Flexible Circuit Manufacturing Services

Double Sided Flex PCB Manufacturer

Looking for reliable double sided flex PCB manufacturing services? Our company offers top-quality PCBs with high flexibility, reliability, and cost-effectiveness. Contact us today to learn more!

What is Double Sided Flex PCB?

A double-sided flex PCB is a flexible circuit board with conductive traces on both sides of the flexible substrate. This allows for more complex and compact designs and increased functionality compared to single-sided flex PCBs.

The flexible substrate used in a double-sided flex PCB is typically made of a thin, flexible material such as polyimide or polyester. The conductive traces are made of a thin layer of copper that is etched onto the substrate using a chemical process.

One of the key advantages of double-sided flex PCBs is their ability to provide a high degree of flexibility and reliability. This makes them ideal for use in applications where space is at a premium, or where the circuit board needs to bend or flex to accommodate a specific design requirement.

Double Sided Flex PCB

Structure of Doube Sided Flex PCB

The structure of a double-sided flex PCB allows for increased routing flexibility and component density, as well as improved reliability and durability compared to rigid PCBs.

The structure of a double-sided flex PCB typically consists of the following layers:

Double-sided Flex PCB Structure

  1. Base material: The base material of a double-sided flex PCB is typically made of polyimide (PI) or polyester (PET) film, which provides flexibility and durability to the PCB.

  2. Conductive layers: A double-sided flex PCB has conductive layers on both sides of the base material, which are made of copper foil. The copper foil is typically bonded to the base material using an adhesive layer.

  3. Coverlay: Coverlay is a protective layer that is applied over the conductive layers to protect them from environmental factors such as moisture, dust, and chemicals. Coverlay is made of a thermoset material such as epoxy or polyimide and is typically applied using a lamination process.

  4. Solder mask: Solder mask is a layer of polymer that is applied over the copper traces to protect them from oxidation and to prevent accidental soldering. The solder mask is typically applied using a liquid photo-imageable (LPI) process.

  5. Surface finish: The surface finish is a layer of metal that is applied to the exposed copper surfaces to improve solderability and prevent oxidation. Common surface finishes for double-sided flex PCBs include HASL, ENIG, OSP, immersion silver, and gold plating.

Types of Double-Sided Flex Circuits

Depending on the circuit design requirements, double-sided flex circuits can be fabricated with a protective layer on a single side, both sides, or neither sides. These flexible circuits are differentiated into categories based on the cover layer and Plated Through Holes (PTH).

  • With PTH and Cover layer
  • With PTH without a Cover layer
  • With a Cover layer, without PTH
  • Without PTH or a Cover layer
2 Layer Flexible PCB

Applications of Double Sided Flex PCB

Double sided flex PCBs are widely used in various applications that require high flexibility and durability. Here are some examples of the applications of double sided flex PCBs:

  1. Consumer electronics: Double sided flex PCBs are used in smartphones, tablets, wearable devices, and other portable electronics where space is at a premium and the circuit board needs to be flexible to fit into a small form factor.

  2. Automotive electronics: Double sided flex PCBs are used in automotive electronics such as dashboard displays, infotainment systems, and climate control systems. The flexibility of the circuit board allows it to bend and conform to the shape of the dashboard or other areas of the vehicle.

  3. Medical devices: Double sided flex PCBs are used in medical devices such as pacemakers, defibrillators, and other implantable devices. The flexibility of the circuit board allows it to conform to the shape of the body and reduce the risk of damage or breakage.

  4. Aerospace and defense systems: Double sided flex PCBs are used in aerospace and defense systems such as satellites, communication systems, and missile guidance systems. The flexibility of the circuit board allows it to withstand the harsh environmental conditions of space and the battlefield.

  5. Industrial automation: Double sided flex PCBs are used in industrial automation systems such as robots, sensors, and control systems. The flexibility of the circuit board allows it to bend and conform to the shape of the equipment, reducing the risk of damage or breakage.

In summary, double sided flex PCBs are used in a wide range of applications where flexibility, durability, and space-saving design are critical factors. They enable the development of more advanced and sophisticated electronic devices, and will continue to play a key role in the advancement of technology in the future.

Advantages of Double-Sided Flex PCB

Double sided flex PCBs offer numerous advantages over traditional rigid circuit boards. Their thin and lightweight design allows for more compact and space-saving designs, while their increased functionality provides for more complex circuitry in a smaller form factor. Double sided flex PCBs are also highly durable and flexible, making them ideal for applications that require resistance to vibration and mechanical stress, as well as the ability to bend and conform to the shape of the product. Additionally, double sided flex PCBs are cost-effective and lighter than traditional rigid circuit boards, which is especially important in weight-sensitive applications such as aerospace and defense systems. These advantages make double sided flex PCBs an attractive choice for a wide range of applications, including consumer electronics, automotive electronics, medical devices, industrial automation, and aerospace and defense systems.

  1. Space-saving design: Double sided flex PCBs are thinner and lighter than traditional rigid circuit boards, allowing for more compact designs and the ability to fit into smaller spaces.

  2. Increased functionality: With conductive traces on both sides of the flexible substrate, double sided flex PCBs can provide more complex and dense circuitry, allowing for increased functionality in a smaller form factor.

  3. Improved durability: The flexible substrate used in double sided flex PCBs is more resistant to vibration and mechanical stress, making them more durable than rigid circuit boards. This also reduces the risk of damage or breakage during handling or transportation.

  4. High flexibility: Double sided flex PCBs are able to bend and flex, allowing them to conform to the shape of the product they are used in. This makes them ideal for use in products that need to be bent or flexed, such as wearable devices, medical devices, and automotive electronics.

  5. Reduced weight: Double sided flex PCBs are lighter than traditional rigid circuit boards, which is particularly advantageous in weight-sensitive applications such as aerospace and defense systems.

  6. Lower cost: Compared to traditional rigid circuit boards, double sided flex PCBs can be manufactured at a lower cost due to their simpler construction and reduced material requirements.

Overall, double sided flex PCBs offer numerous advantages over traditional rigid circuit boards, including improved durability, flexibility, space-saving design, and reduced cost. They are ideal for use in a wide range of applications, including consumer electronics, automotive electronics, medical devices, aerospace and defense systems, and industrial automation.

Design Considerations for Double Sided Flex PCB

When designing a double sided flex PCB, there are several key considerations that must be taken into account to ensure the best performance and reliability of the final product. Here are some of the main design considerations for double sided flex PCBs:

  1. Flexibility and bend radius: The flexibility of the flexible substrate used in the double sided flex PCB is a critical factor. The design must take into account the minimum bend radius of the flexible substrate to prevent damage or breakage.

  2. Circuitry placement: When placing the circuitry on both sides of the flexible substrate, it’s important to consider the location and orientation of components and their interconnections to ensure optimal functionality and reliability.

  3. Trace width and spacing: The width and spacing of traces must be carefully considered to prevent crosstalk and signal interference. Designers must also ensure that traces are wide enough to carry the required current without causing overheating or damage to the board.

  4. Solder joint placement: Solder joints are crucial for electrical connections in a double sided flex PCB. Designers must consider the placement of solder joints, as well as the type of solder to be used to ensure proper adhesion and bonding.

  5. Component mounting: Components must be mounted securely and correctly on both sides of the flexible substrate to prevent displacement or damage during operation or handling.

  6. Thermal management: Double sided flex PCBs can generate heat, which can affect the performance and reliability of the product. Designers must consider thermal management techniques such as heat sinks, thermal vias, and proper airflow to dissipate heat and maintain optimal operating temperature.

  7. Environmental factors: Double sided flex PCBs may be used in harsh environments, so designers must consider factors such as moisture, temperature, and chemical exposure, and choose materials that are resistant to these conditions.

In summary, designing a double sided flex PCB requires careful consideration of several factors to ensure the best performance, reliability, and durability of the final product. Proper attention to these design considerations can lead to a high-quality double sided flex PCB that meets the requirements of its intended application.

Double Sided Flex PCB Manufactauring Process

The manufacturing process of double sided flex PCBs involves several steps, including:

  1. Preparing the flexible substrate: The flexible substrate is prepared by cutting it to the required size and shape. The substrate is then cleaned to remove any dirt or contaminants that could affect the adhesion of the copper traces.

  2. Applying the copper layers: The copper layers are then applied to both sides of the flexible substrate using a process called electroless plating. This involves immersing the substrate in a chemical solution that deposits a thin layer of copper onto the surface.

  3. Photolithography: The copper layers are then covered with a photosensitive material and exposed to UV light through a photomask, which creates the circuitry pattern on the copper surface. The areas not covered by the photosensitive material are then etched away using an acid solution, leaving behind the copper traces.

  4. Drilling: Holes are then drilled into the substrate where components will be mounted or where interconnections between layers are needed.

  5. Plating and solder mask: The substrate is then plated with a thin layer of gold or other precious metal to improve the reliability and performance of the circuitry. A solder mask is then applied to protect the circuitry and prevent solder bridges between components.

  6. Assembly and testing: The components are then assembled onto the double sided flex PCB and tested to ensure that the circuitry functions properly.

  7. Finishing: The final step involves finishing the double sided flex PCB by adding any necessary coatings or finishes to improve its durability, appearance, and performance.

Testing Methods for Double Sided Flex PCB

Testing double sided flex PCBs is an essential part of the manufacturing process to ensure the quality and reliability of the final product. Here are some of the most common testing methods for double sided flex PCBs:

  1. Electrical testing: Electrical testing involves applying a voltage to the circuitry and measuring the current and resistance of the traces and components. This can detect any open or short circuits, as well as other defects such as improper component values or incorrect polarity.

  2. Continuity testing: Continuity testing is used to verify that there is a connection between two points in the circuit. This is typically done using a multimeter to check for resistance or voltage across the circuit.

  3. Thermal testing: Thermal testing is used to determine how well the double sided flex PCB handles heat. This can involve applying a controlled amount of heat to the board and measuring the temperature, or exposing the board to a temperature chamber to simulate the conditions it will be exposed to in its intended application.

  4. Vibration testing: Vibration testing involves subjecting the double sided flex PCB to mechanical vibrations to simulate the conditions it will be exposed to during use. This can detect any weak or damaged areas in the circuitry or components.

  5. Flex testing: Flex testing involves bending or flexing the double sided flex PCB to test its durability and resistance to mechanical stress. This can be done manually or using a specialized testing machine that applies controlled amounts of stress to the board.

  6. Environmental testing: Environmental testing involves exposing the double sided flex PCB to different environmental conditions such as temperature, humidity, or chemicals to test its resistance to these conditions. This can help detect any weaknesses in the circuitry or components that may affect performance or reliability.

Trusted Flex PCB Manufacturer

We are a reliable manufacturer and supplier of flex PCBs, offering high-quality solutions for single-sided, double-sided, and multi-layer flex PCB prototyping and volume production, as well as flexible PCB assembly services to meet our customers’ diverse needs.

As a trusted flex PCB manufacturer and supplier, we are committed to providing our customers with quality products and services. We have a professional R&D and production team that uses advanced manufacturing technology and equipment to ensure our products meet customers’ requirements and standards. Our quality management system is strictly managed according to ISO standards to ensure stable and reliable product quality.

If you are looking for a reliable flex PCB manufacturer and supplier, please feel free to contact us. We will provide you with quality products and services to meet your different needs.

Double Sided Flex PCB Manufacturing Service

Double Sided Flex PCB Manufacturing Process

Manufacturing CapabilityDetails
MaterialsPolyimide (PI) and polyester (PET) films
LayersUp to 4 layers
Copper WeightStandard copper weight for double-sided flex PCBs is 1oz (35 µm)
Minimum Trace/Space3 mil (0.076 mm)
Minimum Hole Size0.2 mm (8 mil)
Surface FinishHASL, ENIG, OSP, immersion silver, and gold plating
Solder MaskLPI solder mask in various colors
SilkscreenWhite or black silkscreen
Maximum Panel Size457 x 610 mm (18 x 24 inches)
Quality StandardsManufactured according to IPC Class 2 or Class 3 standards
TestingElectrical testing, impedance testing, and other tests as per customer requirements

Note: These are general capabilities and may vary depending on specific customer requirements and project specifications. Please contact us for more information on our double-sided flex PCB manufacturing capabilities.

FAQs for Double Sided Flex PCB

A double-sided flex PCB is a type of flexible printed circuit board that has conductive traces on both sides of the substrate, allowing for increased circuit density and routing flexibility.

Double-sided flex PCBs offer increased routing flexibility and component density, as well as improved reliability and durability compared to rigid PCBs.

The most common materials used for double-sided flex PCBs are polyimide (PI) and polyester (PET) films.

Double-sided flex PCBs can have up to four layers.

The minimum trace/space for double-sided flex PCBs is typically 3 mils (0.076 mm).

The minimum hole size for double-sided flex PCBs is typically 0.2 mm (8 mils).

Common surface finishes for double-sided flex PCBs include HASL, ENIG, OSP, immersion silver, and gold plating.

Electrical testing and impedance testing are commonly used for double-sided flex PCBs. Additional testing may be performed as per customer requirements.

Double-sided flex PCBs are manufactured according to IPC Class 2 or Class 3 standards, depending on the customer's requirements.

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