Manufacturing a Massive 120-Ton Equipment Frame
The Challenge
A leading global Tier-1 OEM required a massive base frame to support an entire automated assembly line. At 25 meters in length and weighing over 120 tons, the frame needed exceptional structural rigidity. The critical challenge, however, was dimensional accuracy.
The mounting rails along the entire length of the frame had to be perfectly parallel and machined to a flatness tolerance of ±0.5 mm over the entire 25 meters. Standard job shops cannot attempt this because the immense heat generated during welding causes the carbon steel to warp, permanently distorting the mounting pads before machining even begins.
The Openex Solution
Using large-scale profile cutting centers, high-strength low-alloy structural steel plates were precision-cut. We deployed heavy Flux-Cored Arc Welding (FCAW) combined with massive multi-ton overhead cranes and rotators to securely position the heavy beams. Weld seams underwent immediate 100% Ultrasonic Testing (UT) by our in-house inspectors.
To eliminate weld-induced warping during the final machining phase, the entire 120-ton structure was placed inside our massive on-site heat treatment furnace. We conducted a strict, multi-stage Post-Weld Heat Treatment (PWHT) / Stress Relief process to thermally normalize the metal grid.
Finally, the stress-relieved frame was locked down onto our giant 25-meter CNC Gantry Planer Mill. Because all residual stress was eliminated in step 2, the milling head achieved the flawless flatness tolerances required for the OEM’s mounting rails.
Final Specifications & Result
The project was completed under rigorous schedule requirements and delivered to the client’s site via heavy-haul logistics fully primed, painted, and ready for immediate machinery integration.
| Dimensions | 25,000 mm (L) x 4,500 mm (W) x 3,000 mm (H) |
|---|---|
| Total Finished Weight | 120 Metric Tons |
| Base Material | Structural Carbon Steel (ASTM A36 / Q345) |
| Key Machining Tolerance | Rail Flatness: ±0.5 mm over entire length |
| Quality & NDT | 100% UT on structural joints; Dimensional verified by Laser Tracker. |
| Surface Finishing | Steel grit blasted and coated with Industrial Epoxy/Polyurethane system. |