Special Design Considerations Of Flexible Circuits And Rigid Flex PCB

There are some special components of flexible circuits and rigid flex pcb design that call for very early consideration and address mechanical issues that can affect functionality and/or lasting efficiency. Early factor to consider is essential since the mechanical issues will definitely influence circuit layout.

LAYOUT CIRCUIT TO CONSERVE MATERIAL

Conservation of material in flexible circuit manufacture assists to maintain manufacturing costs down, which is necessary due to the fact that flexible circuit materials have the tendency to be costly as compared to standard rigid products such as FR-4.

To attain the best economic benefit for flexible circuits fabrication, the specific components ought to be provided in a panel layout and oriented to supply optimal material application. The method of enhancing the variety of circuits each panel is commonly called nesting. The term optimizing is utilized in place of the seemingly many more logical term making the most of for a factor. The layout of a flex PCB and rigid flex PCB should be based on end usage. Some usages demand that parts of the flex circuit be effectively oriented relative to the grain instructions of the aluminum foil, such as vibrant flexing, where stretching locations are preferably oriented with the equipment or long instructions of the foil roll rather than the transverse or width direction. This may not lead to taking full advantage of material usage for circuit building and construction, yet instead maximizing the variety of circuits. In some cases, nevertheless, there is a possibility to lay the circuit out in different ways to get one of the most from the product.
Proper circuit nesting can substantially enhance panel yield and lower total expense. If folding can be endured as an assembly procedure, return can be made best use of. For vibrant flex circuit and rigid flex PCB styles, the grain instructions requirement may affect layout.

While nesting is consistently performed by the manufacturer, the designer could help in this procedure by making the most of that flexible circuits can be bent and folded. Thus, adding a tiny size to a circuit arm could allow a circuit to be produced many more financially as long as the customer doesn’t mind adding a folding procedure to the assembly process.

SERVICE LOOPS

The addition of a percentage of length to the flex circuit beyond the basic design demand is recommended for many flex PCB and rigid flex PCB applications. This little extra size of material is frequently described as the company loophole length.
The function of the service loophole is to offer sufficient added length to help with both assembly of the item and maintenance of the product when in the field. The added length likewise assists to make up for tiny, unexpected variations in both the bundle and also the rigid flex PCB circuits.

STAGGERED LENGTH CIRCUITS

Staggered length design practice is commonly employed for convenience of bending multilayer and also rigid flex PCB designs. The technique is completed by including somewhat to the size of each doing well flex layer, relocating away from the bend span.

An usual general rule is to add length equal to approximately 1.5 times the specific layer thickness, yet the worth could vary based upon the tightness of the bend and the number of layers. As a result, it is recommended that some modeling be performed ahead of devoting to make. A paper doll mock-up can be extremely instructional as a fast check. The extra length with each succeeding layer aids beat whatever tensor stress could have otherwise been built up in the outer steel layers of the multilayer Rigid Flex PCB and also prevents fastening of the facility of bend layers.

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