Parallel Robot Spindle Machining for Large Part Undersides
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Solution Overview
Problem
Conventional milling processes using CNC machining centers are limited in size, inefficient for complex surfaces, costly, and inflexible, while six-axis industrial robots suffer from low stiffness affecting accuracy.
Innovation Solution
A parallel robot assembly with a servo spindle and machining tool, mounted on a platform under the mechanical part, allows for translation along multiple axes and tool rotation, enabling efficient and flexible machining from the bottom side with improved accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a CNC milling machine or machining center is used to process mechanical parts, then high-accuracy machining can be achieved, but it is limited to small to medium size parts and cannot process large size parts
Solution Approach 1:
Instead of moving the workpiece under a fixed spindle (traditional CNC approach), the patent inverts the system by placing the spindle on a mobile robot arm that moves to the workpiece. This allows the machining system to adapt to parts of various sizes, from small to large, while maintaining machining accuracy through the robot's positioning capabilities
Solution Approach 2:
The mobile robot-based machining system can process mechanical parts of different sizes and types using the same equipment, eliminating the need for dedicated machining centers for different part sizes. The system provides universal machining capability across a wide size range
2Adaptability or versatility
If a five-axis machining center is adopted to process mechanical parts with complex curved surfaces, then processing capability is improved, but processing efficiency decreases
Solution Approach 1:
The mobile robot arm provides dynamic positioning and movement capabilities, allowing the spindle to reach complex surfaces efficiently. The robot's flexible kinematics enable it to adapt to complex curved surfaces while maintaining high-speed movement, thus improving both processing capability and efficiency
3Adaptability or versatility
If a large scale machining center or gantry type machining center is used to support processing of larger size parts, then processing capability is improved, but cost increases
Solution Approach 1:
Instead of investing in expensive large-scale machining centers, the patent uses a more cost-effective mobile robot-based system. The robot arm, while less expensive than a gantry machining center, provides sufficient positioning accuracy and can be repositioned or replaced more easily, reducing overall system cost
4Manufacturing precision
If a machining center is used, then dedicated and customized fixture tooling is needed to process different mechanical parts, but flexibility decreases
Solution Approach 1:
The mobile robot system provides dynamic repositioning and programmable movement, allowing the same equipment to process different parts without dedicated fixtures. The robot can be programmed with different toolpaths for different parts, providing flexibility while maintaining machining precision
Solution Approach 2:
The machining system is segmented into independent components (robot arm, spindle, tooling) that can be independently positioned and configured. This modular approach allows the system to adapt to different parts by repositioning components rather than requiring dedicated fixture tooling for each part type
5Adaptability or versatility
If a six-axis joint robot is used to hold the milling cutter, then flexibility is improved, but stiffness decreases when axes move or rotate during milling
Solution Approach 1:
The system uses dynamic control where the robot axes are programmed to maintain fixed positions during the actual milling operation. The flexibility of the robot is utilized for positioning and approach movements, while stiffness is maintained during cutting by holding the axes stationary, eliminating the trade-off between flexibility and stiffness
Data Source
AI summary
An assembly, an apparatus, and a method for machining a mechanical part. The assembly includes a parallel robot adapted to be mounted onto a platform under the mechanical part to be machined. The assembly includes a servo spindle mounted on the parallel robot and configured to drive a machining tool to rotate. The parallel robot is configured to drive the servo spindle to translate along the one or more axes with respect to the parallel robot. During the machining of the mechanical part, the parallel robot may drive the servo spindle to translate along the one or more axes under the mechanical part, such that the machining tool may cut out the required shapes and characteristics at a bottom side of the mechanical part.