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Which is harder, HAST's 96h or Double 85's 1000h?
2025-06-05 14:25:40

Which is harder, HAST's 96h or Double 85's 1000h? The experimental condition strength of HAST at 130 ℃ 85% RH for 96 hours is higher than that of THB at 85 ℃ 85% RH for 1000 hours. The acceleration factors for THB and HAST experiments are both based on the Hallberg Peck model, which can be used to calculate the intensity of HAST96 and Double 85.

We still use the environmental conditions mentioned in AECQ100 for the application of the device, RHu=74%; Tu=32℃; Under the HAST and THB experimental conditions, the calculated acceleration factor Af is as follows:
HAST:130℃,85%RH; Af≈2484
THB:85℃,85%RH;Af≈137
By inputting the corresponding relationship between acceleration factor, testing time, and usage time: Af=t_u/t_t, the theoretical experimental duration required for the 15 year (131400h) service life of HAST 96h and Double 85 can be calculated
HAST:130℃,85%RH,96h; Theoretical experiment duration=131400/2484 ≈ 53 hours; the actual experimental conditions given in AECQ100 are 96 hours.
THB:85℃,85%RH,1000h; The theoretical experimental duration is 131400/137 ≈ 960 hours; the actual experimental conditions given in AECQ100 are 1000 hours.
We can see from the relationship between theoretical calculation time and actual experimental conditions that if we assume that the accuracy of the model is consistent under two experimental conditions, then the experimental intensity of HAST 130 ℃, 85% RH, and 96 hours is indeed significantly higher than that of THB 85 ℃, 85% RH, and 1000 hours.
From a practical application perspective, both experimental conditions have a humidity of 85% RH. In terms of temperature, THB used 85 ℃, which is closer to the temperature of the car engine compartment, while the HAST experiment used 130 ℃. The Tg temperature of the epoxy resin we commonly use is usually between 110 ℃ and 150 ℃. Obviously, THB has a more sufficient margin of 85 ℃, and HAST's 130 ℃ is closer to the Tg temperature and may even exceed it. Therefore, HAST96 is more likely to cause delamination and other failures that do not meet the actual application conditions (which may be the reason why many packaging factories do not pay attention to delamination after HAST experiments). Therefore, in terms of possible additional failures, HAST96 is also stronger than Double 85.