All flex PCB layouts need to be made as tear-resistant as feasible. While the material could not be intrinsically tear-resistant, tear resistance can be enhanced by using specific functions in the flex PCB design. There are several feasible techniques that are explained below and also illustrated.
1. Huge radius in edge
2. Installed glass towel
3. Recessed slot
4. Hole in slit
5. Pierced opening at edge
6. Embedded aramid fiber
7. Added copper in corner
The complying with methods have actually been used efficiently to aid prevent tearing. One or more of the strategies can be utilized.
DISTANCE ALL INTERNAL CORNERS
The first line of protection against tearing is making particular that all interior edges are offered with one of the most generous radius feasible. This design method is one of the most vital as well as most basic of all techniques made use of to prevent tearing of the flex PCB manufacturing product.
LEAVE METAL IN CORNERS
The circuit design should, ideally, have little locations of copper provided for at interior corners to serve as tear stops at the inside of corner distance. This avoids, or at least minimizes, breeding of a tear via the polymer must a tear in the material initiate.
LAMINATE GLASS FABRIC IN CORNERS
Glass fabrics can be laminated flooring into corners during the fabrication process. Though not flexible, this method gives a durable corner building and has been favored in the past by army product developers. It is a costly option, nonetheless, as a result of the kind of preparation called for and also ought to just be made use of after careful consideration of the choices.
USAGE FLUOROPOLYMER COVERLAYER
Making use of fluoroplastics, such as Teflon ®, as coverlayers boosts tear resistance by virtue of the high tear resistance of the polymer itself. Fluoropolymers tend to extend, rather than tear, which adds sturdiness to the substrate. In high frequency PCB design, an additional benefit of using fluoropolymer coverlayers is that the dielectric constant of the coverlayer is much reduced.
UTILIZE OF RADIUSED SLOTS
Making use of slots with ends that have a radius to gain access to happy flex circuit attributes can additionally provide tear resistance. Generally, such attributes can conveniently be offered throughout the boxing operation or other flex PCB manufacturing procedure.
DRILLED HOLES AT CORNERS OR ENDS OF SLITS
Pierced or punched holes in corners or at the end of gain access to slits have been used successfully when flexible appendages need to be placed close together. This approach makes best use of the use of flex PCB manufacturing product, yet the hole dimension selected will certainly influence tear resistance. If the holes are extremely small the total robustness will certainly be decreased.
ARAMID FIBERS INSIDE CUT LINE
As a choice to glass cloth, aramid fibers routed through edges or along the whole overview of the flex PCB offer a special technique to quit flexible circuits tearing. The thin polymer fibers are high-strength as well as flexible, minimally influencing adaptability. Making use of aramid fibers is labor extensive and must just be made use of with consideration of the expense effect.
The option of approach to restrain or protect against tearing of the flex PCB is not a key worry. Just what is essential is that the developer makes use of some suitable method to protect versus tearing.
To sum up, all interior corners should be offered with span. It is necessary to repeat and emphasize that square or sharp inner corners are an invite to trouble and need to be studiously stayed clear of. If the location of the corner is to be permanently adhered to a rigid base, it is less important, yet still suggested, that a distance be used.