3 Notices for Layout Double-Side BGA for FPC

Layout double-side BGA for FPC is used in some products, but since the complexity of manufacturing process and maintainability need to be taken into consideration, the designers need to pay attention in followings:

1. Do not overlap when layout double-side BGA and a certain of distance is required left. The reason why to do that as it is difficult to repair if there is poor BGA on one of sides.

2. In order to prevent the BGA on the bottom from melting during the second time reflowing, it is required to decrease the bottom temperature in the second time reflowing. It is better to decrease the bottom temperature lower than to the melting temperature of solder joints to ensure that the solder joints do not melt again. What’s more, you can fix the bottom BGA with jig.

4 ways to increase deformation resistance for flex circuits:

1. The stress resistance of BGA can be strengthened by a supporting iron frame around it.

2. The stress resistance of BGA can be strengthened by gluing around it or on the corresponding back of flexible PCB.

3. If you aim at protecting the BGA, then you are able to add screw to fix the other parts around BGA. In this way, the other parts around BGA won’t deform easily.

4. Strengthening the outer shell of flex circuits to avoid its deformation affecting the inner circuit.

As the premier expert in flexible circuit fabrication, Best Technology has a team which always striding for high quality flex circuits and services. If you would like to know more about Best Technology, please give us a call at 0755-29091601 or view our website: https://www.bestfpc.com/

How to Paste Coverlay on FPC?

If you have ever learned something about flex circuits, you would know there is a layer of coverlay on it. Pasting coverlay on flexible circuit is to prevent it from the damages of dust, moisture and so on. Meanwhile, it also plays an role in insulation. We have learned something about the benefits of pasting coverlay on flex circuits, but how to paste the coverlay? Let’s take a look.
To begin with, we need to prepare the coverlay material, checking whether the soldering iron has power, cleaning the residue of soldering iron and the dust-free paper.

The procedures of pasting the coverlay on FPC:

  1. Checking whether the coverlay and film have problems, including missing punching, missing drilling, too large burr on the coverlay etc.. After that, clean the dust on the surface of coverlay with packaging cleaner.
  2. Cleaning the worktable and putting the coverlay, soldering iron and other tools in the right place.
  3. Checking whether there are oxidization, litter, dust etc. on the flex circuits to be pasted.
  4. Pasting the coverlay should follow the requirements of process and the MI data. It should be strictly follow the “C”marking line, pad or counterpoint hole when align.
  5. How to peel the coverlay off: putting the covelay on the optical desk, but please remember that the release film is facing up and the coverlay is facing down. After that, holding the coverlay then peeling off the release film slowly.
peeling the coverlay off

peeling the coverlay off

  1. Fixing the coverlay on FPCwith soldering iron after the coverlay is aligned with the “C” marking line of the flex circuit board and ensure it is correct, so that the coverlay can not deviate or peel off. However, please remember the soldering iron can not burn the products.
pasting coverlay on FPC

pasting coverlay on FPC

  1. Single-side lamination: after pasted the coverlay on FPC, it should be gone through the machine with temperature between 160°C-165°C. Next, until the board got cold, the release film should be peel off and carry out the single-side lamination and self-checking.

Notices:
1. It is necessary to wear rubber gloves to prevent the flexible printed circuit board from oxidization or dirty.

  1. It must be kept clean during pasting coverlay on FPCto prevent there are dirty residues on flex circuits.
  2. It is required to check whether the coverlay is broken, wrinkled, scratched, etc..
  3. Do not wear accessories to avoid scratching the board.
  4. It is necessary to confirm that the coverlay leave a little bit space for plating if the flex circuitsare tin or gold plating.
  5. The hand could not beyond the handle to avoid burning when holding the soldering iron.

Best Technology is the premier expert in the manufacture of electronic components, brings a unique combination of technology and quality that offers a competitive supply of flex circuits and rigid-flex circuits and other flexible circuit products. With high qualified engineers, we are able to help you find a FPC with high quality. To find out more, contact Best Technology at 0755-29091601 or check the website: https://www.bestfpc.com

The Keys in the Mobile Phone

With the development of smart phone, the mechanical key has been already eliminated from the stage. There is only the HOME key left on the front side of the phone. Even sometimes the HOME key is also out and there are only two keys left–volume key and power key. These two are usually used a FPC to save cost as well as space. The structure showing as below:

volume key & FPC

volume key & FPC

power key & FPC

power key & FPC

For the design of volume key and power key, there are two things required to considerate. On one hand, the position of the flex circuit. Since the flexible circuit is glued on the supported wall, three directions need to be limited if you would like to fix the FPC. As well, the designers still need to consider the installation position of the keys itself, which determines the basic structure of the keys.

On the other hand, the volume key and power key are moving parts. Therefore, taking the stroke of metal domes into account is necessary and as general rule the stroke is 0.3. In addition to hard contact mode, there is also a soft contact mode (P+R), which is to use rubber or TPU (Thermoplastic polyurethanes) for the part where the key is contact with the dome, so that the sound is softer.

key structure

key structure

Best Technology is the premier expert in the manufacture of electronic components, brings a unique combination of technology and quality that offers a competitive supply of flex circuits and rigid-flex circuits and other flexible circuit products. To find out more, contact Best Technology at 0755-29091601 or check the website: https://www.bestfpc.com/