5 Key Reliability Tests that PI Heater Must Perform

Polyimide (PI) flexible heaters are widely used in industries such as medical devices, aerospace, electronics, and battery heating due to their thin profile, fast thermal response, and high flexibility.

However, their reliability and performance are critical, especially in demanding applications. To ensure long-term stability and safety, PI flexible heaters must undergo a series of reliability tests. These tests evaluate electrical safety, insulation, thermal endurance, and mechanical strength. There are 5 points tests that PI heating film must do.

1. Dielectric Withstand (Voltage Test)

Purpose: To ensure the heater can safely withstand high voltage without breakdown or leakage.

• Default for PI heater films: AC 1200V, 5mA for 60 seconds without abnormality.
• For silicone or epoxy-coated heaters: AC 1500V, 5mA for 60 seconds without abnormality.

Even if the customer does not specify a voltage test, this is generally performed to confirm electrical safety and prevent potential short circuits or arcing during operation.

2. Insulation Resistance Test

To verify the electrical insulation between the conductor and the outer surface, PI flexible heater manufacturers always perform insulation resistance test to ensure there is no leakage current occurs. The testing condition is DC 1000V, impedance > 100MΩ.

High insulation resistance indicates excellent protection against electric shock and long-term operational reliability. This test is particularly important for heaters in sensitive electronics and medical devices.

3. Thermal Shock / Hot & Cold Cycling Test

This test is used to check how the heater performs under rapid temperature changes.

• Typical range: -25℃ to 125℃
• Cycle duration: 4 hours per cycle
• Condition: No abnormalities in the heater or conductor.

This test ensures the heater can tolerate extreme temperature fluctuations without material cracking, delamination, or resistance changes. If the customer provides specific requirements, testing parameters are adjusted accordingly.

4. Wire Pull / Lead Strength Test

• Purpose: To assess the mechanical strength of the connecting leads and ensure they can withstand handling or installation stress.
• Standard: Based on wire diameter and material, following a wire strength reference table.

A heater may fail if the leads break or detach during use, so this test verifies that the connection is secure and durable. Customer requirements may modify the standard pull force.

5. High-Temperature & High-Humidity Test

• Purpose: To evaluate the heater’s performance under prolonged exposure to heat and moisture.
• Standard: 60℃ / 95% RH, 240 hours
• Result: Heater should show no abnormality, such as delamination, corrosion, or resistance changes.

This test is essential for applications exposed to humid or harsh environmental conditions, ensuring the heater remains stable and functional over time.

Why These Tests Are Important?

Performing reliability tests is not just about meeting industry standards — it ensures:

• Safety: Prevents electrical failures or fire hazards.
• Durability: Confirms long-term performance under mechanical and environmental stress.
• Consistency: Guarantees uniform heating without hot spots or resistance drift.

Customer Confidence: Provides verification that the product meets or exceeds expected specifications.

Why Danyu Electronics is Your Trusted PI Heater Partner?

Reliability testing is a critical step in PI flexible heater manufacturing. Even though some tests are optional based on customer requests, standard tests such as dielectric withstand, insulation resistance, and high-temperature humidity tests help ensure safe, stable, and durable performance.

At Danyu electronics, we rigorously perform all necessary reliability tests on our PI heaters. From dielectric and insulation testing to thermal shock and wire pull strength, our engineers ensure each heater meets strict quality and safety standards before shipment.

If you need a custom PI flexible heater designed for high reliability and long-term operation, contact us at sales@best-heaters.com. Our team can guide you on testing options based on your specific application requirements.

FAQs

1. Is the dielectric withstand test required for all PI heaters?

No, it’s performed by default unless the customer specifies otherwise, with standard voltages of AC 1200V (PI) and AC 1500V (silicone/epoxy).

2. What is the purpose of insulation resistance testing?

It ensures no leakage current exists and confirms electrical insulation integrity between conductors and the heater surface.

3. How are thermal shock tests performed?

Heaters are cycled between -25℃ and 125℃ every 4 hours to simulate extreme temperature changes.

4. Why is the wire pull test necessary?

It verifies the mechanical strength of the leads and prevents failures during handling or installation.

5. What does high-temperature and humidity testing check?

It confirms the heater maintains performance under prolonged exposure to heat and moisture, simulating harsh operating environments.

标签：pi heater testing · polyimide flexible heater