The use of rigid-flexible PCBs opens for many applications completely new possibilities and advantages regarding signal transmission, size, stability and long-term reliability.
In recent years, Hemeixinpcb has accumulated extensive expertise in costumer projects and commissions of the widest variety of designs and applications, from Aerospace to Medical devices and currently it supplies more than 1000 customers. With the broad range of technology we offer, you can make the best possible selection for any requirements in terms of performance and costs.
For first time designers and engineers it is a good idea to become familiar with the specifications that have reference to rigid-flex pcb manufacturing.
|Flex material-Kapton and other polyimide films||1/2 mil(12.5μm), 1 mil(25μm), 2 mil(50μm), 3 mil(75μm), 5 mil(125μm). Example: AP 8515R, AP 9111R, AP 8525R, AP 9121R, AP 9222R, AP 8535R, AP 9131R, AP 9232R, AP 8545R, AP 9141R. ect…|
|Coverlay||1 mil(25μm), 2 mil(50μm), 3 mil(75μm), Example: FR0110, FR0120, ect…|
|Rigid material- FR4||Variety of thicknesses between 0.003″ (0.08mm)and 0.125″ (3.18mm)|
|Copper weight||1/4 oz. (9μm), 1/3 oz. (12μm), 1/2 oz. (18μm), 1 oz (35μm), 2 oz. (71μm), 3 oz. (107μm), 5 oz. (175μm), 7 oz (254μm), 10 oz. (356μm)|
|Adhesive||1/2 mil (12.5μm), 1 mil (25μm), 2 mil (50μm), 3 mil (75μm), 4 mil (100μm)|
|Pressure-sensitive adhesive (PSA)||1 mil (25μm), 2 mil (50μm), 4 mil (100μm), 5 mil (125μm)|
|Stiffener||Copper, Aluminum, and other metals. Variety of thicknesses available|
|Stainless steel up to 20 mils(500μm)|
|Polyimide thickness between 1/2 mil (12.5μm), 1 mil (25μm), 2 mil (50μm), 3mil (75μm), 4 mil (100μm), 5 mil (125μm), 6mil (150μm), 7 mil (175μm), 8 mil (200μm), 9 mil (225μm), 10mil (250μm)|
|FR-4 thickness between 0.005″ (0.13mm)and 0.125″ (3.18mm)|
Designs that have one or more of the following may require the use of coverlay throughout in specific areas or layers:
“T” is the thickness of the flexible PCB
Calculate 150µm for a 1-layer, and 200µm for a 2-layer printed circuit board. It guarantees are already included.
Example: A 2-Layer rigid-flex PCB is 200 microns thick. From the formula above: 10 x 200 microns = 2000μm = 2mm.
The bookbinder design of an unbonded flex area can be used in regions where a sharp bend (radius to thickness ratios < 6) is required. This technique uses progressive lengths in the flex pcb area and is costly to manufacture because of tooling complexity, processing difficulties, and reduced yields.
To work out the additional length needed for each flexible circuit layer above the innermost layer, use the calculation given by IPC-2223:
Very common in the field of flex and rigid-flex pcb design is the use of hatched plan layers.
Hatched plan layers increasing the flexibility of Flex and ridged flex PCBs.
Each area in a rigid flexible circuit has its constraints; the mechanical designer shall give description details depending on the final requirements.
It is most cost effective to build a rigid-flex pcb with an even number of layers. All rigid portions of the circuit should have the same number and stack-up of layers.
Hemeixinpcb manufactures single, double, and multi-layer flex circuits using modern rigid-flex materials and stack up. Designs comply with IPC 2223C standards, which define the elimination/minimization of adhesive use within rigid areas, use of adhesiveless based substrates, and use of selective/partial coverlay stack up.