If the circuit design is relatively simple, the total volume is not large, and the space is suitable, most of the traditional internal connections are much cheaper. If the circuit is complex, handles many signals or has special electrical or mechanical performance requirements, Flexible PCB cables are a better design choice. When the size and performance of the application exceed the capabilities of a rigid circuit, the flexible assembly method is the most economical. Flexible circuits can be made on a single sheet of film with 12 mil pads with 5 mil via holes inside and 3 mil lines and spacing. Therefore, it is more reliable to mount chips directly on the film.
The high cost of raw materials is the main reason for the high price of flexible circuits. The price of raw materials varies greatly, the cost of the lowest cost of polyester flexible circuits used in the cost of raw materials used in rigid circuits is 1.5 times; high-performance polyimide flexible circuits are up to four times or more.
The flexible nature of the material makes it less susceptible to automated processing during manufacturing, which leads to lower yields, and defects during final assembly, including peeling off of flexible attachments and line breakage. Under the high stresses caused by bending or moulding, it is often necessary to choose reinforcement or reinforcing materials. Despite its high raw material costs and manufacturing hassles, the foldable, bendable, and multi-layer patchwork features will result in a reduction in overall component size and a subsequent reduction in the materials used, resulting in a lower total assembly cost.
The flexible circuit industry is in the midst of small but rapid growth. The polymer thick film method is a highly efficient, low-cost production process. The process selectively screen prints conductive polymer inks on inexpensive flexible substrates. A representative flexible substrate is PET, and the polymer thick film conductors include screen-printed metallic fillers or toner fillers. The polymer thick film method is inherently clean, uses lead-free SMT adhesives, and does not require etching. Because of its use of additive processes and low substrate costs, polymer thick-film circuits are 1/10 the price of copper polyimide thin-film circuits; and 1/2 to 1/3 the price of rigid circuit boards.
The polymer thick film method is particularly suitable for the control panel of the device. In mobile phones and other portable products, the polymer thick film method is suitable for printed circuit board components, switches and lighting devices into polymer thick film circuit. Both cost savings and reduced energy consumption are achieved.
Generally speaking, flexible circuits do cost more than rigid circuits and are more expensive. When flexible boards are manufactured, in many cases they have to face the fact that many of the parameters are out of tolerance. The difficulty in manufacturing flexible circuits lies in the flexibility of the material.
