Flexible Printed Circuit Board Applications (4)

The CCD positioning punching machine punches the positioning holes required for the post-work station.

4.8.1. Punching Notes

Irreversible
Is the hole number correct?
Hole can not be flashed

4.9. Tin plating

The surface treatment is performed with a finger Pad of the CVL opening position with electroplated tin lead.

4.9.1. Tin Lead Precautions

Whether clamping plate is clamped
After electroplating appearance (can not be white fog coke black exposed copper pinhole)
Film thickness test according to specifications on the transfer order
Adhesion test with 3M 600 tape test
Solderability Test with Tin Furnace 280 10 seconds Tin Solder Tin area must exceed 95%

4.10. Horizontal spray tin

The surface of the finger and pad of the CVL opening position is treated with a horizontal spray of tin. The water absorbed by the PI is first removed by baking, then the flux (Flux) is sprayed, washed, and dried.

4.10.1. Precautions for Spraying Tin

Is baking time sufficient
Guide paste method
Whether washing is clean and there is no Flux residue
Spray tin appearance (can not have stripping copper penetrant exposed copper and tin surface uneven tin slag crush, etc.)

4.11. Printing

Generally speaking, it is printed text. Silver paste is usually used for shielding. Silver paste must be printed and then soldered for protection.

4.11.1. Printing Precautions

Ink viscosity
Printing direction (front/back/front/back direction) Divides the front and back sides according to the printing film coding principle. The front and rear directions are distinguished by the printing alignment mark and the arrow mark.
Printing position
Is the printing table clean?
Is the stencil cleaner?
Is Print DateCode correct?
Printed appearance (inset open text, etc.)
Post-bake adhesion test with 3M 600 tape test

4.12. Stamping

Generally, Hard Die is used for punching the soft board. The precision is better. The steel rule die is generally used for sample preparation, or it is generally used for backing rubber, PI/PET reinforcing sheet, and other precision requirements are not required. High fittings are used for punching, and they are also used for strips. When the product length is longer, the steel mold can be designed two-stage punching type to avoid bias due to material expansion and contraction. At this time, symmetrical mold typesetting is required. Only one set of steel molds can be used, otherwise two sets of steel molds must be opened. .

4.12.1. Precautions

Finger position
Indentation
Flash
Adhesive / reinforcing sheet direction

4.13. Electrical test is performed on a single board or punched single pcs. Usually only Open/Short/insulation resistance is measured. If there is a resistor/capacitor on the finished product, the ICT test is required. When the whole board is measured, it is divided into full test. And only to measure the short circuit (open circuit to visually check the finger or Pad is plated with tin and lead to distinguish) two.

4.13.1. Principle of Whole Board Short Circuit Test

When the line is a simple cable, the entire plate can be measured by electroplating line design to save electricity measurement time. The principle is to pull out the plating line using single or double jumper cables. When any adjacent line is short-circuited, Can be measured, but the fingers can not be tin-lead plating, as shown in the figure.

Dashed line indicates molding edge

4.13.2. Electrical Measurement Precautions

On resistance Impedance Insulation Impedance High voltage and other conditions are correct
Test number is correct
Test file name is correct
Check code is correct
Whether the electroplating line is cut off when measuring the whole board
Is the foolproof device turned on?
Whether bad products are separated

Source: SMT Information Network