What Are Flexible Heaters? Polymide vs. Silicone

Blog / What Are Flexible Heaters? Polymide vs. Silicone

Sept 19, 2025

Introduction

Flexible heaters are thin, lightweight, and customizable heating elements used for precise temperature control in compact or complex spaces. These heaters are designed to convert electrical energy into heat through resistance heating. This process involves electricity flowing through a resistive element embedded within the flexible substrate, which generates heat as it meets resistance. The materials used are highly effective at conducting electricity and distributing heat evenly.

Based on their insulating materials, there are two main types of flexible heaters: Polyimide Flexible Heaters and Silicone Rubber Heaters. Each type offers unique properties suitable for various industrial and commercial heating needs.

Difference Between Polyimide Flexible Heaters and Silicone Rubber Heaters

Specification	PI Flexible Heaters	Silicone Flexible Heaters
Substrate Thickness	0.09–0.27 mm	1.0–2.0 mm (including silicone layer)
Light Transmittance	60.2% (for 50μm PI film) 70.6% (for 25μm PI film)	0%
Operating Temperature Range	-40°C to 260°C (recommended long-term use: below 150°C)	-40°C to 300°C (recommended long-term use: below 200°C)
Dielectric Strength	1–380 VAC / 2000 VDC1 min test leakage current ≤ 1 mA	1–380 VAC / 2500 VDC1 min test leakage current ≤ 1 mA
Insulation Resistance	≥100 MΩ @ DC 1000V	≥500 MΩ @ DC 1500V
Max. Power Density	1.0 W/cm²	2.0 W/cm²
Thermal Conductivity	0.2–0.35 W/(m·K)	1.0–1.5 W/(m·K)
Mechanical Compressive Strength	≤ 50 kg/cm²	≥ 200 kg/cm² (typically up to 350 kg/cm²)
Lead Wire Pull Strength	≥ 100 N	≥ 100 N
Service Life	Up to 5 years	Up to 5 years
Solder Joint Pull Strength	≥ 40 N	≥ 40 N

Structure and Material of Flexible Heater

A typical flexible heater consists of 2 kinds of layers: insulation (substrate) and etched metal foil.

1. Insulation

Polyimide (PI) is an organic material known for its high dielectric capability, providing excellent heat resistance and electrical isolation. It functions effectively in a wide temperature range, from -200°C to 300°C. As an insulator, it offers strong mechanical strength and high insulation performance, ensuring electricity flows efficiently through the metal foil.

Silicone Rubber has high-temperature resistance, moisture resistance, and electrical insulation. It can operate between -50°C and 250°C and provides protection against harsh conditions. It maintains resilience and stability across electrical, thermal, mechanical, and environmental properties, even under extreme temperatures.

2. Etched Metal Foil

The resistive core of flexible heaters is usually copper, stainless steel, or iron-chromium-aluminum alloy, which is laminated between layers of flexible insulation by high-temperature and high-pressure. These metals all possess relatively high resistivity and favorable electrical-to-thermal conversion efficiency, enabling our flexible heaters to generate heat rapidly and consistently.

Features of Flexible Heater

• Customizable & Flexible: A flexible heater can be custom-tailored in size, shape, wattage, and temperature to meet specific application needs. Its flexible design allows it to bend and conform to curved or irregular surfaces.

• Ultra-Thin & Lightweight: With minimal weight or bulk, it fits easiliy into compact or limited spaces without compromising performance.

• Energy Efficiency: Flexible heaters are highly efficient in converting electricity into heat. Compared to traditional heating methods, they offer lower energy consumption and reduced operational costs, while delivering consistent, high performance.

• Reliable & Consistent: With no moving parts and the inherent durability of design, it offers long-lasting and reliable performance, maintaining uniform heat output even in demanding environments.

• Durability: It is engineered to withstand vibration, moisture, chemicals, and mechanical stress for a long service life. Polyimide heaters can withstand temperatures from -40°C to 260°C, while silicon rubber heaters can operate from -40°C to 300°C.

• Rapid & Uniform Heating: With high thermal conductivity, it has a fast heat-up time, typically seconds to minutes, and offers uniform heat distribution across the surface.

• Simple Installation: Flexible design and adhesive backing (e.g., 3M™) enable easy mounting on flat or curved surfaces.

Application Scenario

From surgical tools in the operating room to wearable electronics close to the skin, flexible heaters deliver reliable performance across a wide range of applications. There are some common uses below.

1. PI Heating Films Excel In:

• Aerospace (dashboards, avionics heating, fuel line heating, sensor protection, optical system, and de-icing system)

• Automotive (mirror defogging, thermal control of battery packs, and wiper blades)

• Medical devices (diagnostic instruments, lab equipment, sample trays, reagent bottles, IV tube warmers, blood warmers, incubators, medical imaging systemsand CPAP machines)

• Consumer electronics (battery warming in cameras/phones/laptops, heated beauty devices, handwarmers)

2. Silicone Rubber Heaters Ideal For:

• Industrial Equipment (temperature control of machinery components, platen heating, process tank warming, pump & valve freeze protection, conveyor belt de-icing)

• Energy Systems (solar panel snow melting, wind turbine blade de-icing, energy storage thermal management, fuel cell heating)

• Marine and Boating (boat hull de-icing, engine block heaters, bilge pump freeze protection, marine electronics thermal management)

• Transportation: (pipe freeze protection, engine component pre-heating, fluid reservoir warming, thermal control of battery packs)

Why Choose JLCPCB Flexible Heater?

• One-Stop heating Customization: JLCPCB Flexible Heater simplifies the process with a custom heater solution, including free circuit design support and expert heating solution consultations, assisting you in designing faster and validating prototypes sooner.

• Competitive Price: Market quotes for custom heaters are often unreasonably high. JLCPCB Flexible Heaters offers competitive price, typically reducing costs by over 90% under the same area conditions.

• Rapid Prototyping: No MOQ limits, shipping as fast as 3 business days, JLCPCB Flexible Heater gets your concepts to reality faster and boosts your time-to-market.

• Instant Online Quotes: Securely upload your design file to our online platform for an instant quote that updates instantly based on selected materials and custom specifications.

• Precision & Flexibility: JLCPCB Flexible Heater provides customizable flexible heaters with 0.5-1.0mm dimensional tolerance and ±5% resistance value tolerance, enabling precise control over power, size, and shape, including profiled heating.

• Superb Appearance Quality: Upon request, JLCPCB Flexible Heater performs 100% visual inspection with strict appearance standards. Even minor defects like wrinkles, light scratches, or misalignments will be rejected and re-manufactured to ensure perfect appearance in every piece.

• 100% Resistance Testing: If selected, JLCPCB Flexible Heater will take 100% resistance testing of all heating films in your batch. Each piece will be individually measured to ensure compliance with your design specifications.

How to Make a Flexible Heater at JLCPCB Flexible Heater

1. Visit the JLCPCB Flexible Heaters Website

2. Configure Specifications

Choose your flexible heater properties, such as:

⦁ Material and Dimensions

⦁ Design Parameters (voltage, power/resistance, temperature)

⦁ Adhesive Backing

⦁ Lead Wire

Notice: It is recommended to upload Gerber files (in ZIP or RAR format) or CAD drawings (in DXF or DWG format). The maximum file size is 100MB.

3. Place the Order

Once all parameters are confirmed, proceed to checkout. Choose a shipping method based on your delivery timeline and budget.

Notice: Before production starts, our engineers will reprocess and manually confirm the production files. The lead time will be recalculated based on this confirmation.

4. Get Started

Submit files and specifications (voltage, wattage, dimensions, and so on) via the JLCPCB Flexible Heaters website initiate your order.

Conclusion

Flexible heaters deliver precision thermal management where traditional solutions fall short. Choosing the right solution, whether PI flexible heaters or silicone rubber heaters, hinges on your operational environment, thermal requirements, and mechanical constraints. If you have any questions about flexible heaters, such as specifications, material selection, or design challenges, please contact the JLCPCB Flexible Heaters support team.