New energy vehicle wiring harness Corrugated pipe, Corrugated pipe threading technology test method

Most of automotive wiring harness industry use corrugated pipe, which generally use flame retardant PA6 (nylon 6) material. Be used for automotive wiring harness, the corrugated pipe’s performance requirements are relatively high and need to comply with the relevant standards testing, including：Flame retardant test、Aging test、Thermal deformation test、Thermal aging test、Low temperature test、Corrugated pipe matching test、Slip wear test、Open-mouth recovery test、Chemical resistance test、Extend test、Load impact test、Vibration impact test. There is a certain standard for the enterprises to meet qualified automotive wire harness corrugated pipe. Only when complete the above test, the production of automotive wire harness corrugated pipe could be qualified products. Shenzhen SUNBOW Insulation Materials MFG. Co., Ltd. production of corrugated pipe is fully in line with these standards and successfully used in new high-voltage automotive wiring harness, electric control and drive motor!

 Test method as follows：

一. Appearance and size test

1.1 Appearance

Maintain a distance of 300-500mm and watch corrugated pipe how to product. And the bellows rigidity, flexibility and elasticity by hand test.

1.2 Inner diameter & Outer diameter

With each specification of the dedicated plug gauge on the corresponding corrugated pipe’s inner diameter test, measurement of three samples, the length of the sample size of the corresponding specifications of 12-15 times of the outer diameter. The measurement requirements for the plug gauge positive deviation deviations can not be passed, and negative deviations can be self-weight pass.

Outer diameter measure by 0.02mm accuracy slide caliper, measurement of three samples of 12 points, whichever is the average, should meet the requirements.

1.3 Wall thickness

Wall thickness measure by 0.02mm precision slide caliper. Three specimens were measured for radial wall thickness, with a sample length of 240 mm. Each cross section taken as four equally spaced position measurements, the measurement of 12 points, whichever is the average, should be consistent with the provisions.

二. Performance test

Unless specified, the test shall be carried out at an ambient temperature of 23 ± 2 ° C. 6 specimens shall be taken for each test. The length of the specimen shall be 240/480 mm. The test shall be carried out 7-10 days after production.

2.1 Flexibility and elasticity

2.1.1 Sample length of the opening. The specimen is bent around the round bar and the opening should be located on the outside of the bend. If the inner diameter of the sample is less than 10mm, the diameter of the round rod is 4 times the outer diameter of the sample. If the inner diameter of the sample is more than 10mm, the diameter of the round rod is twice that of the outer diameter of the sample.

Requirements: The sample can not be narrowed, the opening does not exceed 1.5mm.

2.1.2 The sample is not open, use the same way bending, require sample is not deformed, not concave.

2.1.3 From the open sample, through the opening remove the round rod, this time the opening should be gradually reduced to its original state.

2.2 Compression performance

A wire bundle having an outer diameter is 3/4 of the inner diameter of the sample inserted into a 240 mm long corrugated pipe, and let it be the test sample. It is placed on a flat plate, and the opening up, uniform application of a 12.755Kg of gravity in the sample, the time 1min, check the appearance of any deformation or cracks, unloading 15min, the determination of the rate of change of the sample’s outer diameter DT less than 10%.

2.3 Impact resistance performance

Samples test like 2.2 project, the opening placed down on a flat, from the height of 100mm from the sample at the free fall of a heavy object 750g, hit the sample, check the appearance of the sample without distortion or cracks.

2.4 Bending performance

2.4.1 Room temperature, the bellows bending test on the bending frame, requiring bending 100 times (about 50 times) case, shall not produce fracture, and in the state of bending 90 °, the plug gauge can be self-weight through.

2.5 Flame retardant performance test

2.5.1 Flame retardant performance of the material

Flame-retardant specimens should have the same material as the bellows. According to UL94 standard processing into the sample. According to UL94 standards, flame retardant performance test reached and exceeded V-2 level.

2.5.2 Flame retardant performance of the products

2.5.2.1 Routine testing

Samples test like 2.2 project, adjust the Bunsen burner blue flame height of 30 ± 2mm, the bellows placed horizontally on the flame, the combustion should be self-extinguishing within 30S. Three times in a row.

2.6 Electrical performance

2.6.1 Dielectric strength

Take three long 120mm corrugated pipe bent into U shape and fixed. The sample on the water, into the water length of 1000mm. Then the sample tube filled with water, the tube surface height consistent with the outside, the water temperature is 23 ± 5 ℃.

The two electrodes were inserted into the bellows and the water outside the tube respectively. After 24 hours, an AC voltage of 2000V and a frequency of 50 Hz was applied between the two electrodes, and the corrugated pipe were punctured within 15 seconds.

2.6.2 Insulation resistance

Test by surface resistance tester, require the product surface resistance ≥ 10M

2.7 Low temperature and high temperature performance

2.7.1 Take three in a length 240mm of open type corrugated pipe, the tube into a diameter of the pipe’s inner diameter 3/4 thick wire, from room temperature into the low temperature chamber, cooled to -25 ± 2 ℃, after 2h , removed the wire. Take it all around the metal tube (metal tube diameter of 4 times the outer diameter of the sample tube) requires removal within 2min from the inside of the package is completed, the specimen should be free of brittle, ripples shape are not deformed.

2.7.2 Samples test like 2.7.1 projects, placed in from room temperature to a high temperature chamber, heated to 90 ± 2 ℃ (PE material) or 20 ± 2 ℃ (PP material) for 2h, remove the test sample without deformed.

2.8 Oil resistance test

Take three in a length 480mm of seal type corrugated pipe, all around the metal tube (metal diameter of the sample tube diameter 4 times), immersed in a temperature of 20 ± 5 ℃ 90 gasoline, soak 48h, remove and place 1h. After checking, the sample should be closely and ripples shape are not deformed.

3.1 Storage

3.1.1 Avoid exposure, rain and mechanical damage.

3.1.2 The product should not be stored open-air, should be placed in the warehouse, stacking height should not exceed 2.5 meters.

3.1.3 Maintaining period: The corrugated pipe should be stored in the warehouse at normal temperature (23 ± 5 ℃) and normal humidity (50 ± 5%), and shall not be exposed to corrosive substances such as acids and alkalis and organic solvents. Within 6-9 months, Maintain its original technical performance.