Meaning
Precision measurement of material thickness using the time of flight of sound waves provides a continuous monitoring method for the wear of tooling in battery production. Ultrasonic thickness scanning works by sending a high frequency sound pulse through a material and measuring the time it takes for the echo to return from the opposite surface. This technique allows for the inspection of parts where only one side is accessible, such as the walls of a cooling manifold or the base of a deep drawn cell can.
It is much faster than manual gauging and can be automated to provide real time data on the manufacturing process. The measurement is accurate until the surface becomes too rough or the material becomes too thin to resolve the echo.
Measurement Principle
Velocity of sound in the specific material must be known to convert the time of flight into a precise thickness value. Ultrasonic thickness scanning relies on a transducer that both sends the signal and receives the reflected pulse. A couplant is used to eliminate the air gap between the probe and the part to ensure the sound enters the material.
If the sound speed changes due to temperature variations, the system must be recalibrated to maintain accuracy.
Precision Factor
Resolution of the measurement is determined by the frequency of the transducer, with higher frequencies providing better detail on thin materials. Ultrasonic thickness scanning can detect variations of just a few microns, which is essential for ensuring the uniformity of battery current collectors. This precision allows for the detection of gradual tool wear before it results in parts that are out of tolerance.
The system can also identify internal corrosion or thinning that might lead to a leak in the cooling system.
Tooling Maintenance
Data collected from these scans is used to schedule the regrinding or replacement of stamping dies and drawing punches. Ultrasonic thickness scanning provides a non destructive way to monitor the health of the production equipment without stopping the line. If the thickness of the parts begins to trend towards the limit, the maintenance team is alerted to investigate the cause.
This proactive approach reduces the amount of scrap and ensures that the battery housings meet the strict safety standards. The final scan provides a record of the part quality that can be traced back to the specific production lot.
