A kind of processing method of rigid-flex board

Abstract

The invention relates to a method for processing a rigid-flexible printed circuit board (PCB). The method comprises the following steps: 1. pretreatment before compression: pre-cutting the compression surface of a PCB and removing the wastes of bonding sheets, wherein the pre-cutting treatment is to cut a crevice around a waste region of the PCB with laser, wherein the PCB is not cut off; 2. compression: compressing the PCB, the bonding sheets and a flexible printed circuit (FPC) board into a whole; 3. treatment after compression and before contour processing: drilling, depositing and platingcopper, making circuit and carrying out solder resist; and 4. contour processing: using a milling cutter to mill a groove around the waste region of the PCB, controlling the depth of the milling cutter to communicate the milled groove with the crevice and then removing the wastes of the PCB. The method is convenient for the removal of the wastes of the rigid PCB, and has the beneficial effects ofpreventing the milling cutter from directly milling the flexible PCB, greatly reducing the control requirement for milling cutter depth, reducing the requirement for PCB flatness, improving the processing quality of the product and saving the production cost.

Description

technical field [0001] The invention relates to the field of printed circuit boards, in particular to the field of manufacturing rigid-flex boards, in particular to a processing method for rigid-flex boards. Background technique [0002] Now to make soft and hard boards, there are generally two methods for removing the hard boards in the soft board area. One is to mill off the hard board waste (commonly known as "window") and then press and post-process. This processing method It is convenient and easy to operate, but the height difference at the window opening will seriously affect the quality of the subsequent process and cause waste of materials, such as the pressing process, one of the pressing accessories, silica gel, will produce indentations due to the height difference at the window opening, directly This leads to the scrapping of silica gel, resulting in a serious waste of materials; in the copper plating process, the adhesion of the copper at the window opening is ...

AI Technical Summary

Problems solved by technology

[0002] Now to make soft and hard boards, there are generally two methods for removing the hard boards in the soft board area. One is to mill off the hard board waste (commonly known as "window") and then press and post-process. This processing method It is convenient and easy to operate, but the height difference at the window opening will seriously affect the quality of the subsequent process and cause waste of materials, such as the pressing process, one of the pressing accessories, silica gel, will produce indentations due to the height difference at the window opening, directly This leads to the scrapping of silica gel, resulting in a serious waste of materials; in the copper plating process, the adhesion of the copper at the window opening is poor, and it is easy to fall off, resulting in a large amount of copper scraps that pollute the copper plating solution, resulting in "copper cylinder pollution"; in the circuit production process, The flat film sticking method of the automatic film laminating machine is not firm at the window opening, especially when it comes to the developing process, the developer can easily wash off the dry film at the window opening and cause a "film throwing" phenomenon; in addition, the solder mask process, the plane The printing method is also difficult to print the solder mask on the window

The above defects show that this hard board removal method has seriously affected the production of soft and hard boards; the second is to first complete the processes of pressing, drilling, copper plating, circuit production and solder masking, and finally perform shape processing to mill out the hard board. The board waste method, because the adhesive sheet is very thin, this method of hard board removal has a particularly high requirement for the depth control of the milling cutter. If the milling cutter is too deep, it will mill to the soft board. If the milling cutter is not deep enough, the hard board waste cannot be milled off. If the hard board waste is forcibly removed, a large number of burrs will be generated, and even the PCB substrate and the adhesive sheet will be partially separated and appear white, commonly known as "burst edge", which seriously affects the reliability of the product.

In addition, the second method also has high requirements on the flatness of the board, because the depth of the milling cutter is fixed, once there is a warped or concave part on the board, the milling cutter will mill the warped part to the soft board or the concave part. Part of the hard board waste cannot be milled, which seriously affects the production of soft and hard boards

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