The welding quality directly affects the sealing, durability and safety of the car seat airbag, and it is necessary to ensure that it meets the standards through systematic testing and verification. The following provides a feasible solution from the perspectives of testing methods and testing processes, combined with industry practices and standard requirements.
1. Welding quality testing method
Appearance testing
Test content:
Whether the weld surface is flat, without scorching, burrs, wrinkles or delamination.
Whether the welding edge is neat and there is no excess material residue.
Testing tools:
Visual inspection (with a strong flashlight).
A magnifying glass (more than 10 times) to check for minor defects.
Dimensional accuracy testing
Test content:
Whether the weld width and length meet the requirements of the design drawings (error ≤±1mm).
Whether the overall size of the airbag (such as diagonal, circumference) is within the tolerance range.
Testing tools:
Caliper, micrometer, projector or three-coordinate measuring instrument.
Air tightness test
Testing method:
Negative pressure holding method: After sealing the air bag, evacuate to -50kPa, hold the pressure for 30 seconds, and the pressure drop is ≤0.5kPa for passing.
Positive pressure inflation method: Fill with 0.1MPa compressed air, immerse in water to observe bubbles, and pass if there are no continuous bubbles.
Testing equipment:
Air tightness tester (accuracy ±0.1%FS).
Weld strength test
Testing method:
Peeling test: Peel along the weld direction at a speed of 50mm/min, and record the peeling force (≥15N/cm is qualified).
Burst test: Continue to inflate until the air bag ruptures, and record the bursting pressure (should be ≥2 times the design pressure).
Testing equipment:
Tensile testing machine (range 0-500N, accuracy ±0.5%).
Durability test
Testing method:
Cyclic inflation and deflation test: Simulate a 5-year use cycle, inflate and deflate 100,000 times at a frequency of 0.1Hz, and check whether the weld is cracked or leaking.
High and low temperature cycle test: -30℃ for 2 hours → 80℃ for 2 hours, 200 cycles, detect changes in weld performance.
Testing equipment:
Fatigue testing machine, high and low temperature test chamber.
2. Testing process and standards
First piece inspection
Applicable scenarios: After starting the machine, changing materials or process parameters in each shift.
Inspection items: appearance, size, airtightness, weld strength (100% full inspection).
Process inspection
Inspection frequency: 1 sampling every 2 hours, 5 pieces each time.
Inspection items: appearance, size, airtightness (sampling ratio ≥ 20%).
Finished product full inspection
Inspection items: appearance, size, airtightness (100% full inspection).
Record requirements: Bind the inspection data for each product to achieve quality traceability.
Shipping sampling inspection
Sampling ratio: According to GB/T 2828.1-2012 standard, general inspection level II, AQL=1.0.
Inspection items: appearance, size, air tightness, weld strength (destructive testing can be exempted, but samples must be retained for inspection).