The welding quality of the car seat air bag directly affects the performance, safety and service life of the ventilation system. To ensure that the welding quality meets the standards, a complete quality assurance system needs to be built from four dimensions: equipment performance, process control, material adaptation, and testing and verification. The following are specific measures and analysis:
1. Equipment performance guarantee
Selection of high-precision welding equipment
Core parameters of high-frequency heat sealing machine:
Frequency stability: error ≤±0.5%, ensuring uniform distribution of welding energy.
Pressure control accuracy: ±0.1MPa, avoiding false welding or material damage due to pressure fluctuations.
Temperature closed-loop control: temperature fluctuation range ≤±2℃.
Equipment function configuration:
Spark protection system: response time ≤0.01 seconds to prevent material burn-through.
Pressure balance device: dual cylinder synchronous pressurization to ensure uniform force on the welding surface.
Equipment maintenance and calibration
Regular calibration plan:
Monthly test the accuracy of pressure sensors and temperature probes.
Management of wearing parts:
Establish life files for components such as electrode plates and molds, and replace worn parts in time.
2. Process parameter control
Optimization of key process parameters
Parameter item Standard range Key points of process control
Welding time 1.5-3.0 seconds Dynamic adjustment according to material thickness
Welding pressure 0.3-0.6MPa Pressurization in stages (pre-pressing → welding → holding pressure)
Cooling time 2-5 seconds Prevent material deformation
Standardization of process documents
Compilation of the "Automotive Seat Air Bag Welding Operation Guide" to clarify:
Process parameters for different material combinations (such as TPU/TPU, TPU/PVC).
Welding sequence (such as welding the long side first and then the short side).
Abnormal handling process (such as repair welding specifications during flashover).
3. Material and mold adaptation
Material quality control
Incoming material inspection:
Test the melt index (MFR) and elongation at break of the TPU film.
Verify the uniformity of the mesh cloth aperture (error ≤±5%).
Material compatibility test:
Carry out small sample welding tests on different batches of materials to confirm the optimal process window.
Mold design and maintenance
Mold design principles:
Weld line width ≥3mm to ensure sealing.
Mold surface roughness Ra≤0.8μm to reduce the risk of adhesion.
Mold management:
Establish a mold resume to record the number of uses and maintenance records.
Use nitriding or hard chrome plating to extend the life of the mold.
4. Quality inspection and verification
Process inspection
First piece inspection: The first product of each shift is 100% inspected, focusing on the following inspections:
Weld strength (tensile test ≥15N/cm).
Air tightness (negative pressure for 30 seconds, pressure drop ≤0.5kPa).
Online monitoring:
Install pressure sensors and displacement sensors to collect welding data in real time.
Set up SPC control charts to monitor process stability.
Finished product inspection
Full inspection items:
Appearance defects (no burning, burrs, wrinkles).
Dimensional accuracy (diagonal error ≤±1mm).
Sampling items:
Durability test (simulate 5-year use cycle, 100,000 cycles of inflation and deflation).
High and low temperature cycle test (-30℃~80℃, 200 hours).
5. Personnel training and management
Operator qualifications
Welders must undergo training and pass the assessment before they can take up their posts.
Skills review is conducted every year to assess practical operation ability and quality awareness.
Quality culture construction
Implement a quality traceability system, and bind operators, equipment, and process parameters to each product.
Carry out quality improvement proposal activities to encourage employees to participate in process optimization.
Conclusion
The quality problem of automobile seat airbag welding can be systematically solved through five measures: equipment accuracy assurance, closed-loop control of process parameters, standardized management of materials and molds, full-process testing and verification, and personnel capacity improvement. It is recommended that enterprises establish a welding quality database, continuously optimize the process through big data analysis, and ultimately achieve the quality goals of a welding pass rate of ≥99.5% and a customer complaint rate of ≤0.1%.