Flexible Thick Film PCB

Flexible Thick Film PCBs, also known as Flexible Thick Film Sensors, are specialized hybrid circuits that use flexible substrates made of polyimide (PI) and polyester (PET), combined with thick-film technology to precisely print conductive, resistive, and insulating materials, forming flexible circuit boards that integrate resistors, capacitors, sensors, and other functional modules, offering characteristics such as lightweight, flexibility, heat resistance, and high stability, making them ideal for high-tech fields like medical devices, wearable technology, automotive electronics, and industrial control, particularly in applications that require high precision and reliability.

Flexible Thick Film PCBs offer single and double-sided flexible thick film circuits for low current applications. By using the screen-printing process to print various types of pastes, hybrid circuits can be created cost-effectively. The configurations of thick film flexible PCBs are also available in different processes, such as etching copper images on one side and printing paste patterns on the other side, double-sided etching copper patterns, or double-sided conductive silver paste printing.

Flexible Thick Film Sensors are widely used across various industries due to their flexibility, high performance, and ability to withstand harsh environments. They are commonly found in consumer electronics like smartphones and wearable devices, automotive electronics, medical devices, industrial control systems, aerospace applications, IoT devices, and RF (Radio Frequency) circuits. These PCBs offer excellent durability under high temperatures, vibrations, and moisture, making them ideal for use in high-performance, compact designs that require reliable, long-lasting functionality. Their versatility and small form factor make them a preferred choice for applications where space-saving and high-density integration are essential.

Features of Flexible Thick Film PCB :

1, Reliable Conductor and Resistor Printing: Flexible Thick Film PCBs incorporate reliable silver conductors or carbon resistors that are printed on flexible substrates using standard PCB processing techniques. This ensures stable and consistent electrical performance.

2, Flexibility: As the name suggests, these PCBs offer flexibility in their design and construction. They can be bent, twisted, or folded to fit into tight spaces or conform to unconventional shapes.

3, Compatibility: Flexible PCBs can work with almost any connector or component, providing versatility in terms of integration with other electronic devices or systems.

4, Tight Tolerance: Flexible Thick Film PCBs can achieve tight tolerances in linearity <+/-1%. This ensures precise and accurate performance in various electronic circuits.

5, Heat Dissipation: Compared to rigid circuit board materials, flexible PCBs, particularly those made with polyimide or similar polymers, disperse heat more effectively. This makes them suitable for use in applications where heat dissipation is crucial.

6, Higher Signal Integrity: Compared to ordinary glass-fiber laminates, Flexible Thick Film PCBs offer higher signal integrity, ensuring reliable transmission of electrical signals.

7, Excellent Performance in Harsh Environments: Flexible Thick Film PCBs exhibit superior resistance to radiation and chemicals, making them suitable for applications in harsh environments where exposure to these elements is a concern.

8, Impedance Control: Flexible PCBs can be advantageously used for impedance control, allowing for better signal integrity and reduced electromagnetic interference.

9, Temperature Resistance: Flexible Thick Film PCBs can withstand high temperatures ranging from -200°C to 400°C, allowing them to operate reliably in extreme temperature conditions.

10, Wide Range of Resistivity Values: Flexible PCBs offer a wide range of resistivity values, ranging from 1.0 ohm/square up to gig-ohm values (customizable). This allows for customization based on specific application requirements.

Flexible Thick Film PCBs make them well-suited for applications that require flexibility, precise performance, heat dissipation, temperature resistance in challenging environments. Please refer to Thick Film Resistor PCB for more informations.

Product Types of Flexible Thick Film PCB :

1, Flexible Potentiometers

2, Printed Flexible Electronics

3, Flexible Heaters (PI and PET)

Advantages of Flexible Thick Film PCB :

1, Lower Toughness, Good Manufacturability: Lower toughness is benefit for standing more thermal stress and reducing the joint cracking risk. By the way, Some flexible material can use laser or chemical etch create pads or window then could be used in double access applications.

2, Excellent Flexibility: Stable and repeating flexibility is helpful for 3-D electronic products assembly. During execution, the flexible thick film PCB can connect to multiple planes. It reduces the space and weight faced by traditional circuit boards. At the same time, it can easily flex the flexible PCB according to our requirements to various levels at the installation time without damaging the board.

3, Accurate Designs: Automated machinery designed and assembled the flexible thick film PCBs. The automated system helps reduce errors and ensures accuracy as the essential requirement for electronic devices.

4, Improved Air Flow: Flexible Thick Film PCBs are designed to dissipate heat better and improve airflow. Circuits on FR4 boards stay cooler as a result of this. In addition to improving airflow, electronic circuit boards perform better over the long term.

5, Great High Temperature Performance: PI material of Flexible PCB could be operated under high temperature environment then can fit for high temperature applications.

6, Freedom of Design: Flexible Thick Film PCBs can have more layers providing design freedom to designers. It is easy to make flexible thick film PCB in several forms, including one-sided, two-sided, and multilayered. In addition, Flexible PCB configurations with multiple interconnections are possible with this product. Platted through-hole and surface-mounted components can Flexible PCB accommodate.

7, High System Reliability: Early Flexible Thick Film PCB had a lot of interconnections. As a result, circuit boards often fail due to interconnection failures. Nowadays, the number of interconnection points on thick film flexible PCBs can reduce according to requirements. Consequently, they have become more reliable under challenging conditions. Furthermore, using polyimide material improves this PCB's thermal stability.

8, Thin Dielectric: Thin dielectric could have better flexibility and better heat transfer, those will be benefit for structure design and thermal management. that means thick film flexible PCB could be bended and binding with rigid-flex technology then can reduce connector and terminator using that can reduce weight.

9, High Space Utilization: Flexible Thick Film PCBs can replace many connecting parts and join multi plane boards then by these strength can saving space and make design easier. Other solutions may not work in applications that require thick film flexible PCB boards. Thin, lightweight, and able to fold and bend easily, the thick film flexible PCB can place in areas where other components are impossible. In addition, rigid-flex engineers often use 3D packaging geometry to reduce package size further.

Applications of Flexible Thick Film Sensors :

Flexible Thick Film Sensors are a type of special sensor that uses flexible base materials and thick film technology. They are known for their durability, flexibility, and capability to be used in various applications where space, weight, and movement considerations are crucial. Here are some of the key applications of Flexible Thick Film Sensors:

1, Medical Devices: In medical devices such as pacemakers, hearing aids, and diagnostic equipment, flexible thick film sensors are used because they can conform to the shape of the device and withstand harsh conditions.

2, Automotive Industry: In vehicles, these sensors are used in applications like control systems, engine management systems, and inside dashboard instrumentation due to their high resistance to vibrations and high temperatures.

3, Consumer Electronics: Flexible Thick Film Sensorss are widely used in smartphones, tablets, laptops, wearables, and other consumer electronics due to their flexible nature and ability to fit into small spaces.

4, Telecommunications: In telecommunications equipment like routers, servers, and switches, flexible thick film sensors are used because they can accommodate high-speed signals without significant signal loss.

5, Aerospace and Defense: The aerospace and defense industries utilize flexible thick film sensors in applications like satellites, aircraft controls, and military-grade equipment because of their durability, lightweight nature, and ability to withstand extreme environmental conditions.

6, Industrial Applications: Flexible Thick Film Sensors are also used in various industrial applications like robotics and automation systems due to their ability to withstand high temperatures and resist wear and tear.

Remember, the selection of sensor type largely depends on the specific requirements of the application, including factors like operating conditions, space constraints, and performance needs.

Materials of Flexible Thick Film PCB :

Flexible Thick Film PCBs are made from several different materials, each chosen for their specific properties that contribute to the overall performance and flexibility of the PCB. Here are the primary materials used:

1, Base Material: The base material is typically a type of flexible plastic such as polyimide (PI), polyester (PET), or polyethylene naphthalate (PEN). Polyimide is the most commonly used due to its excellent thermal stability, mechanical toughness, and chemical resistance.

2, Conductive Layer: The conductive layer, which forms the circuits, is usually made from a thick film paste that primarily consists of metal powders like silver, gold, platinum, palladium, and their alloys. This paste is applied onto the base material via screen printing. The thickness of this layer can vary depending on the application requirements.

3, Dielectric Layer: A dielectric layer is used to insulate different conductive layers in multi-layer flexible PCBs. This layer is typically made of the same material as the base, such as polyimide, and is applied as a liquid then cured to form a solid layer.

4, Adhesive Layer: An adhesive layer may be used to bond the various layers together. This is typically made from thermosetting adhesives like epoxy or acrylic. However, adhesiveless construction methods are also available, where the copper is directly bonded to the base material, providing better heat resistance and dimensional stability.

5, Coverlay: A coverlay, typically made from the same material as the base (like polyimide), is used to protect the conductive circuits. It's similar to the solder mask on a rigid PCB.

6, Stiffeners: In some designs, stiffeners made from materials like FR4, polyimide, or metal might be added to provide extra support to certain areas of the PCB, such as connector sites.

Remember, the choice of materials can significantly impact the performance, reliability, and cost of the Flexible Thick Film PCB. Therefore, careful consideration should be given to material selection based on the specific requirements of the application.

Multi-Wire Wipers Used For Flexible Thick Film PCB :

Multi-Wire Wipers are crucial components designed to transmit voltage and signals. They perform linear or rotational sliding over the surfaces of resistive materials (thick film resistors) to adjust resistance values and act as contact elements in voltage dividers.
Wiper design is extremely critical for the efficiency and life of the sensor assembly, When designing the wiper, it is very important to consider contact resistance, working-hight (load), repeatability, hysteresis, the resistive material used, and in particular, the wiper material itself, its shape and the wiper pressure.

We also provided custom Multi-Wire Wipers (Contact) for customer if needs, we can manufacture the wipers according to customer's design requirements or specification, For more information about wipers, Please refer to Multi-Contact Wipers.

Why Choose PANDA PCB For Flexible Thick Film Sensors ?

1, Experience and Expertise: PANDA PCB Group has extensive experience and expertise in the field of PCB manufacturing. They understand the intricacies of designing and manufacturing flexible thick film sensors, which can lead to high-quality final products.

2, Advanced Technology: PANDA PCB uses advanced technology and equipment in their manufacturing processes, ensuring precision, reliability, and high performance in our flexible sensor PCB products.

3, Quality Assurance: Our company has strict quality control measures in place to ensure that all their PCBs meet or exceed industry standards. This can give you confidence in the reliability and durability of their products.

4, Customization: We offer customized solutions to meet the specific needs of your project. We can adjust materials, layer counts, thicknesses, and other specifications to match your requirements.

5, Excellent Customer Service: PANDA PCB is known for its excellent customer service. We work closely with their clients throughout the design and manufacturing process to ensure client satisfaction.

6, Competitive Pricing: While maintaining high-quality standards, PANDA PCB also offers competitive pricing, making them a cost-effective choice for flexible thick film PCBs.

7, Fast Turnaround Time: We understand the importance of time in any project and hence, they offer fast turnaround times without compromising on the quality.

Capabilities of Thick Film Solutions Are As Follows :

Items :

Typical Values

Advanced Capabilities

1, Substrates :

FR4, Ceramic ( AI203, ALN, BeO, ZrO2), Polyimide (Flexible PI), Stainless Steel (SUS304), Mica

FR4, Ceramic ( AI203, ALN, BeO, ZrO2), Polyimide (Flexible PI), Stainless Steel (SUS304), Mica

2, Conductor (Paste) Materials :

Copper, Silver , Gold , Silver-Palladium, Palladium-Gold, Platinum-Silver, Platinum-Gold

Copper, Silver , Gold , Silver-Palladium, Palladium-Gold, Platinum-Silver, Platinum-Gold

3, Thick Film Carbon Thickness (Height) :

15um +/-5 um

30um +/-5 um

4, Conductor Thickness (Height) :

12um+/-5um

20um+/-5um

5, Min Width of Thick Film Line :

0.30 mm +/-0.05 mm

0.20 mm +/-0.05 mm

6, Min Space of Thick Film Line :

0.30 mm +/-0.05 mm

0.20 mm +/-0.05 mm

7, Min Overlap (Carbon to Conductor) :

No less than 0.25mm

0.20mm (Minimum)

8, Sheet Resistivity (ohms/square):

Printed resistors in milli ohm to mega ohm range (Customizable) with tolerances of 1-10% are fabricated and protected with overglaze materials.

Printed resistors in milli ohm to mega ohm range (Customizable) with tolerances of 0.5-10% are fabricated and protected with overglaze materials.

9, Resistor Value Tolerance (ohms) :

+/-10.0% (Standard) (Customizable)

+/-0.5% (Laser trimming)

10, Linearity :

+/-1.0% (Standard) (Customizable)

+/-0.2 ~ +/-0.5% (Laser trimming)

11, Synchronism of Double Channels :

+/-2.0% (Standard) (Customizable) (Potentiometers)

+/-1.0% (Laser trimming) (Potentiometers)

12, Durability of Carbon Ink (Life time) :

0.5 Million (Min), 2.0 Million (Standard)

5.0-10.0 Million (Max) with Surface Polishing

13, Working Temperature :

－ 40ºC /＋150ºC

－ 40ºC /＋180ºC

Paste ( Materials) :

Conductor Width/Space

Soldering / Bonding

Gold :

8/8mil (0.20/0.20mm)

Gold is a good conductor material and allows thermo-compression gold wire bonding and eutectic die attachment. It is, of course, costly and has poor solderability.

Silver :

8/8mil (0.20/0.20mm)

Soldering & Silver is lower in cost, and solderable, but is not leach-resistant with tin/lead solders.More seriously, silver atoms migrate under the influence of DC electric fields, both causing short-circuits and reacting with many of the resistor paste formulations.

Platinum-Silver :

6/6mil (0.15/0.15mm)

Soldering & Surface Mount, Palladium and platinum alloyed to the gold and silver produce good conductor pastes,with good adhesion to the substrate, good solderability, and moderately good wire bonding characteristics.. Copper and nickel are examples of materials that have been proposed for paste systems as substitutes for noble metals.

Palladium-Silver :

8/8mil (0.20/0.20mm)

Soldering & Surface Mount ,Solderable, Wire bondable, (good aged adhesion general purpose), Silver-palladium conductor inks are the most commonly used materials, with both price and performance (primarily resistance to solder) increasing with palladium content.

Platinum-Gold :

6/6mil (0.15/0.15mm)

Soldering & Au or Al Wire Bonding, Solderable (excellent aged adhesion with no migration).

Palladium-Gold :

8/8mil (0.20/0.20mm)

Soldering & Au or Al Wire Bonding, Wire bondable.

Performances :

Common Values/Range

Description

Resistance Value :

1Ω to several MΩ

The resistance value depends on the type and ratio of carbon black, typically ranging from 1Ω to Mega ohm.

Resistance Tolerance :

±1% to ±10%

High-precision resistors can achieve ±0.1% tolerance used laser trimming process.

Temperature Coefficient (TCR) :

±50ppm/°C to ±200ppm/°C

High-quality resistive paste should have a low TCR, preferably below ±100ppm/°C.

Stability :

≤1%

Resistors must undergo high-temperature aging and humidity tests to ensure stability.

Sintering Temperature :

850°C to 950°C

The sintering temperature for carbon paste depends on material properties, typically in this range.

Conductivity :

10⁶ S/m to 10⁸ S/m

Conductivity depends on the type and ratio of carbon black, affecting resistance precision and stability.

Surface Smoothness :

Ra≤ 1 μm

The surface must be free of cracks, bubbles, and non-uniform layers to ensure good mechanical and electrical properties.

Insulation Resistance :

≥10⁹ Ω

Carbon paste should have good insulation properties to avoid leakage or short circuits.

Mechanical Strength :

≥100 MPa

The resistive layer must have good compressive and bending strength to ensure the reliability of the resistor.

Volatility :

Solvent residue ≤ 1%

High volatility solvents help with even coating and drying, but excessive volatility may affect electrical performance.

Oxidation Resistance :

>1000 hours

High-quality carbon paste should have strong oxidation resistance to extend the service life.

Humidity Resistance :

≥1000 hours

Resistors should be able to withstand high-humidity conditions to ensure long-term stable performance, no significant changes.