Low air velocity in the working space refers to the adjusted airflow velocity of the working space, which can maintain the set conditions, but is also low enough that the temperature at any point on the test sample is not affected by the air circulation. And reduce by more than 5K (if possible, no more than 0.5m / s). Low air velocity in the working space refers to the adjusted airflow velocity of the working space. In order to maintain the set conditions, the arbitrary temperature on the test sample is reduced by more than 5K due to the influence of air circulation. Non-heat-dissipation test sample and heat-dissipation test sample test method application comparison General: High-low temperature test chamber manufacturing and validation GB/T2424.5 and GB/T2424.7 provisions.
2) For the high temperature and low temperature test guidelines, see GB/T2424.1, and for general, see GB/T2421. 3) The test sample is considered to be heat dissipated only when the temperature is stable (see GB/T2421 for details). The hottest temperature on the surface of the test sample measured under free air conditions (for example, low air flow rate circulation) exceeds the air temperature around the test sample by more than 5K. The low temperature test Ab is applicable when the relevant specification requires a storage or transport test, or if no load is specified during the test. The high and low temperature test chambers are determined in the working space for high airflow speed or low airflow speed under standard environmental conditions for measurement and testing (see GB/T2421), and airflow speed <0.2 m/s, according to the low temperature condition to be tested. The following provisions energize the test sample or add an electrical load.
When the temperature of the test sample is stable, the temperature of several representative locations on or around the test sample should be measured using a suitable monitoring device. After that, the temperature rise of each location should be recorded. Turn on the ventilation of the high and low temperature test chamber to circulate the air
When the temperature reaches a steady state, re-measure the temperature at the above position. If the measured temperature differs from the temperature measured during the last airless air flow by more than 5K (or other values ​​specified in the relevant specifications), these temperature values ​​shall be recorded in the test report and the high and low temperature test chamber is considered to be high. Airflow speed cycle. The test sample is then powered down and any load conditions are removed.
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|
Item |
Unit |
Index |
Test condition |
|
|
Thickness tolerance |
% |
≤3 |
GB/T6682-2001 |
|
|
Transmittance |
% |
≤2 |
GB/T 2410-2008 |
|
|
Tensile strength
|
MD |
Mpa |
≥170 |
GB/T 1040.3 |
|
TD |
Mpa |
≥170 |
||
|
Elongation at Break |
MD |
% |
≥90 |
GB/T 1040.3 |
|
TD |
≥90 |
|||
|
Heat shrinkage (150℃30min) |
MD |
% |
≤1.4 |
GB/T 16958-2008 |
|
TD |
≤0.2 |
|||
|
Haze
|
% |
≥98 |
GB/T 2410-2008 |
|
|
Gloss |
% |
≥100 |
GB/T 2410-2008 |
|
|
Surface tension |
Dyn/cm |
≥52 |
GB/T 14216-2008 |
|
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