Product Introduction
During the production process of a car’s body-in-white (BIW), traditional and handheld detection equipment is still used in the weld point inspection stage. However, there is significant room for improvement in production cycle time, data traceability, and detection rates. Fully automated body welding point inspection technology can effectively address these shortcomings, ensuring that the test results meet the requirements of the spot-welding process.
Four-Arm Robot Solution
The diagram shows that the four-arm robot solution is designed for inspection needs, while the single-arm robot system is more suitable for offline inspection scenarios. The four-arm robot system is applicable for tasks such as full vehicle frame inspection and online sampling inspections. This system can inspect over 80% of the welding points on the vehicle frame.
Systematic deep learning
After every complete cycle of inspecting 1,000 sets of welding points, the system compares the appearance, position, weld nugget, and corresponding welding gun parameters in the data samples. It helps users identify the optimal parameter solutions, while the system also automatically upgrades its inspection standards. Precision calibration is required after each probe has completed 500,000 inspections.
Conclusion： In summary, the fully automated body welding point inspection system can greatly enhance the welding process for vehicle bodies. It forms a closed-loop feedback system with the welding system, promptly reporting the quality of current weld points to allow adjustments to welding parameters or alert operators to make timely corrections. This, in turn, improves the overall safety of the vehicle.
Composition of the Master Control System
The entire system connects the master control system with distributed slave stations through a TCP/IP network. The inspection results are updated in real time to a local database and can also be uploaded to a remote cloud. Mobile devices can access the cloud server to display the data online. The real-time inspection results are also fed back to the welding system, enabling it to adjust welding parameters in real-time.
Definition of a Weld Point Inspection Cycle
A complete weld point inspection cycle theoretically takes 4-5 seconds. This includes:
– 0.5 to 1 second for the visual system to assess the appearance and positioning.
– 3 seconds for eddy current testing to determine the weld point quality.
– 1 second for the robot to switch points, considering the interlocking between robots.
Based on this, in a typical production scenario, such as an online four-arm detection station installed at the end of a welding system, where 800 cars are produced per day on a single production line, and each workstation allows 40 seconds per station, approximately 40 weld points can be inspected per station. This results in a total of 32,000 weld points inspected per day.
Comparison with Handheld Inspection Devices
Handheld inspection devices offer some improvement over traditional manual testing. However, they still require manual labor in smart manufacturing environments, have slower inspection speeds, and cannot provide immediate feedback to the welding system for timely adjustments in the upstream welding process.
Traditional Manual Weld Point Inspection Method
In traditional manual destructive weld point inspection, the operator physically breaks the weld point and judges the weld quality based on experience. This method significantly increases the workload and introduces a level of subjectivity, as judgment is prone to error. Additionally, once a weld point is broken, the parts or even the entire vehicle may be wasted, resulting in resource loss.
Work equipment
The workstation contains the following equipment：
- Electric control cabinet
- Robot control cabinet
- Servo control cabinet
- Distributed IO control cabinet
- System workstation
- ABB Robot
- Inspection parts
- Transport trolley
- Servomotor
- Safety fence
The entire system is composed of a master control system and distributed slave stations. The master control system uses a Siemens PLC, while the distributed slave stations include robots, servo motor systems, a visual inspection module, an eddy current inspection module, external field IO, and on-site HMIs (Human-Machine Interfaces).
Definition of Workstation Conditions: The fully automated body weld point inspection system can be installed at the end of a welding system as an in-line inspection station, or it can be installed on a by-pass line for offline sampling inspections. A typical inspection workstation with four robots requires a 6m x 6m space.
Working Principles and Technical Areas Covered
Solutions
Single-Robot Station
Inspection Options:
- Capable of inspecting up to 20 weld points in 100 seconds.
- Primarily aimed at customers who need to inspect individual parts or specific sections of the car body.
- Can perform in-line or by-pass inspections; in-line for single item inspection.
Space Requirement:
- Minimum of 6m x 6m
- Safe and clean production areas
- Designated locations for the power supply, master control cabinet, and robot control cabinet.
Four-Robot Station
Inspection Options:
- Capable of inspecting up to 80 weld points in 100 seconds
- Covers 90-95% of the vehicle body.
- Mainly for customers requiring full vehicle body inspection
- Can perform in-line or by-pass inspections.
Space Requirement:
- Minimum of 6m x 6m
- Safe and clean production areas
- Designated locations for the power supply, master control cabinet, and robot control cabinet.
Project Features Summary
- Four robots can complete the inspection of 250 weld points in just 5 minutes.
- Significantly reduces labor and material costs.
- Automated weld point inspection provides more consistent results than manual methods.
- Capable of performing a full inspection of vehicle body weld points.
- Utilizes array-based eddy current sensors.
- Incorporates various visual techniques and core algorithms.
- Provides real-time feedback on body welding production and electrode cap replacement.
- Enhances the traceability of spot weld quality for vehicle bodies.
