Study on the solution to the problem of venting of venting holes in appliance products
Heating is the current flowing through the conductive liquid to make it work. Once the charged liquid flows out through the vent hole, the user may get an electric shock or burn. We can see that among the 20 groups of samples, 17 groups did not pass the electrical strength and leakage current test due to the venting of the vent hole, and the input power failed because the electrode was working in the conductive liquid. Due to the temperature change, the resistance of the conductive liquid changes, which causes a very large change in the input power. In the detection, we see that the input power of some products is 2 to 3 times larger than the nominal power. In order to reduce the cost, some manufacturers only connect a thermostat in series in the structural design of the electric heating bag, which acts as both a temperature control device and a protection device. Once the abnormality test is performed, the thermostat is short-circuited. It will always be in a state of charge, the liquid will overheat and swell, causing a burst, and the high temperature liquid will splash out. For the "electric wire type" electric heating bag: the three major unqualified items have nothing to do with the structure. As can be seen from the material, the 13.1% failure of the "electrode type" electric heating bag was caused by the failure of the heat resistance and flame resistance test of the material.
The specific analysis is mainly due to the failure of the power supply terminal or the electrical input of the appliance input socket to withstand the ball pressure test of 125 ° C and the glow wire test of 750 ° C, indicating that the selected materials have poor heat and flame resistance. At higher temperatures, there is a risk of deformation and burning of the insulating material. In addition, two of the other unqualified items are caused by the rated current of the appliance being greater than or equal to 3A, and the diameter of the power cord is not up to 0.75mm2 as required by the standard. This may cause fire due to abnormal heating of the power cord. The signs and input powers from 1 and 2, we see that the difference between 9.5% and 31.8% respectively is due to the signage. Mainly the information on the logo is incomplete. IEC 60335-1:2001+A:2004 Section 7.1 expressly requires the following markings: rated voltage or rated voltage range, power supply property symbol, rated input power, manufacturer's name, trademark or identification mark, appliance type or specification, class II appliance Have a "back" symbol and other content. Of the two types of samples we examined, 8 of the 20 groups and 7 of the above groups did not meet the requirements.
Mainly due to the manufacturer's lack of understanding of the standard requirements. Above we mentioned that the "electrode type" electric heating bag accounted for 16.7% of the input power failure due to its structural reasons, and the "electric wire type" electric heating bag input power has a frequency of 22.7%, which is unqualified. The reason is that the manufacturer arbitrarily changes the indicated power in order to meet the input power values ​​required by different customers. However, the actual test power of the appliance is not marked, so that the measured power and the indicated power are too large, exceeding the allowable error of the standard. Solution Through the above analysis of the main quality problems of the products, we can see that although there are many unqualified items listed in 1 and 2, they are summarized into three categories, namely: structure, materials, signs and inputs. Power problem. From the statistical data, the total number of unqualified defects in the "electrode type" electric heating bag 20 groups reached 84 times, and the total number of unqualified occurrences in the "electric wire type" electric heating bag in the same 20 groups of samples was 22 Times. Therefore, it should be boldly affirmed that the qualification rate of "electric wire type" electric heating bag has been greatly higher than that of "electrode type" electric heating bag, and from the results of our analysis, the "electrode type" electric heating bag is unqualified. The reason is mainly caused by the structure, and the reason why the "electric wire type" electric heating bag is unqualified is mainly caused by improper selection of raw materials. The "electrode type" electric heating bag also has the problem of improper selection of raw materials; A total of products. Therefore, as long as the targeted rectification can be.
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