All flex PCB designs must be made as tear-resistant as possible. While the product might not be fundamentally tear-resistant, tear resistance can be enhanced by utilizing particular features in the flex PCB design. There are a number of feasible methods that are described listed below and highlighted.
1. Huge distance in corner
2. Embedded glass cloth
3. Recessed slot
4. Opening in slit
5. Pierced opening at corner
6. Installed aramid fiber
7. Added copper in edge
The complying with techniques have actually been utilized efficiently to aid prevent tearing. One or more of the techniques can be used.
SPAN ALL INTERNAL CORNERS
The initial line of protection versus tearing is to make particular that interior edges are supplied with the most generous distance possible. This design method is one of the most important and also easiest of all approaches made use of to prevent tearing of the flex PCB fabrication product.
LEAVE METAL IN CORNERS
The circuit design should, preferably, have little locations of copper provided for at interior corners to work as tear quits at the inside of edge distance. This prevents, or at the very least reduces, propagation of a tear with the polymer should a tear in the product initiate.
LAMINATE GLASS FABRIC IN CORNERS
Glass fabrics can be laminated right into edges throughout the fabrication procedure. Though not flexible, this method supplies a durable edge building and also has actually been preferred in the past by armed forces item designers. It is a costly remedy, nevertheless, because of the type of preparation called for and need to only be utilized after cautious factor to consider of the alternatives.
USE FLUOROPOLYMER COVERLAYER
Using fluoroplastics, such as Teflon ®, as coverlayers boosts tear resistance by virtue of the high tear resistance of the polymer itself. Fluoropolymers tend to stretch, rather than tear, which adds strength to the substratum. In high frequency PCB design, a fringe benefit of using fluoropolymer coverlayers is that the dielectric constant of the coverlayer is much reduced.
UTILIZE OF RADIUSED SLOTS
Making use of ports with ends that have a span to access relieved flex circuit features could likewise offer tear resistance. Typically, such attributes can effortlessly be provided for throughout the punching operation or various other flex PCB manufacturing process.
DRILLED HOLES AT CORNERS OR ENDS OF SLITS
Pierced or punched holes in edges or at the end of gain access to slits have actually been made use of effectively when flexible appendages must be placed close together. This technique takes full advantage of the use of flex PCB manufacturing material, yet the hole dimension chosen will impact tear resistance. If the holes are really small the general robustness will be decreased.
ARAMID FIBERS INSIDE CUT LINE
As an option to glass towel, aramid fibers transmitted with edges or along the whole rundown of the flex PCB provide a distinct technique to quit flexible circuits tearing. The thin polymer fibers are high-strength and pliable, minimally affecting versatility. Making use of aramid fibers is labor extensive and also needs to just be used with factor to consider of the price effect.
The option of approach to restrain or protect against tearing of the flex PCB is not an essential worry. What is extremely important is that the designer makes use of some ideal technique to secure versus tearing.
To sum up, all interior edges need to be provided with distance. It is important to repeat and also highlight that square or sharp interior edges are an invitation to difficulty and also ought to be studiously avoided. If the area of the edge is to be permanently bound to a rigid base, it is lesser, however still recommended, that a distance be made use of.