Post-weld grinding remains an often-overlooked challenge in shipbuilding. While significant efforts are made to improve welding efficiency, the costly and time-consuming process of grinding after manual welding continues to be a hidden burden. Excess weld material and defects such as undercut require extensive grinding, adding unnecessary labor costs, increasing production time, deteriorating the shop primer, and generating harmful dust and noise in shipyards.
The Root Cause: Inconsistencies in Manual Welding
One of the primary reasons for post-weld grinding is the inherent variability in manual welding. Differences in heat input, torch angles, welding stick-out, and welding speed—caused by individual welders’ personal techniques—may result in excessive reinforcement or poor fusion. These inconsistencies necessitate additional post-processing to ensure weld and surface quality.
A study by the National Shipbuilding Research Program (NSRP) revealed that shipyards dedicate substantial labor hours to grinding tasks, including the removal of mill scale, slag, paint, weld spatter, undercut, and weld scars from steel surfaces. These additional steps add to production time and costs while also impacting on worker safety and environmental conditions.
Eliminating Post-Weld Grinding with Robotic Welding
Advanced robotic welding solutions allow shipyards to eliminate the need for post-weld grinding altogether. By precisely controlling welding parameters and torch positions, robotic welding ensures smooth, high-quality welds with minimal excess material, reducing the need for corrective post-processing. This not only accelerates ship production but also fosters a safer, cleaner, and more cost-efficient work environment, while enhancing the perceived quality of the final product.
How Inrotech Robots Prevent Undercut
- Optimal Torch Angle and Positioning: The Inrotech SensLogic software contains a library of predefined welding techniques tailored to various ship design features. By selecting the correct feature through sensing, the robot automatically applies well-proven torch angles and movements to fill the joint properly without defects.
- Automated Parameter Control: The robotic welding system continuously monitors and adjusts voltage, amperage, and wire feed speeds to maintain optimal welding conditions, preventing excessive melting (bulging) or undercut formation.
- Arc Sensor-Based Tracking: The seam tracking software continuously monitors welding parameters, adjusting the robot’s path in real time to compensate for inaccuracies and distortions happening during welding. This ensures accurate centering of the tool center point (TCP) and eliminates quality defects.
Benefits of Eliminating Post-Weld Grinding
By ensuring defect-free welds, Inrotech’s robotic solutions remove the need for grinding, leading to significant advantages:
- Time Savings: Eliminating grinding reduces overall welding time, allowing for faster project completion. Material Efficiency: Optimized welding reduces excess material use, eliminating unnecessary removal steps.
- Reduced Quality Control Effort: With highly consistent robotic welds, only statistical quality control checks are required.
- Improved Health & Safety: Grinding produces hazardous dust and fumes. Removing this step enhances workplace air quality and reduces health risks for shipyard workers.
- Cost Reduction: Lower consumption of welding wire, grinding discs, and electricity leads to significant cost savings. Additionally, reduced labor time lowers overall production expenses.
- Maintain surface corrosion resistance: Prevent that grinding of the shop primer deteriorates the surfaces resistance to corrosion.
- Enhanced Work Environment: Removing grinding improves noise levels and overall working conditions for shipyard personnel.
Note: It is extremely important that when introducing robots, the routine of grinding weld seams is eliminated (as it is no longer necessary) from the standard operating procedures and the habits in the factory, thereby ensuring that the full benefit of robotic welding is captured.
Applications of Automated Welding in Shipbuilding
Automated welding is particularly valuable in shipbuilding, where large structures demand precise, consistent welds. Key applications include:
- Seam welding in ship panels and sections
- Welding of hull structures, decks, and bulkheads
- Fillet and butt welding in stiffeners and frames
- Welding in confined and hard-to-reach areas within ship or offshore interiors
Advanced Welding Solutions from Inrotech
Inrotech offers cutting-edge robotic welding solutions tailored to the shipbuilding industry. Two of the most advanced systems—Inrotech-Classic and Inrotech-MicroTwin—are autonomous robotic welding systems designed to navigate complex ship structures with ease. Key Features of Inrotech Robotic Welding Solutions:
- Adaptive Intelligence: Automatically adjusts to variations in weld joints, ensuring optimal quality.
- Compact & Mobile Design: Easily navigates confined spaces in shipbuilding environments.
- Fully Automated Operation: Requires minimal human oversight, maximizing efficiency and reducing dependency on skilled welders.
- High-Precision Welding: Delivers consistent, top-quality welds, minimizing rework and ensuring durable, defect-free ship structures.
