How to detect and maintain the insulation of mold heating tubes?

1. Methods for testing the insulation of mold heating tubes

Insulation resistance test

Using an insulation resistance tester is the most common method. Before testing, it is necessary to ensure that the heating tube is in a power-off state and the surface is clean and dry, because moisture and dirt may affect the test results. Connect the two test wires of the tester to the wiring terminals of the heating tube and the shell of the heating tube respectively. For mold heating tubes with lower rated voltages (such as 220V or 380V), the insulation resistance should generally not be less than 1MΩ. If the insulation resistance value is too low, it indicates that there may be problems with the insulation performance of the heating tube.

For example, in the detection of the heating tube of a small injection mold, when the ambient temperature is 25℃ and the humidity is 50%, a 500V insulation resistance tester is used for detection. The normal insulation resistance value of the heating tube reaches 2MΩ, which meets the requirements for safe use.

Mold heating tube

Withstand voltage test

This is a more stringent detection method. Through the withstand voltage tester, a test voltage higher than its rated voltage is applied to the heating tube for a period of time (usually 1-5 minutes). For example, for a heating tube with a rated voltage of 220V, a test voltage of 1000V-1500V may be applied. If the heating tube does not break down or flash over during the withstand voltage test, it means that its insulation performance is good. However, the withstand voltage test is destructive to a certain extent and may damage the heating tube that already has potential insulation problems, so it is generally used when inspecting new heating tubes or heating tubes suspected of having serious insulation problems.

2. Measures to maintain the insulation of mold heating tubes

Prevent moisture

The humidity of the environment where the mold heating tube is located should be kept as low as possible. If the humidity in the working environment is high, you can consider sealing and protecting the heating tube or installing dehumidification equipment. For example, in some mold workshops in coastal areas, dehumidifiers are used to control the humidity in the workshop below 60% during the rainy season to reduce the possibility of moisture in the heating tube.

Avoid mechanical damage

During installation and use, prevent the outer shell of the heating tube from being scratched or collided. Because once the outer shell is damaged, the internal insulation structure may be damaged. For example, when moving the mold, pay attention to protecting the heating tube to avoid contact with other hard objects.

Regular cleaning

Dust, oil and other impurities on the surface of the heating tube may reduce its insulation performance. It is necessary to clean the surface of the heating tube regularly with a clean cloth or appropriate detergent. However, during the cleaning process, avoid the detergent from entering the wiring terminals and other parts of the heating tube to avoid short circuits.

Reasonable use and selection

Ensure that the working voltage, current and other parameters of the heating tube are within the rated range. If it is overloaded for a long time, the aging of the insulation material inside the heating tube may be accelerated. At the same time, when selecting, choose a heating tube product with reliable quality and good insulation performance. For example, choose a heating tube with a high-quality magnesium oxide powder insulation layer. This material has good insulation performance and thermal conductivity, which can effectively improve the insulation and heating effect of the heating tube.