An in-Contact Robotic System for the Process of Desoldering PCB Components

TL;DR

This work tackles automated PCB component dismantling to advance e-waste recycling. It introduces a six-phase in-contact desoldering workflow where a 6-DOF collaborative robot uses a custom push-pull desoldering tool and Cartesian force control with a desired end-effector force $f_d$ to detach components while preserving PCB integrity. The system integrates a heated desoldering setup and a force-sensing framework that detects contact via $F_{z,b,t}$ and solder melting via $F_{y,c,t}$, achieving approximately 100% desoldering success for larger components and about 50% grasping success, with limitations from neighboring components. Future work includes a second robotic arm for heating and computational vision for component pose and classification to improve autonomy and robustness.

Abstract

The disposal and recycling of electronic waste (e-waste) is a global challenge. The disassembly of components is a crucial step towards an efficient recycling process, avoiding the destructive methods. Although most disassembly work is still done manually due to the diversity and complexity of components, there is a growing interest in developing automated methods to improve efficiency and reduce labor costs. This study aims to robotize the desoldering process and extracting components from printed circuit boards (PCBs), with the goal of automating the process as much as possible. The proposed strategy consists of several phases, including the controlled contact of the robotic tool with the PCB components. A specific tool was developed to apply a controlled force against the PCB component, removing it from the board. The results demonstrate that it is feasible to remove the PCB components with a high success rate (approximately 100% for the bigger PCB components).

Figures (6)

• Figure 1: Schematic of the system highlighting the main hardware elements.
• Figure 2: Representation of the forces acting on the tool during the contact with the PCB component and its representation at the robot end-effector level.
• Figure 3: Robot control architecture.
• Figure 4: Schematic of the push-pull mechanism in which the tool connectors (1) are attached to the gripper fingers. Through contact, the tool can desolder the PCB component and grasp it. The tool main design elements are the connectors to the gripper fingers (1), the sliding mechanism that allows the lower and upper bars to slide at a set distance, the lower and upper bars (3), the element that contacts with the PCB component to desolder it (4), and the element that ensures the grasping (5).
• Figure 5: Experimental setup of the system highlighting the in-contact desoldering of a PCB component (left) and the grasping of such component (right). The system is composed by the gripper (1), the tool (2), the hot plate (3) and the PCB component (4). The bottom figure shows the PCB of a mobile phone.