恒溫恒濕試驗(yàn)箱循環(huán)試驗(yàn)失效原因解析
恒溫恒濕試驗(yàn)箱循環(huán)試驗(yàn)失效原因解析
Constant temperature and humidity test chamber also known as "high low temperature alternating test chamber", based on inligent instrument, screen can be set program loop test, in test phase, there is a cycling test fails, the following by the constant temperature and humidity test chamber production experts - Beijing hong da day torque test equipment co., LTD., analyzes the failure reason:
1, the basic parameters: the temperature cyclic stress mainly has six basic parameters:
(1) ceiling temperature;
(2) the lower temperature;
(3) temperature change rate;
(4) limit temperature holding time;
(5) the lower temperature holding time; 6 cycles.
2, temperature cycle stress characteristic: in the temperature cycling test, constant temperature and humidity test in the airflow uniformity is an important parameter, this parameter will influence the temperature change rate of the products.
恒溫恒濕試驗(yàn)箱 又名“高低溫濕熱交變?cè)囼?yàn)箱”,采用觸摸屏智能型儀表,可設(shè)定程序循環(huán)試驗(yàn),在試驗(yàn)進(jìn)行階段,有一種循環(huán)試驗(yàn)失效,下面由恒溫恒濕試驗(yàn)箱生產(chǎn)專(zhuān)家-北京鴻達(dá)天矩試驗(yàn)設(shè)備有限公司對(duì)失效原因進(jìn)行分析:
1、溫度循環(huán)應(yīng)力基本參數(shù):基本參數(shù)主要有6個(gè):①上限溫度;②下限溫度;③溫度變化速率;④上限溫度保溫時(shí)間;⑤下限溫度保溫時(shí)間;⑥循環(huán)次數(shù)。
2、溫度循環(huán)應(yīng)力特性分析:在溫度循環(huán)試驗(yàn)中,恒溫恒濕試驗(yàn)箱內(nèi)的氣流均勻度是一個(gè)很重要的參數(shù),該參數(shù)將影響產(chǎn)品的溫度變化速率。這就要求在多個(gè)試驗(yàn)產(chǎn)品同時(shí)進(jìn)行試驗(yàn)時(shí),試驗(yàn)產(chǎn)品之間、試驗(yàn)產(chǎn)品和試驗(yàn)箱壁之間應(yīng)有適當(dāng)?shù)拈g隔,以便氣流能在試驗(yàn)產(chǎn)品之間、試驗(yàn)產(chǎn)品和箱壁之間自由循環(huán)。
3、溫度循環(huán)應(yīng)力誘發(fā)失效的機(jī)理及敏感元件:溫度循環(huán)使不同膨脹系數(shù)的不同材料的膨脹情況不同,造成剝離、開(kāi)裂、其敏感元件如油漆涂覆層等。
3.1溫度循環(huán)使螺絲連接或鉚接不牢的接頭松馳,其敏感元件如螺絲、鉚接部件等;
3.2溫度循環(huán)使機(jī)械張力不足的壓配接頭松馳;高低溫交變?cè)囼?yàn)箱溫度循環(huán)使材質(zhì)差的釬焊接觸電阻加大或誘發(fā)開(kāi)路,其敏感元件如電阻元件等;
3.3溫度循環(huán)使觸點(diǎn)腐蝕和污染,其敏感元件如合金材料等。