ShenZhen Leap Electronic Co.,Ltd


how to fixing the flexible printed circuit

Author:Luwis zeng Date:7/24/2018 8:12:29 AM
 Before performing SMT, it is first necessary to accurately fix the FPC on the carrier board. It is important to note that the shorter the storage time between printing, placement and soldering, after the FPC is attached to the carrier, the better. The carrier plate has two types of positioning pins and no positioning pins. The carrier board without the positioning pin should be used together with the positioning template with the positioning pin. First, the carrier board is placed on the positioning pin of the template, so that the positioning pin is exposed through the positioning hole on the carrier board, and the FPC is placed one by one. The exposed locating pins are then taped and the carrier is separated from the FPC positioning template for printing, placement and soldering. A number of spring positioning pins with a length of about 1.5 mm have been fixed on the carrier plate with the positioning pins. The FPC can be directly placed on the spring positioning pins of the carrier plate and then fixed with tape. In the printing process, the spring positioning pin can be completely pressed into the carrier by the steel mesh without affecting the printing effect.

Method 1 (single-sided tape fixing): Fix the four sides of the FPC on the carrier board with a thin high-temperature single-sided tape. Do not allow the FPC to have offset and warp. The viscosity of the tape should be moderate. It must be easily peeled off after reflow and in FPC. There is no residual glue on it. If you use the automatic tape machine, you can quickly cut the length of the tape, which can significantly improve efficiency, save costs and avoid waste.

Method 2 (double-sided tape fixing): firstly attach the high-temperature double-sided tape to the carrier board, the effect is the same as that of the silica gel board, then paste the FPC into the carrier board, pay special attention to the viscosity of the tape should not be too high, otherwise it will peel off after reflow soldering. When it is easy to cause FPC tearing. After repeatedly passing the furnace, the viscosity of the double-sided tape will gradually become lower, and the viscosity is so low that it cannot be reliably fixed when the FPC is fixed. This station is a key station to prevent the FPC from being dirty, and it is necessary to wear a finger sleeve. Before the carrier board is reused, it needs to be properly cleaned. It can be scrubbed with a non-woven cloth cleaning agent or an anti-static dust roller to remove foreign matter such as surface dust and tin beads. Do not use too much force when handling FPC. FPC is fragile and prone to creases and breaks.

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