Thick Film Heaters

Thick Film Heaters are efficient heating elements that use advanced thick film technology to print dielectric, resistive, conductive, and insulating materials onto flexible PI, ceramic, or stainless steel substrates, with a manufacturing process that involves precise material mixing, layer-by-layer printing, high-temperature sintering, and laser trimming to optimize heater design and performance, ensuring excellent resistance to high temperatures, wear, and corrosion for stable long-term operation in harsh environments.

Thick Film Heaters generate heat by passing an electric current through a resistive layer, utilizing the resistive heating effect to convert electrical energy into heat. The uniform thickness and stable materials of the resistive layer ensure even heat distribution, maintaining consistent heating performance. Additionally, thick film technology allows for precise customization of the heating areas, enabling adjustments to power and shape based on specific application requirements, thus providing accurate temperature control.

Thick Film Heaters are widely used across industries, including automotive, aerospace, electronics, medical devices, and renewable energy. They are commonly found in temperature control systems, seat heaters, sensors, thermal management systems, and solar water heaters. In automotive applications, they are used for seat heating and defrosting; in medical devices, such as incubators and blood warmers; and in electronics, for LCD backlighting and heating pads. Known for their reliability and durability, thick film heaters meet the high-efficiency heating needs of various applications, making them vital components in many fields.

Substrate Features of Thick Film Heaters :

Thick Film Heaters rely on a carefully selected substrate that is crucial for optimal performance, durability, and reliability. The choice of substrate depends on the specific application requirements and desired heater characteristics. Key features of substrates used in Thick Film Heaters include:

1, Materials: The most commonly used materials for substrates in Thick Film Heaters include Ceramic, Flexible Base (Polyimide or PET), Mica, and Stainless Steel. Each material has its unique characteristics and is chosen based on the specific application requirements.

2, Thickness: The thickness of the substrate determines the overall size and thermal mass of the heater. Thicker substrates offer higher mechanical strength but require more energy to heat up, while thinner substrates heat up faster but may be less durable.

3, Thermal Conductivity: The thermal conductivity of the substrate affects the heat transfer rate and the temperature distribution across the heating element. A substrate with high thermal conductivity ensures efficient heat transfer and uniform heating.

4, Electrical Properties: The substrate's electrical properties, such as dielectric constant and resistivity, influence the overall performance of the Thick Film Heater. These properties must be carefully selected to ensure proper functioning of the heater.

5, Surface Finish: The surface finish of the substrate is critical for ensuring optimal adhesion of the printed layers. It must be smooth and free of any contaminants or defects.

Thick Film Heaters developed and manufactured by Panda PCB offers several advantages, including high power density, compact size, high pressure resistance, no power attenuation, fast thermal response, not easy to scale, a heat conversion rate of up to 96%, no risk of open fire, excellent safety, and long service life. It is an efficient heating solution with high energy efficiency and targeted, homogeneous heat distribution.

Please refer to Thick Film Technology for more informations.

Main Types of Thick Film Heaters :

1, Ceramic-Thick Film Heaters :

Ceramic Thick Film Heaters are used when high temperatures are required, fast responses or temperature gradients are needed or products need to be heated in certain areas in a targeted way.

Ceramic Thick Film Heaters typical operating temperatures range from 300°C to 700°C (550°F – 1300°F) producing infrared wavelengths ideal for caramelization of breads, warming and heating of foods, curing of coatings, and softening or welding of plastics.

Ceramic Thick Film Heaters are capable of transferring up to 92% of their input as radiant energy, maximum efficiency is reached when the emitted wavelength and the absorption spectrum of the material to be heated are optimized, Which is with High compression strength, hardness and wear resistance, It can facilitate high heat resistance and high thermal conductivity applications.

Ceramic (Alumina or Aluminum Nitride): Ceramic substrates provide good thermal conductivity, electrical insulation, and high-temperature resistance. They are suitable for applications that require efficient heat transfer and high operating temperatures.

Rather than radiating heat into objects in its path, Ceramic Thick Film Heater absorbs it through direct contact with them.The heat in radiant heaters does not spread uniformly throughout the space, as it does with convection heaters, but it lasts for a longer period because it is retained within objects rather than in the air.

2, Stainless Steel-Thick Film Heaters :

Stainless Steel Thick Film Heaters are suitable for applications with surface loads up to 50 W/cm², and appropriate heat dissipation by water or another medium is required. The heater is capable for applications that need high temperatures of up to 840 °F (450 °C), Also applied to complex shapes to generate targeted heat.

Stainless Steel Thick Film Heaters normally used insulated chrome steel or chrome nickel steel or stainless steel as the base material. The high mechanical stability allows molding of the metal base as well as using insert technology for combination with plastic materials.

The structure of appliances with stainless steel thick film heaters will be relatively easier, more compact and exquisite, Temperature rise faster and more stable with lower heat capacity, also more moldability and mechanical stability.

Stainless Steel (SUS304 or SUS430): Stainless steel substrates offer excellent corrosion resistance and high mechanical strength. They are commonly used in applications where durability and resistance to harsh environments are important.

The main thing to stress here is that dielectric layer separates between the stainless steel substrate and the printed conductor traces, The dielectric materials are generally using enamel, polymers, or epoxies resin based all to be not conductive.

3, Flexible Heaters (Polyimide Heater and Polyester Heater) :

Flexible Heater is a thin and lightweight heating solution that utilizes an organic polyimide, silicone, and polyester (PET) film. It is specifically designed to cater to precise heating requirements within a temperature range of -319 to 392°F (-195 to 200°C). This heater offers exceptional tensile strength, tear resistance, and dimensional stability.

There are three types of Flexible Heaters available: Polyimide Heaters (PI Heaters), Polyester Heaters (PET Heaters), and Silicone Heaters. The majority of these flexible heaters are constructed with polyimide material, which enhances their flexibility for curved surfaces and provides resistance against chemicals. The thin profile of these heaters makes them particularly suitable for applications in confined spaces. They are commonly utilized in various settings such as hot plates, airplanes, storage tanks, beakers, trays, drying chambers, and more.

Flexible Base (PI or PET): Flexible base materials like Polyimide or PET allow for bending and conforming to curved surfaces. They are often used in applications where flexibility and thinness are required, such as in wearable devices or curved heating surfaces.

Flexible Heaters can introduce new design versatility to creatively solve a variety of thermal management challenges from more consistent environment stabilization to faster thermal cycling. With PANDA-PCB's Flexible Heaters you can use your imagination to apply heat to the most complex shapes conceivable, and do it with efficiency, dependability and value.

4, Mica Heaters :

Mica Heater is a type of heating element that is used to heat a wide range of industrial and commercial applications. It is composed of thin sheets of mica, which are laminated with resistive wire. Mica heaters operate on the principle of Joule heating, where an electrical current is passed through the resistive wire, generating heat which is then transferred to the object being heated.

Mica Heater is a specific type of Mica heater that features a thicker layer of resistive material applied to the Mica substrate. In contrast to thin film Mica heaters, which have a thin layer of resistive wire, thick film Mica heaters are designed to handle higher power densities and provide more uniform heat distribution.

Mica heaters provide an efficient and robust heating solution for industrial and commercial applications that demand higher power output and uniform heat distribution.

Mica Substrates offer excellent electrical insulation, high-temperature resistance, and good thermal conductivity. They are often used in applications that require high power density, such as in industrial heating or high-temperature furnaces. Mica substrates can also provide good mechanical stability and resistance to thermal shock, making them suitable for harsh environments. However, mica substrates may not be suitable for applications that require flexibility or conformability.

Mica Heaters come in various shapes and sizes, including flat, rectangular, round, and cylindrical. They can be custom-designed to fit specific applications, providing a highly efficient heating solution that is capable of meeting the most demanding industrial requirements.

Appilcations of Thick Film Heaters :

1, Industrial :
Electronic enclosures, plastic fabrications, water heating, packaging lines, and hot plates.
2, Food and Beverage Equipments :
Hot food displays, warming trays, storage warming, holding cabinets, brewing temperature maintenance, and portable food delivery.
3, Aviation and Transportation :
Instrumentation, oil and battery heating, personal comfort, deicers, over the road truck and railcar freeze protection.
4, Food Service :
Warming holding cabinets, fryer systems, display shelves, prep stations,grilling platters, heated dishware, and appliances.

5, Automotive :
Cabinet comfort heating, battery warming, fuel cell temperature maintenance, motor heating, mirror defogging, steering wheel and seats heating, door handle de-freezing, and coolant heaters.
6, Medical and Life Sciences :
Instrument warming, MRI equipment, temperature therapy, dialysis, CPAP, surgical devices, vessel sealer, DNA analysis and testing, blood diagnostics, blood and fluid warming, and sterilization.

7, Analytical Instruments and Research Institutions :
Imaging equipment, thermal analysis, chromatography, spectrometers, separation and membrane sciences.
8, Semiconductor :
High temperature burn-in and testing equipment, water heating, wafer chuck heaters.
9, Security :
Explosives detection, alcohol detection, chemical detection, and cameras lens defogging.
10, Printing :
Thermal printers, 3D-Printers, card printers, laser printers, commercial and industrial printers.
11, Health and Beauty Appliances :
Skin spa and facial steamer, heating pads and blankets, personal hair styling and drying tools, heating body and foot massager, and sauna belts.

Main Advantages of Thick Film Heaters :

1, Without Electrical Complication :
The printing patterns can reduce potential electrical inductance and capacitance inherent in wound resistance wires.
2, High Operating Temperature :
Ceramic-Thick Film Heaters have maximum operating temperature up to 1800°F.
3, Corrosion Resistant :
Ceramic Thick Film Heaters have excellent corrosion resistance and perform well under corrosive conditions where acid and alkali solutions exist. For Aluminum-Thick Film Heaters, after forming a layer of oxidation by gaseous acids present in the air, which serves a corrosion-resistant layer.
4, Low Profile :
The most distinguishing character of Thick Film Heater is its low profile and can made with a small dimensions, the thick film heater minimize the space requirements and is ideally suitable for thermal coupling to flat heat sinks, printed circuit boards and bulk heads etc.

5, Long Life :
Service life of Thick Film Heaters can be very long if the application conditions can be met according to instruction of operations. Thick film heaters tend to last longer if the temperature is kept below its designed maximum temperature rating.
6, Heating Patterns :
Thick Film Heaters are made with screen printing process for heating traces, which can be tailored to applications to deliver even heat for thermal uniformity across a surface, or different power densities in different areas.

7, Light Weight :
The thick film heater is thin and light weight, and excellent for applications which need rapid heating and uniform temperature. The low mass also lowers energy consumption and boost performances.
8, Low Thermal Mass or Heat Capacity :
The low thermal mass is ideal for rapid thermal response or fast temperature cycling. which Having a low heat capacity, the temperature can be increased quickly by using low amount of energy.
9, Maximum Heat Transfer :
Due to the direct surface contact, a Thick Film Heater ensures efficient heat transfer via conduction through thermally stable substrates and precise resistance trace patterns.
10, Odd Form Factors :
Unlimited unusual heater shapes and geometry to fit target areas for unique heating patterns. The intention is to fit custom profile or area.

Manufacturing Processes of Thick Film Heaters :

● Substrate Selection: Thick Film Heaters can be made on various substrates, including Ceramic Core Alumina (Al2O3), Ceramic Core Aluminum Nitride (AlN), Thick Film Aluminum (Al), and Thick Film Stainless Steel. The choice of substrate can determine the heater's nomenclature and suitability for different applications.

● Preparation of the Substrate: The process typically begins with the preparation of a stainless steel substrate. It must be thoroughly cleaned to remove any contaminants such as fingerprints, dust, oil stains, and grease. Special care is taken to handle the substrate to avoid recontamination, and gloves are often worn during subsequent handling to maintain cleanliness.

● Screen Printing: A common method for fabricating Thick Film Heaters is screen printing. This involves using a mesh screen with a patterned stencil to transfer a paste (which will form the insulating medium or conductor) onto the substrate. The screen is lowered onto the substrate, ink is pushed through the mesh onto the substrate, and then the screen is lifted away.

● Printing Insulating Medium: An insulating medium is screen printed onto the stainless steel substrate. It's recommended to use a specific mesh size for the screen and to control the sintered thickness of each layer to ensure sufficient insulation. The insulating medium slurry is dried and sintered at specific temperatures to achieve the desired thickness and properties.

● Printing Conductor: Once the insulating layer is in place, conductive traces are screen printed onto the insulating medium. The conductive paste contains metal particles that will form the heating element. The same drying and sintering process is used as for the insulating medium.

● Drying and Curing: After screen printing, the layers are dried to remove the solvents from the paste and then cured or sintered at high temperatures to harden the material and establish the desired electrical properties.

● Control Over Resistance and Watt Density: The manufacturing process of Thick Film Heater allows for a high degree of control over the heater's resistance, wattage, watt density, and uniformity. This is achieved by carefully controlling the thickness and width of the printed layers.

Design Considerations for Thick Film Heaters :

Designing Thick Film Heaters requires a meticulous approach to ensure optimal performance, efficiency, and reliability. Here are some key considerations to keep in mind when designing Thick Film Heaters:

1, Substrate Selection: Choosing the appropriate substrate material is essential for thermal stability and compatibility with the application environment. Common substrate materials include alumina (Al2O3) , aluminum nitride (AlN) and stainless steel, known for their excellent thermal conductivity and mechanical strength.

2, Thermal Design: Effective thermal management is critical to prevent overheating and ensure uniform temperature distribution across the heater surface. Factors such as substrate thickness, heater layout, and heat sink integration must be carefully considered to achieve desired thermal performance.

3, Material Selection: Selecting high-quality thick film materials is vital for achieving desired electrical and thermal properties. Materials such as resistive pastes, dielectric layers, and protective coatings must be chosen based on their temperature stability, electrical conductivity, and compatibility with the substrate material.

4, Heater Configuration: The design of the heater element, including its size, shape, and pattern, directly influences its heating characteristics and efficiency. Optimizing the heater configuration involves balancing factors such as heating uniformity, power density, and space constraints within the application.

5, Electrical Considerations: Proper electrical design is essential to ensure safe and reliable operation of the thick film heater. This includes selecting appropriate voltage ratings, current-carrying capacity, and insulation techniques to minimize the risk of electrical breakdown and ensure compliance with regulatory standards.

6, Environmental Compatibility: Thick Film Heaters may be subjected to various environmental conditions, including moisture, corrosive gases, and mechanical stress. Design considerations should include measures to enhance the heater's resistance to environmental factors, such as encapsulation, conformal coatings, and protective housings.

7, Manufacturability and Cost: Designing for manufacturability involves optimizing the manufacturing process to achieve high yield rates and minimize production costs. Considerations such as material utilization, process efficiency, and automation can significantly impact the overall cost-effectiveness of Thick Film Heater production.

Why Deed to Customize Thick Film Heaters ?

Custom Thick Film Heaters is essential for a variety of reasons that cater to the specific needs of different applications. Here's why customization is key for thick film heaters:

● Precision and Accuracy: Custom Thick Film Heaters can be designed to meet exact specifications regarding power output, temperature range, and response time, ensuring they perform accurately for their intended use.

● Application-Specific Requirements: Different applications may require heaters with unique shapes, sizes, or configurations. Customization allows for the creation of heaters that fit perfectly into the application's design, whether it's for a small device or a large industrial process.

● Material Compatibility: By customizing the material used in the thick film heater, it's possible to ensure compatibility with the surrounding components and the environment in which the heater will operate, enhancing the longevity and reliability of the system.

● Efficiency and Energy Use: Customized thick film heaters can be optimized for energy efficiency, reducing power consumption and operating costs without compromising performance.

● Reliability and Durability: Custom heaters are often built to be more robust and reliable, with the ability to withstand harsh conditions or specific operational demands that off-the-shelf products might not be able to manage.

● Thermal Performance: Tailoring the design of the thick film heater allows for precise control over thermal performance characteristics, such as uniformity of heat distribution and heat-up times, which are critical in many applications.

● Integration with Control Systems: Custom Thick Film Heaters can be integrated with control systems for precise temperature management, which is particularly important in applications like medical devices or precision manufacturing processes.

● Regulatory Compliance: In certain industries, products must meet specific regulatory standards. Custom Thick Film Heaters can be designed to comply with these standards, ensuring the end product meets all legal requirements.

● Cost-Effectiveness: While there may be an initial investment in customization, it can lead to cost savings over time by reducing the need for modifications, replacements, and optimizing manufacturing processes.

● Innovation: Customization enables the development of innovative solutions that may not be possible with standard products, allowing companies to stay ahead in a competitive market.

Custom Thick Film Heaters provides a tailored approach to thermal management, ensuring that the heaters meet the unique demands of specific applications and providing a competitive edge through enhanced performance, reliability, and efficiency.

Why Choose PANDA PCB For Thick Film Heaters ?

PANDA PCB Group - Thick Film Solution, a company dedicated to thick film heating elements, boasts a solid 20-years track record in product research, development, and manufacturing. Choose PANDA PCB for your thick film heaters needs and feel the difference that a dedicated and experienced partner can bring. Trust in our expertise, innovation, quality, and customer-centric approach.

● Unmatched Quality: At PANDA PCB, we prioritize quality above all else. Our Thick Film Heaters are crafted using high-grade materials, ensuring exceptional performance, reliability, and durability. With our heaters, you can trust that your heating applications will operate flawlessly.

● Tailored to Your Needs: We understand that every heating requirement is unique. That's why PANDA PCB offers extensive customization options. From size and shape to voltage requirements and power outputs, we provide flexible solutions that precisely meet your specific needs. Our expert team will work closely with you to deliver a customized heater that perfectly fits your application.

● Cutting-Edge Manufacturing: With PANDA PCB, you benefit from our advanced manufacturing technology. Our state-of-the-art facilities employ innovative techniques like screen printing and laser trimming to ensure precise and accurate production.

● Competitive Pricing: We believe that superior heating solutions shouldn't break the bank. PANDA PCB offers highly competitive pricing without compromising on quality. Our cost-effective solutions make it easier for businesses of all sizes to access top-quality thick film heaters within their budget.

● Rigorous Quality Control: Your satisfaction and peace of mind are our priority. PANDA PCB implements stringent quality control measures throughout the manufacturing process. Each thick film heater undergoes rigorous testing to guarantee its reliability and performance.

● Exceptional Customer Service: PANDA PCB takes pride in delivering outstanding customer service. Our knowledgeable team is here to assist you every step of the way.

Design Guidelines of Thick Film Heaters :

We compiled a Thick Film Heaters-Design Guidelines as attached for you to download, It is to better support our customers' needs in designing and applying Thick Film Heaters, This guide covers detailed information on product solutions, engineering design specifications, material properties, available manufacturing processes, and more.

We hope that this guide will assist customers in standardizing their design process while ensuring the manufacturability of the design data, ultimately improving product reliability and production efficiency. Customers are encouraged to refer to the guide when designing Thick Film Heaters to ensure adherence to best practices.

Materials Introduction of Thick Film Heater Solutions :

Substrates :

Alumina (Al2O3)

Aluminum Nitride (AlN)

Beryllium Oxide (BeO)

Zirconium Dioxide (ZrO2)

Aluminum (Al)

Stainless Steel

Max Application Temperature :

662 - 1832

1832

2300

2432

302

1202

Max Power Density (W/in²):

75

1010

250

300

400

200

Max Ramp Up Speed (°F/sec):

122

572

400

350

302

315

Thermal Conductivity (W/mK):

20-35

180-220

200-300

2.0-5.0

173

15

Density (g/cm³):

3.75

3.26

2.8

5.9

2.7

7.8

Dielectric Loss:

0.0001 - 0.001

0.0001 - 0.0005

0.0001 - 0.0002

0.0005 - 0.001

/

/

Dielectric Constant:

9.4 - 10.2

8.5 - 9.0

6.0 - 7.0

25 - 30

/

/

CTE, ppm/ºC:

6.0 - 8.0

4.0 - 5.0

7.0 - 9.0

10.0 - 11.0

24.0

5.8

Substrate Thickness (mm):

0.25, 0.38, 0.50, 0.635, 0.80,1.0, 1.25, 1.5, 2.0mm, Customizable

0.25, 0.38, 0.50, 0.635, 0.80,1.0, 1.25, 1.5, 2.0mm, Customizable

0.25, 0.38, 0.50, 0.635, 0.80,1.0, 1.25, 1.5, 2.0mm, Customizable

0.25, 0.38, 0.50, 0.635, 0.80,1.0, 1.25, 1.5, 2.0mm, Customizable

0.25, 0.38, 0.50, 0.635, 0.80,1.0, 1.25, 1.5, 2.0mm, Customizable

0.6, 1.0, 1.2, 1.5, 2.0, 2.5, 3.0, 4.0, 5.0, 6.0, 8.0, 10.0mm, Customizable

Typical Max. Dimension (inch):

6 x 12

5 x 11

6 x 6

4 x 4

12 x 24

20 x 24

Theoretical Total Wattage (W):

5400

55000

15000

20000

115200

57600

1, Thick film heaters are comprised of several layers, one of which is the dielectric layer. This layer is located between the metallic substrate and the printed traces, and its primary function is to separate the two layers. The dielectric layer is typically made from materials that are non-conductive such as ceramics or glass.

2, The need for a dielectric layer in Thick Film Heaters arises if the substrate is metallic, such as stainless steel or aluminum. The metallic substrate must be electrically insulated from the printed traces of either resistive pastes or conductor material. Otherwise, there could be a risk of electrical short-circuits and leakage currents.

3, For non-metallic base substrates, like ceramics, a dielectric layer may not be necessary since they are already non-conductive. However, it is still important to ensure proper insulation of the heater elements, as any electrical faults can lead to heater failure or even pose a safety risk.

4, The dielectric layer in thick film heaters is a crucial component that helps to electrically insulate the metallic substrate from the printed traces. It ensures proper electrical integrity and optimal performance of the heater.

1, The conductive layer is typically precious metal particles such as silver, palladium, gold or platinum and their respective alloys. Conductor traces are printed to apply voltage onto resistive traces to generate heat.

2, The voltage may be applied directly onto the resistive traces without conductor traces. if the heater substrate or the dielectric layer is coated continuously with a layer of resistive material, then, conductor traces are necessary to apply voltage.

3, Thick film heaters are electronic devices that utilize a resistive layer to generate heat when an electrical current is passed through it. The conductive layer of a thick film heater is an integral part of its structure and plays a crucial role in its operation.

1, The resistive layer of a Thick Film Heater is the component responsible for generating heat when an electrical current passes through it. It is specifically designed to have a high resistance, allowing it to convert electrical energy into heat energy efficiently.

2, The resistive paste is to be printed or coated onto the treated substrate to form heating traces or paths; It is called “functional material” as it is responsible generate heat in a custom thick film heater. The formula determines partially the resistivity or wattage of the heating traces or elements.

3, The resistive layer's properties, including its composition, thickness, and pattern design, directly influence the performance of the thick film heater. Factors such as the resistivity of the materials used, the uniformity of the layer, and its thermal stability are important considerations in achieving the desired heating capabilities and reliability of the heater.

1, Commonly used non-metallic materials for protective coatings include Overglazes (Glass-Glaze), enamel, polymers, and epoxies,depending on application conditions and environment.

2, Insulating-protective layer for custom heating element is printed or coated continuously to cover the heater assembly as the sheath of the heating element with several intents: mechanically protecting physical damage, electrically insulating the heating traces, preventing corrosion along with water resistance, and thermally withstanding maximum application temperatures.