Design Quality Monitoring

1. Desing Stage

(1) TESTING AIRFLOW, AIR PRESSURE AND NOISE AT THE DESIGN STAGE OF FANS AND SHELL TO OPTIMIZE THE PRODUCT FEATURES AND TO SATISFY CUSTOMERS NEEDS.

(2) TESTING LOCKED TEMPERATURE RISE AMBIENT TEMPERATURE 72 HOURS ON/OFF WARMING VERIFICATION AND REVERSE PROTECTION TEST TO VERIFY THE RELIABILITY OF CIRCUIT DESIGN.

(3) THE TESTING INSTRUMENTS AT THIS STAGE ARE

  • TEST ITEMS: INSTRIUMENT USED
  • AIR FLOW AIR FLOW AND PRESSURE TEST SYSTEM
  • AIR PRESSURE AIR FLOW AND PRESSURE TEST SYSTEM
  • NOISE LEVEL: ANECHOIC CHAMBER SOUND METTER FFT ANALYSER
  • LOCKED TEMPERATURE RISE TEST: POWER SUPPLY, TEMPERATURE RECORDER
  • REVERSE PROTECTION TEST: POWER SUPPLY
  • AMBIENT TE MP 72 HOURS ON/OFF: POWER SUPPLY

2. Trial Stage

(1) AFTER COMPLETING MOULD TEST QUALITY VERIFICATION AT TRIAL STAGE AGAINST THE DIMENSION OF INJECTION PRODUCTS AND STRUCTURAL STRENGTH OF ASSEMBLED PRODUCTS.

(2) THE TEST ITEMS AND INSTRUMENTS USED IN THIS STAGE ARE F0LLOWING:

  • TEST ITEMS: INSTRIUMENT USED
  • AIR VOLUME: AIRFLOW AND AIR PRESSURE TESTING SYSTEM
  • STATIC PRESSURE: AIRFLOW AND AIR PRESSURE TESTING SYSTEM
  • NOISE: ANECHOIC CHAMBER SOUND METTER FFT ANALYSER
  • IMPELLER BALANCE: MICROPROCESSOR BALNCER
  • FRAME STRENGHT: POWER SUPPLY PUSH-PULL GAUGE
  • ROTOR PULL-OFF FORCE: PUSH-PULL GAUGE
  • SHELL RIB PRESSURE RESISTANCE: PUSH-PULL GAUGE
  • RUNING TEST AT HIGH TEMPERATURE: TEMP & HUMIDITY CHAMBER POWER SUPPLY
  • FAN MODULAR VIBRATION TEST: VIBRATION TESTER (CONTRACTED OUT)
  • FAN MODULAR SHOCK TEST: SHOCK TESTER (CONTRACTED OUT)

3. Pilot Stage

(1) AT THE PILOT PRODUCTION OF PRODUCTION LINE, CONTROL IS APPLIED TO THE RMP AND CURRENT CHARACTERISTICS OF PRODUCTS

(2) CONDUCT AMBIENT TEMPERATURE/ CEILING WORKING VOLTAGE ON/OFF/24 HOURS WARMING VERIFICATION ON ALL PILOT PRODUCTS

(3) TEST ITEMS AND INSTRUMENT USED AT THIS STAGE

  • TEST ITEMS: INSTRIUMENT USED
  • SPEED: POWER SUPPLY RPM METTER
  • CURRENT: POWER SUPPLY
  • BURN IN 24 HRS AT AMBIENT TEMP: POWER SUPPLY RPM METTER

Mean Time to Failure of Cooling Fan

1. EXPRESSION OF RELIABILITY

(1) (RATE OF FAILURE): MEANS THE POSSIBLE RATE OF FAILURE OF PRODUCT WITHIN A UNIT PERIOD OF TIME. WHICH IS THE REVERSE OF MTTF.

(2) MTBF: (MEAN TIME BETWEEN FAILURE): MEAN TIME BETWEEN FAILURES MEANS THE AVERAGE INTERVAL OF FAILURE AFTER A PERIOD OF SERVICE.

(3) MTTF: MEAN TIME TO FAILURE MEANS THE AVERAGE LIFE OF PRODUCT FROM START TO TOTALLY BREAKDOWN GENERALLY, MTTF STRESSES MORE ON THE FAILURE THAT IS UN-REPAIRABLE AND PRODUCT IS DISPOSED AT FAILURE (IS NOT WORTH TO REPAIRING) FROM THE BASIC DEFINITION, IT IS SIMILAR TO MTBF, BUT DIFFERENCE IS MTBF MEANS REPAIRABLE FAILURE. BUT THE COOLNG FAN IS NOT WORTH REPAIRING AFTER FAILURE. SO MTTF IS MORE APPLICABLE.

(4) LIO: MEANS THE PERIOD OF TIME PRODUCTS ACCUMULATED TO THE 10% FAILURE RATE

(5) RELATIONSHIP BETWEEN VTTF AND LIO: MTTF VALUE IS 9.5 TIMES OF L10

1. ESTIMATE OF MTTF

GENERALLY THE REAL, MTTF OF PRODUCTS ON THE MARKET CANNOT BE CALCULATED, SO THE MTTF IS ESTIMATED UNDER SIMULATED USE THE PRODUCTS HAD TO RUN TO BREAKDOWN AT EACH TEST. IT WOULD NOT MEET THE MARKET DEMAND AS FAR AS THE TIME CONSUMPTION IS CONCERNED. THEREFORE, MIL-HDBK-217F SPECIFICATION IS BASED WITH ARRHENIUS MODEL ACCELERATED TEST MODE THEORY TO INCREASE ENVIRONMENT STRESS TO ACCELERATE THE AGING OF PRODUCT AND TO SHORTEN THE TEST TIME AS WELL AS ESTIMATE THE MEAN TIME TO FAILURE.