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The following are the two main characteristics of flexible circuit boards:
2. The Economics of Flexible Circuits
When it comes to the economics of flexible circuits, there are a few key considerations to keep in mind. If the circuit design is relatively simple, the total volume is not large, and the space is suitable, traditional interconnection methods are generally much cheaper. However, if the circuit is complex, handles many signals, or has special electrical or mechanical performance requirements, a flexible circuit is the better design choice. Flexible assembly is most economical when the size and performance of the application exceed the capabilities of rigid circuits. For example, 12mil pads with 5mil through-holes and 3mil lines and spaces can be fabricated on a single film, making it more reliable to mount the chip directly on the film. These films also lack flame retardants that may be a source of ionic contamination, and they can cure at higher temperatures, resulting in higher glass transition temperatures. The cost savings of flexible materials over rigid materials can be attributed to the elimination of connectors.
The high cost of raw materials is the primary reason for the high price of flexible circuits. The price of raw materials varies greatly, and the cost of raw materials used in the lowest cost polyester flexible circuit is 1.5 times that of the raw materials used in rigid circuits. High-performance polyimide flexible circuits can be as high as 4 times or more. Additionally, the flexibility of the material makes it difficult to automate processing during the manufacturing process, resulting in lower yields. Defects in the final assembly process, including peeling off flexible attachments and line breakage, are more likely to happen when the design is not suitable for the application. Under high stresses caused by bending or forming, it is often necessary to select reinforcing materials. Despite the high raw material cost and manufacturing challenges, the foldable, bendable, and multi-layer paneling function will reduce the size and overall assembly cost.
The flexible circuit industry is experiencing small but rapid development. The polymer thick film method is an efficient and low-cost production process that selectively screen prints conductive polymer inks on inexpensive flexible substrates, with PET being a representative flexible substrate. Polymer thick film circuits are 1/10 of the price of copper polyimide film circuits and 1/2 to 1/3 of the price of rigid circuit boards due to its use of additive process and low cost of substrates. The polymer thick film method is especially suitable for the control panel of devices and can save costs and reduce energy consumption.
Despite the above-mentioned cost factors, the price of flexible assembly is falling and becoming more similar to traditional rigid circuits. This is due to the introduction of newer materials, improved production processes, and changes to the structure. Newer materials allow for more precise lines due to thinner copper layers, making components lighter and more suitable for fitting into small spaces. In addition, the flexible circuit has flame retardant properties after some adhesives have been removed, speeding up the uL certification process and further reducing costs. Flexible circuit board solder masks and other surface coatings also reduce the cost of flexible assembly.
In the coming years, smaller, more complex, and more expensive flex circuits will require newer methods of assembly and the addition of hybrid flex circuits. The challenge for the flexible circuit industry is to take advantage of its technology to keep pace with computing, telecommunication, consumer demand, and dynamic markets. Flexible circuits will also play an important role in the lead-free movement.
The following are the two main characteristics of flexible circuit boards:
2. The Economics of Flexible Circuits
When it comes to the economics of flexible circuits, there are a few key considerations to keep in mind. If the circuit design is relatively simple, the total volume is not large, and the space is suitable, traditional interconnection methods are generally much cheaper. However, if the circuit is complex, handles many signals, or has special electrical or mechanical performance requirements, a flexible circuit is the better design choice. Flexible assembly is most economical when the size and performance of the application exceed the capabilities of rigid circuits. For example, 12mil pads with 5mil through-holes and 3mil lines and spaces can be fabricated on a single film, making it more reliable to mount the chip directly on the film. These films also lack flame retardants that may be a source of ionic contamination, and they can cure at higher temperatures, resulting in higher glass transition temperatures. The cost savings of flexible materials over rigid materials can be attributed to the elimination of connectors.
The high cost of raw materials is the primary reason for the high price of flexible circuits. The price of raw materials varies greatly, and the cost of raw materials used in the lowest cost polyester flexible circuit is 1.5 times that of the raw materials used in rigid circuits. High-performance polyimide flexible circuits can be as high as 4 times or more. Additionally, the flexibility of the material makes it difficult to automate processing during the manufacturing process, resulting in lower yields. Defects in the final assembly process, including peeling off flexible attachments and line breakage, are more likely to happen when the design is not suitable for the application. Under high stresses caused by bending or forming, it is often necessary to select reinforcing materials. Despite the high raw material cost and manufacturing challenges, the foldable, bendable, and multi-layer paneling function will reduce the size and overall assembly cost.
The flexible circuit industry is experiencing small but rapid development. The polymer thick film method is an efficient and low-cost production process that selectively screen prints conductive polymer inks on inexpensive flexible substrates, with PET being a representative flexible substrate. Polymer thick film circuits are 1/10 of the price of copper polyimide film circuits and 1/2 to 1/3 of the price of rigid circuit boards due to its use of additive process and low cost of substrates. The polymer thick film method is especially suitable for the control panel of devices and can save costs and reduce energy consumption.
Despite the above-mentioned cost factors, the price of flexible assembly is falling and becoming more similar to traditional rigid circuits. This is due to the introduction of newer materials, improved production processes, and changes to the structure. Newer materials allow for more precise lines due to thinner copper layers, making components lighter and more suitable for fitting into small spaces. In addition, the flexible circuit has flame retardant properties after some adhesives have been removed, speeding up the uL certification process and further reducing costs. Flexible circuit board solder masks and other surface coatings also reduce the cost of flexible assembly.
In the coming years, smaller, more complex, and more expensive flex circuits will require newer methods of assembly and the addition of hybrid flex circuits. The challenge for the flexible circuit industry is to take advantage of its technology to keep pace with computing, telecommunication, consumer demand, and dynamic markets. Flexible circuits will also play an important role in the lead-free movement.
