Vacuum Brazed Aluminum Thermal Plate Inspection and Joint Quality Testing
Vacuum brazed aluminum plate acceptance demands 100 percent inline ultrasonic C-scan inspection and helium leak validation below 10-6 mbar L/s to prevent field coolant leaks.
LTPD Sampling
Meaning
Statistical quality control method that defines the poorest quality level a consumer is willing to accept for a single lot. Use of ltpd sampling protects the buyer by ensuring that batches with a high percentage of defects are rejected with a high degree of confidence. This approach contrasts with systems that focus only on the average quality produced over a long period.
Rejectable Quality
Definition of the limit involves picking a percentage value that represents the threshold of failure for the incoming batch. If the ltpd sampling plan is set at five percent, the consumer wants to be sure that any lot with five percent or more defective units is caught. This level is a negotiated point in a supply contract between a cell maker and an automotive manufacturer.
Risk Profile
Probability of accepting a bad lot (known as consumer risk) is typically set at ten percent for these calculations. An ltpd sampling plan requires a specific sample size and an acceptance number of allowed defects to meet this risk target. Larger sample sizes are necessary when the gap between the expected quality and the limit is narrow.
Batch Acceptance
Inspectors draw a random set of components from the delivery and count the number of failures against the plan. If the number of defects found during ltpd sampling exceeds the allowed count, the entire lot is returned to the supplier. This pressure encourages manufacturers to maintain tight control over their production lines to avoid the cost of rejected shipments.
Statistical rigor in the sampling plan ensures that substandard battery components do not reach the assembly line.