The spray gun angle adjustment mechanism of a sandblasting robot requires a multi-dimensional design to adapt to varying workpiece curvatures. The key lies in achieving dynamic angle adjustment, precise trajectory planning, and coordinated matching with the workpiece curvature. This process involves the integrated application of mechanical structure, control system, and sensor technology to ensure the spray gun maintains the optimal spraying posture even when machining complex curved surfaces.
In terms of mechanical design, sandblasting robots often employ a multi-jointed robotic arm or a rotating spray gun holder, driven by a servo motor for continuous angle adjustment. For example, some models incorporate a cam swing mechanism at the end of the spray gun, utilizing a roller-driven disc cam to achieve ±35° reciprocating oscillation. A planetary gear reducer and synchronous belt drive ensure a stable oscillation cycle. This design enables the spray gun to automatically adjust the spray direction based on changes in workpiece curvature, avoiding localized excessive wear or insufficient treatment caused by a fixed angle. For surfaces with large curvatures, the spray gun holder can be designed with a retractable structure, using a pneumatic cylinder or electric actuator to adjust the spray distance, ensuring that the abrasive flow remains perpendicular to the surface normal.
The control system is crucial for spray gun angle adjustment. Modern sandblasting robots generally utilize PLC or CNC systems, combined with offline programming techniques, to pre-set spray gun trajectories for workpieces with varying curvatures. For example, for disc-shaped workpieces, the system uses a rotary encoder to monitor the turntable's rotational speed in real time and synchronously adjusts the spray gun's oscillation frequency to align the spray trajectory with the workpiece's rotational period. For irregularly shaped workpieces, a visual recognition system captures surface feature points and generates a three-dimensional spray gun path, ensuring the optimal spray angle for each curvature region. Some high-end models also incorporate force feedback control, using sensors to monitor the contact force between the spray gun and the workpiece surface and dynamically adjust the spray angle to avoid deviations caused by sudden changes in curvature.
The application of sensor technology further enhances the accuracy of angle adjustment. Laser displacement sensors measure the workpiece's surface curvature radius in real time, feeding this data back to the control system to drive micron-level adjustments to the spray gun holder. Pressure sensors monitor the impact force of the abrasive stream. When changes in curvature cause fluctuations in impact force, the system automatically optimizes the spray angle and air pressure to maintain consistent treatment results. In addition, some robots are equipped with multi-axis accelerometers. By monitoring the motion of the robotic arm, they can predict curvature trends and adjust the spray gun angle in advance, reducing response delays.
Optimizing process parameters for workpieces with different curvatures is also crucial. For workpieces with small curvatures (such as cylinders), fixed-angle spraying can be used, with uniform treatment achieved by increasing the turntable speed or the spray gun's oscillation frequency. For workpieces with large curvatures (such as spheres), the spray angle needs to be dynamically adjusted, combined with variable-pitch spraying technology, to maintain a constant impact force across areas of varying curvature. For workpieces with complex curvatures (such as turbine blades), the system uses a layered processing strategy, dividing the surface into multiple curvature zones and setting the optimal spray angle and pressure for each zone to ensure surface roughness meets the required standards.
In practical applications, the angle adjustment mechanism of the sandblasting robot must also consider the matching of abrasive properties with the workpiece material. For example, when processing high-hardness workpieces, the spray angle needs to be increased to enhance impact force, while the distance between the spray gun and the workpiece surface needs to be adjusted to prevent abrasive rebound. When processing thin-walled workpieces, the spray angle needs to be reduced to minimize the risk of localized stress concentration. Furthermore, the abrasive type (e.g., steel grit, glass beads) and particle size also influence angle adjustment strategies. Fine-grained abrasives require more precise angle control to prevent embedding into the workpiece surface.
The sandblasting robot's spray gun angle adjustment mechanism achieves efficient adaptation to varying workpiece curvatures through innovative mechanical structure, intelligent control systems, and integrated sensor technology. This technology not only improves surface treatment quality but also expands the sandblasting robot's application in complex curved surface machining in the aviation, automotive, and energy sectors.
