Zhuojin Pipe Fitting Co., LtdWelding Path Planning in Remanufacturing Forming Systems
Literature Overview
This paper by Liang Yuanyuan and Zhu Sheng, published in "China Surface Engineering" (2006, Vol. 19, Z1, pp. 274-276), originates from the National Key Laboratory of Equipment Remanufacturing Technology. The work addresses the challenge of welding path planning for robotic MIG welding in a remanufacturing forming system, where worn or damaged components are restored to original or improved specifications through additive welding. The paper describes the principles of path planning, derives a series of planning parameters, calculates and compares weld overlap ratios, and presents a software implementation that successfully guided overlay repair of parts.
Technical Context and System Architecture
Equipment remanufacturing is a sustainability-driven manufacturing philosophy that extends the service life of mechanical components by removing worn material and rebuilding the surface geometry through welding. The system described in the paper integrates three key subsystems: system calibration, part scanning and modeling, and robotic welding execution. The welding path planning module serves as the critical link between the digital model of the damaged component and the physical welding operation.
| System Component | Function | Key Technology |
|---|---|---|
| System calibration | Establish coordinate relationships | Laser tracker, reference targets |
| Part scanning | Capture 3D geometry of damaged surface | Structured light or laser scanning |
| CAD modeling | Generate repair geometry | Reverse engineering software |
| Path planning | Generate robot trajectories | Kinematic modeling, toolpath optimization |
| Welding execution | Deposit weld metal along planned path | Robotic MIG welding system |
Path Planning Principles and Parameters
The path planning algorithm described in the paper operates on the principle of decomposing the repair volume into a series of discrete weld beads, each of which is executed as a continuous robot trajectory. The key planning parameters include bead width, bead height, travel speed, overlap ratio between adjacent beads, and the starting and ending positions of each bead. The overlap ratio is defined as the fraction of the previous bead's width that is covered by the next bead, and it directly affects weld bead uniformity, dilution, and the mechanical properties of the deposited material.
The paper presents a systematic comparison of different overlap ratios and their effects on welding outcomes. Insufficient overlap results in gaps between beads, leading to porosity and reduced load-bearing capacity. Excessive overlap increases the total heat input, promotes dilution of the base metal, and can cause distortion or cracking in the deposited layer. The optimal overlap ratio must balance these competing factors, and the paper's analysis provides quantitative guidance for this optimization.
Software Implementation and Practical Outcomes
The software implementation described in the paper translates the planned trajectories into robot control commands, accounting for the kinematic constraints of the specific welding robot used. The system successfully guided overlay repair operations on actual components, demonstrating that the planning methodology is not merely theoretical but practically viable. The good results reported suggest that the integration of scanning, modeling, planning, and execution into a unified system is feasible and effective.
Engineering Practice and Reflective Insights
From a manufacturing engineering perspective, this paper addresses a critical bottleneck in the remanufacturing industry: the difficulty of translating complex 3D repair geometries into executable welding programs. Manual programming of robotic weld paths for irregular surfaces is time-consuming, error-prone, and requires highly skilled programmers. The automated path planning approach described here significantly reduces programming time and improves consistency.
In my experience with robotic welding systems for pipe repair and overlay welding, the challenge of path planning is compounded by the need to maintain consistent weld quality across varying surface geometries. The overlap ratio optimization presented in this paper is directly applicable to overlay welding scenarios in pressure vessel repair, where the deposited layer must have specific mechanical properties and corrosion resistance. The paper's methodology provides a solid foundation for developing more sophisticated path planning algorithms that can adapt to real-time feedback from in-process monitoring systems. The integration of scanning-based digital twin technology with robotic welding represents a significant advancement in the field of equipment remanufacturing.