DX8383 Hot wire testing machine
Introduction: The hot wire test is . The hot wire itself is actually a fixed specification resistance wire ring. During the test, it needs to be heated to the specified temperature by electricity, so that the top of the hot wire contacts the sample for the required time, and then its state can be observed and measured. The testing range depends on the specific test procedure.
Scope of application: The hot wire testing machine is mainly suitable for conducting fire hazard tests on electrical, electronic products, household appliances and their components, simulating the thermal stress caused by heat sources or ignition sources such as hot components or overload resistors in a short period of time. It is also suitable for solid electrical insulation materials or other solid combustible materials.
Compliant with standards: Designed and manufactured in accordance with the requirements of the "Glow Wire Test Method" in GB/T5169.10, GB/T5169.13-2006, IEC60695-2-10:2000, GB2099, VDE 0620, GB4706.1, UL817 standards.
Technical parameters:
1. Test chamber volume: 0.5M³, depth x width x height: 60x 95x 90cm
2. Boundary dimensions: depth x width x height: 61x 120x 105cm
3. Glowing wire: A 4.0mm diameter ring is made of nickel/chromium wire
4. Temperature measuring device: 0.5mm armored fine wire thermocouple, capable of withstanding high temperatures of 1050 ℃
5. Heating current: When the temperature is 960 ℃, the current is between 120~150A
6. Apply force to the test: 0.8~1.2N, and limit the pressing depth to at least 7mm
7. Timer: A timer for the duration of ignition (Ti) and flame extinguishing time (Te). Range: 0~99.99S
8. Glowing wire: 4mm±0.04mm Ni/Cr (80/20) specially designed standard ring, horizontally stationary;
9. Thermocouple: 0.5mm imported K-type thermocouple, armored sleeve heat-resistant to 1100 ℃;
10. Electric heating temperature of the hot wire: 500 ℃~960 ℃ (digital display can be preset), temperature fluctuation<3 ℃;
11. Pressure of the test sample to the hot wire test: 1.0N ± 0.1N (adjustable according to the actual situation);
12. Maximum penetration depth: 7mm ± 0.5mm (adjustable according to actual conditions);
13. Test sample movement speed: 10mm/s~25mm/s.
14. Severity level: The preferred values for the duration of the applied test flame (ta) are: 5s, 10s, 20s, 30s, 60s, 120-1s;
15. Flame height: The test flame height is 12mm;
16. Gas source: Butane gas (provided by the user).
17. Outer box material: Mirror stainless steel.
Test method: Heat the standard resistance wire ring to the specified temperature, and then make the hot wire and test sample contact the plug, socket, rubber, plastic and other products under the test conditions.
Corresponding test method for the hot wire combustion testing machine:
Burning wire flammability test method for finished products (IEC 60695-2-11:2000/GB/T 5169.11-2006)
Burning wire flammability test method for materials (IEC 60695-2-12:2000/GB/T 5169.12-2006)
Test method for ignition performance of materials using hot wire (IEC 60695-2-13:2000/GB/T 5169.13-2006)
Flammability index GWFI, GWFI - Glow wire flammability index
The maximum test temperature of a test sample with a specified thickness in three consecutive tests should meet one of the following conditions:
a) Within 30 seconds after removing the hot wire, the flame or heat of the test sample extinguishes, and the packaging paper placed under the test sample does not ignite;
b) The test sample did not ignite.
GWIT, GWIT - Glow wire ignition temperature
A temperature that is 25K higher than the highest temperature at the top of the hot wire that does not ignite a test sample of the specified thickness in three consecutive tests (30K higher between 900 ℃ and 960 ℃).
Sample requirements: The SGS Materials Laboratory has the following requirements for testing samples:
The sample should have a sufficiently large fixed size flat portion, and the test plane should be kept in a vertical position during testing.
The test samples can be made in several ways:
Compression molding, injection molding or casting, or cutting from finished parts such as sheet metal with a sufficiently large surface.
The dimensions of the flat part should be: length: ≥ 60mm, width (inside the fixture): ≥ 60mm
According to the requirements of this experiment, evaluating flammability usually requires a set of 10 test samples.
severity level
1. The Glow Wire Flammability Index (GWFI) should be selected from the following test temperatures
Test temperature/℃: 550/600/650/700/750/800/850/900/960
2. The ignition temperature of the hot wire (GWIT) should be selected from the following test temperatures
Test temperature/℃: 500/550/600/650/700/750/800/850/900/960
Evaluation of results:
1. Evaluation of Glow Wire Flammability Index (GWFI) Results
If the test sample does not ignite or meets the following two conditions, it is considered to have withstood this test
a) If the flame or ignition wire of the test sample extinguishes within 30 seconds after removing the ignition wire
b) The packaging paper did not ignite
If one or both of the above conditions are not met, choose a lower test temperature and repeat the test with a new test sample.
If both of the above conditions are met simultaneously, select a higher test temperature and repeat the test with a new test sample.
The test should be repeated at the highest test temperature when the test sample meets conditions a) and b).
To determine the maximum test temperature that satisfies conditions a) and b) for three consecutive tests in GWFI.
2. Evaluation of Glowing Wire Igniting Temperature (GWIT) Results
The ignition temperature of the test sample during the application of the hot wire should be determined, and the test temperature that is 25K (30K between 900 ℃ and 960 ℃) higher than the highest temperature at the top of the hot wire that did not ignite the test sample in three consecutive tests should be recorded as GWIT
Precautions for using the hot wire testing machine:
1. The user of the hot wire testing machine must maintain a stable power supply, otherwise excessive voltage fluctuations can affect temperature changes.
2. Thermocouples are only used for temperature calibration in experiments. After calibration, mark them on the ammeter for the next test. When the temperature drops to room temperature, carefully remove the thermocouple from the hot wire and start the experiment.
3. The hot wire should not work for a long time at high temperatures to avoid shortening the service life of the thermocouple. After each use, the current should be reduced in a timely manner and the power should be cut off.
4. After each test, the combustion chamber should be cleaned with power off, and care should be taken not to collide with thermocouples and hot wires.
5. After the experiment is completed, users can use the exhaust fan to exhaust the exhaust gas generated during combustion, but do not turn on the fan during the experiment to avoid affecting the test results.
6. If maintenance is required, especially for the replacement of the hot wire, attention should be paid to retightening the screws that have been tampered with, otherwise poor contact will affect the current circuit and generate high temperature at the interface. After replacing parts, users should tighten all screws.
7. The hot wire testing machine has an over temperature protection function. When the set temperature is reached, the heating circuit will be automatically disconnected. Therefore, the preset temperature cannot be lower than the normal working temperature, otherwise it cannot work normally
Experimental specifications:
1. Purpose: To standardize the operation, maintenance, and upkeep of the hot wire tester and ensure its normal operation.
2. Scope: Suitable for flame retardant testing of plastic parts for various products
3. Reference standard: According to the test requirements of relevant clauses in the GB/T5169.10-2008 "Basic Test Methods for Glowing Wire/Glowing Wire - Glowing Wire Devices and General Test Methods" standard;
Instrument maintenance and precautions:
1. Every week, maintenance and management of instruments, as well as operational checks of related adjustment key functions, must be carried out, and records must be kept.
2. The tester must have a stable power supply, otherwise voltage fluctuations can affect temperature changes.
3. When conducting experiments. We should adopt a method of slowly increasing and decreasing temperature. When starting to apply current, we should take it slowly and not increase the temperature too high all at once! This way, the usage time will be longer, and the current should be gradually increased. Do not increase it to 90 or higher.Increase 30-40A at once is basically stable. When adding and cooling, also slowly reduce the current and do not drop to zero all at once. Rapid thermal expansion and contraction can cause damage to U-shaped heating wires and glow wire thermocouples. These damages are irreparable. Once damaged, it needs to be repurchased
4. The hot wire should not work for a long time at high temperatures to avoid shortening the service life of the thermocouple. After each use, the current should be reduced in a timely manner and the power should be cut off.
5. After each experiment, the combustion chamber should be cleaned under power-off conditions, and attention should be paid not to touch the thermal couple and the burning wire.
6. If maintenance is required, especially for replacing the hot wire, it is important to tighten the screws that have been tampered with, otherwise poor contact will affect the current circuit and generate high interface temperatures. After replacing parts, users should tighten all screws.
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