Ball-Joint Robot Effector for Precise Machining on Complex Surfaces
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current machining technologies, including manual drilling units, machine tools, and robots, face limitations in precision and flexibility when machining complex shapes due to rigidity issues and high investment costs, particularly in achieving large amplitude and precise trajectory control.
Innovation Solution
An effector assembly with an electro-spindle and a ball joint or stud-based foot system that allows for precise positioning and rigidity, enabling machining with three controlled axes and virtual rotation axes, allowing for complex shape machining without the need for a full five-axis CNC machine.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a robot arm is used to carry the cutting tool, then flexibility and ease of operation are improved, but machining precision and stability deteriorate due to flexibility of the robot arm
Solution Approach 1:
The system divides the machining system into two independent parts: the robot arm handles positioning and movement (flexibility), while the effector with ball joint handles precision machining (stability). This segmentation allows each component to optimize its function without compromising the other.
Solution Approach 2:
The effector acts as an intermediary between the robot arm and the cutting tool. It provides a rigid connection point through the ball joint that isolates the cutting tool from the flexibility of the robot arm, thereby maintaining machining precision while preserving robotic flexibility.
2Manufacturing precision
If a five-axis CNC machine tool is used, then machining precision and stability are improved, but device complexity and investment cost increase
Solution Approach 1:
The effector with ball joint provides five-axis machining capability (three from robot arm + two from ball joint rotations) using a simpler mechanical structure. This universal solution can perform complex machining operations without requiring a dedicated five-axis CNC machine tool, thereby reducing device complexity and investment cost.
Solution Approach 2:
The system changes the degrees of freedom parameters by adding two rotational degrees of freedom through the ball joint mechanism. This allows the simpler robot arm structure to achieve the functional equivalence of a complex five-axis CNC machine, reducing overall system complexity while maintaining machining precision.
3Device complexity
If the effector is directly coupled to the robot arm, then device complexity is reduced, but machining precision deteriorates due to lack of local rigidity
Solution Approach 1:
The ball joint mechanism uses spherical geometry to provide rigid rotational connections. The spherical interface between the ball and socket creates stable, precise rotational axes that maintain local rigidity at the cutting tool position, improving trajectory precision while keeping the overall effector structure relatively simple.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution enhances machining precision and productivity by providing local rigidity and maintaining contact without slipping, achieving quality comparable to traditional five-axis CNC machines at a lower investment cost, while allowing for the machining of complex shapes with improved stability and reduced risk of path deviations.
Implementation Method 1
the end-effector is connected to the surface to be machined by a ball joint when the foot of the effector is in contact
Data Source
Figure 1~2
Figure 3~5
AI summary
The present invention relates to a machining assembly comprising an effector intended to be mounted on a robot with multiple degrees of freedom, in which invention the mounting of the motor spindle relative to the intermediate supports and frame of the effector allows a numerically controlled movement along three axes X, Y, Z of a trihedron, the effector bearing on the piece to be machined or on the surrounding tools by means of a ball joint at the foot end of the effector. Since the effector bears on the piece to be machined or on the surrounding tools it is possible to create local stiffness and to obtain the precision required to guarantee the quality of the machining process.