How to test the fatigue resistance and heating life of silicone heating tubes

Firstly, understand the bending resistance and heating wire of the silicone heating tube device, and compare the values after repeated stretching and bending fatigue! Due to the need to wrap a fine carbon fiber thermal conductive wire during silicone extrusion, excluding other materials, the silicone heating tube and thermal conductive wire are not bonded, and forced packaging and extrusion will increase the looseness value of the inner hole!

1. ≤ 200 bending and stretching cycles: The silicone heating tube device has no significant change in thermal conductivity, and can maintain within the normal range of 10K Ω without significant resistance changes. The product can be used normally, and the plugs at both ends can still withstand 5KG of traction strength.

2. ≤ Bending and stretching 1000 times: The resistance value can still ensure that there is no significant fluctuation within the K Ω range of 100 times. At this time, when opening the surface of the silicone heating tube device, it can be found that the thermal wire and silicone packaging are loose. The tension can slightly affect the thermal wire, and observe the aperture between the thermal wire and silicone. Because the silicone heating tube device is bent, various thermal wires are loose, rather than changes in the silicone tube diameter! It has a certain impact on the silicone heating tube device, but it does not affect its use.

3. ≤ 10000 bending and stretching cycles: During continuous high-strength bending, four heat conducting wires become loose and in severe cases, break.

Method: When the current is connected, the resistance value can reach 30 Ω~70 Ω. If it fluctuates between 20~30 Ω, it indicates that the thermal conductivity wire is broken or loose, causing changes in resistance value. The higher the resistance value, the more thermal conductivity wires are broken or loose in the silicone heating tube device! The sudden decrease in heating life makes it unusable, which also increases the probability of loosening of the thermal conductive wire used in high-strength fatigue work.

Solution: After production, use a secondary vulcanization method to make the silicone vulcanization more completely shrink, giving the thermal conductive wire extra space in the silicone packaging to cope with fatigue. During bending, bending, and stretching, the heat conducting wire will not directly break or loosen at most.

The advantage of secondary sulfur addition is that the thermal conductive wire in the silicone heating tube device can be tightly wrapped and shrink at the same time. At this point, more thermal conductive wires should be reserved during the extrusion process. What does this mean? For example, if your product is 1.2 meters long with one heating tube in the middle. 18 meters, then the thermal conductivity wire should be slightly longer than the silicone tube because the thermal conductivity wire does not have stretching ability. Bending and stretching are necessary because silicone has stretching properties, and the thermal conductivity wire cannot be bent. Bending the thermal conductivity wire can only use the product's inherent hardness and bending force. Therefore, long-term use will cause the thermal conductivity wire of the silicone heating tube device to be unable to withstand greater stretching force for a long time, and it will break or loosen! If you have retained sufficient length of the thermal conductive wire, you can use the length of the product itself to handle the bending radius length caused by bending, so that you do not have to bear the force of bending and stretching, and can fully ensure the heating life.