Electric blankets, heated pads and flexible heating appliances are repeatedly folded, compressed, rolled and locally stretched during use. They must also withstand operating voltage, temperature rise, moisture and abnormal conditions. A dielectric-strength test alone cannot evaluate the complete risk. A laboratory should combine mechanical endurance, heating-wire flexing, electrical strength, ignition and moisture-resistance equipment according to GB 4706.8, IEC 60335-2-17 and the applicable product specification.

1. Mechanical Strength Test Module

The mechanical strength tester simulates pressure, rolling and bending caused by long-term use. A typical machine uses rollers, loading cylinders, a sample support platform, drive system and cycle counter. The sample must be laid flat and secured without creating non-standard folds. The system should support the largest blanket size and provide repeatable force and motion.

2. Bending and Heating-Wire Flexing

Bending testers and heating-wire flexing machines evaluate conductors, heating wires and connection areas under repeated movement. The test program should define bending radius, travel, speed, suspended load and cycle count. Continuity monitoring is recommended so that the machine stops and records the failure cycle when an open circuit, short circuit or abnormal condition occurs.

3. Dielectric Strength and Hipot Testing

A production or laboratory hipot system may use upper and lower conductive tables to press the complete appliance and apply AC or DC test voltage. The installation should include guarding, dual-hand start or door interlock, leakage-current measurement and audible/visual alarm. For production inspection, sample loading time, test cycle and reject isolation are important design factors.

4. Flammability and Abnormal Tests

• Spark ignition equipment simulates internal arcing and evaluates overheating or ignition risk;
• Drum-drop equipment checks controllers, plugs and accessories after repeated mechanical impact;
• Temperature-rise and abnormal-operation tests monitor heating zones, controllers and connections;
• Flexible fabric leakage equipment evaluates moisture-resistant covers and flexible structures.

5. Recommended Test Sequence

1. Condition the sample and record dimensions, appearance, resistance and insulation condition;
2. Perform mechanical strength, bending or wire-flexing endurance;
3. Inspect continuity, local damage and heating-wire displacement at defined stages;
4. Carry out dielectric-strength, leakage-current and insulation checks after mechanical testing;
5. Perform temperature-rise, abnormal-operation, ignition and moisture-resistance tests as required;
6. Compile cycle count, failure location, temperature and electrical data in the final report.

6. Equipment Selection

Specify maximum sample size, rated power, test voltage, loading method, target cycles and number of stations. Therapy pads and special-shape products may require custom rollers and sample fixtures. Safety functions should include emergency stop, door interlock, overload, wire-break and leakage protection.

7. Maintenance and Quality Control

Drive components, bearings, roller dimensions and applied force require periodic inspection. High-voltage instruments must be calibrated for voltage and leakage current, and temperature channels require traceable calibration. LSKFT can provide combined mechanical strength, bending, flexing, hipot, spark ignition and moisture-leakage equipment for electric blankets, heated pads and therapy pads.