, including  
Figure 1: Common process errors in robotic 3D printing; (**a**) warping, (**b**) layer shifting, (**c**) vibration and ringing, (**d**) stringing.  
* Inaccurate positioning of the nozzle due to the pressure applied by the print head during the application of the material layer. For this reason, the nozzle may not be in the exact intended position. This can lead to uneven filament deposition and errors in the dimensions of the prints.
* Deformation of the robot structure can produce vibrations that affect the nozzle's motion and the printed line's quality. Vibrations manifest themselves as waves and unevenness on the surface of the prints.
* High static compliance can reduce the robot's maximum load capacity, limiting its capability to handle heavier objects and push at higher speeds.