FPC(Flexible Printed Circuit) refers to flexible printed circuit board, also known as flexible printed circuit board, flexible circuit board or flexible board. The circuit board has the advantages of high wiring density, light weight and thin thickness. Widely used in mobile phones, notebook computers, PDAs, digital camera, LCM and many other products. In recent years, PCB manufacturing process has developed rapidly, and the industry has put forward higher requirements for FPC, and precision PITCH is the main breakthrough direction of FPC in the future. The stability and refinement of the size have also led to the rise of the cost of FPC, and how to control the contradiction between the two has become the main breakthrough in the production process to control the growth and shrinkage of FPC materials. Here we give you a brief explanation on how to control and control the main points.

First, design

1. Line: Because FPC will expand due to temperature and pressure during ACF crimping, the expansion rate of crimping finger should be considered in the initial design of the line, and pre-compensation processing should be carried out;

2. Typesetting: The design products are evenly distributed in the entire typesetting as far as possible, the minimum interval between each two PCS products is maintained at more than 2MM, and the copper-free part and the porous dense part are staggered as far as possible, which are two important aspects affected by material growth and contraction in the subsequent manufacturing process.

3. Material selection: the adhesive covering film should not be thinner than the thickness of copper foil, so as to avoid the deformation of the product due to insufficient adhesive filling when pressing, and the thickness and distribution of the adhesive are the main culprits for the expansion and shrinkage of FPC materials. 4. In terms of process design, the covering film should cover all copper foil parts as far as possible, and it is not recommended to stick the covering film to avoid uneven force during pressing. The PI reinforcement and laminating surface adhesive above 5MIL should not be too large.

2. Material storage

I do not need to say more about the importance of material storage, need to be stored in strict accordance with the conditions provided by the material supplier, should be refrigerated, can not be careless.

Third, manufacturing

1. Drilling: It is best to add baking before drilling to reduce the expansion and contraction of the substrate during subsequent processing due to the high moisture content in the substrate.

2. Electroplating: should be made of short side splint, which can reduce the deformation caused by the water stress caused by the swing, the swing can be reduced as far as possible during electroplating to reduce the swing amplitude, the number of splint also has a certain relationship, the number of asymmetric splint, can be assisted by other side materials; When electroplating, the lower slot is charged to avoid sudden high current impact on the plate, so as not to cause adverse effects on plate electroplating.

3. Pressing: The traditional pressing machine is smaller than the fast press, the traditional press is constant temperature curing, the fast press is hot curing, so the change of the traditional press control glue to stabilize this, of course, the laminate plate is also a very important part.

4. Baking: For fast-pressure products, baking is a very important part, baking conditions must be achieved to make the glue completely cured, otherwise in the subsequent production or use of infinite trouble; The baking temperature curve is generally the first to gradually rise to the temperature of the glue is completely melted, and then continue at this temperature until the glue is completely cured, and then gradually cool down.

5. In the production process, try to maintain the stability of temperature and humidity in all stations, and the transfer between stations, especially those that need to be made out, the conditions of product storage need special attention.

Fourth, packaging

Of course, the completion of the product is not to say that everything is fine, to ensure that customers in the subsequent use of no problems, in the packaging, it is best to bake, the product in the manufacturing process of the substrate absorbed by the water drying, and then vacuum packaging, and guide customers how to save.

Therefore, to ensure the stability of the quality of such products, from material preservation to process control to packaging to customer use must be carried out in strict accordance with specific requirements.