PCB Technical - PCB packaging methods and factors affecting appearance

One, PCB packaging method

1. Process destination

The process of "packaging" has received much attention in PCB circuit board factories, and it is generally not as good as the various steps in the process. The primary reason is that on the one hand, of course, it does not generate added value. On the other hand, Taiwan's manufacturing industry has not paid attention to it for a long time. Unmeasured benefits that product packaging can bring

2. Discussion on pre-packaging

The previous packaging method, see the table of expired shipping packaging methods, and details its deficiencies. Now there are still some small factories that use these methods to package.

The domestic PCB circuit board production capacity is expanding rapidly, and most of it is for export. Therefore, the competition is very fierce. Skill level and quality must be determined by customers, and the quality of packaging must be satisfied by customers. Electronic factories with a little planning now require PCB manufacturers to ship packaging. It is necessary to pay attention to the following matters, some of which are even direct Give the standard of shipping packaging.

1. Vacuum packaging is necessary

2. The number of boards per stack is too small depending on the size.

3. Standards for the tightness of each stack of PE film and the rules for the width of the margin

4. Standard requirements for PE film and AirBubbleSheet

5. Carton weight standard and others

6. Is there any special rules to put buffers in front of the board inside the carton?

7. The resistance rate standard after sealing

8. Quantities limit per box

The current domestic vacuum skin packaging (VacuumSkinPackaging) is very different, the main difference is only the useful working area and the degree of automation.

3, vacuum tight packaging (VacuumSkinPackaging)

Operation Procedure

A. Preparation: Position the PE film, manually operate whether the mechanical action is normal, set the PE film heating temperature, vacuum time, etc.

B. Warehouse board: When the number of stacked boards is fixed, its height is also fixed. At this moment, you must consider how to stack it to maximize the output and save the data. The following are a few criteria:

a. The interval between each stack of boards depends on the standard (thickness) and (standard is 0.2m/m) of the PE film, using the principle of heating and softening and stretching, and the vacuum is sucked together, and the board is covered with the bubble cloth. The interval is generally at least twice the total thickness of each stack. If it is too large, the data will be spoiled; if it is too small, it will be more difficult to cut and it is easy to fall from the sticking place, or it may not stick at all.

B. The distance between the outermost board and the edge must also be at least twice the thickness of the board.

c. If the PANEL scale is not large, according to the above packaging method, it will waste information and manpower. If the quantity is large, it can also be similar to the flexible board packaging method to open the mold to make the container, and then make the PE film to shorten the packaging. There is another method, but It is necessary to seek the customer's consent to leave no space between each stack of boards, but separate them with cardboard, and take the appropriate stack. There are also cardboard or corrugated papers underneath.

C. Start: A. Press to start, and the heated PE film will be led down by the pressure frame to cover the countertop B. Then the bottom vacuum pump will suck in air and stick to the circuit board, and stick it with the bubble cloth. C. Wait. Remove the heater to cool it and raise the outer frame D. After blocking the PE film, pull open the chassis to cut the partition for each stack

D. Packing: If the customer specifies the packing method, it is necessary to follow the customer's packing standard; if the customer does not specify it, the packing standard in the factory must be established according to the principle of maintaining the board transportation process not to be damaged by external forces. Pay attention Matters mentioned earlier, especially the packing of exported products, must be paid special attention.

E. Other matters needing attention:

A. There are necessary information written outside the box, such as "oral wheat head", material number (P/N), version, period, quantity, important information, and MadeinTaiwan (if export).

b. Attach relevant quality certificates, such as slices, weldability statements, test records, and some test statements required by various customers, and place them in the method specified by the customer. The packaging is not a college knowledge, do it with your heart, and when It can save a lot of trouble that shouldn't happen.

2. Factors affecting the appearance of PCB circuit boards

1 Overview

With the rapid development of PCB circuit board manufacturing technology, users are now not only demanding the inherent quality of PCB circuit boards (intrinsic quality refers to hole resistance, copper foil thickness, continuity testing, solderability, etc.), but also The appearance of the PCB circuit board puts forward higher requirements, such as: the color of the ink should be uniform and free of impurities, and the surface of the copper layer should be free of foreign matter and oxidation points. The influence of the pre-screening treatment on the appearance quality is discussed below.

The main influences of the pretreatment of screen printing on the appearance of PCB circuit boards are: the copper under the ink is oxidized, and there is hard damage (obvious scratches on the copper layer or substrate) after the pretreatment. The color of the ink on the copper foil is uneven. The quality of the pre-treatment directly affects the appearance quality of the PCB circuit board, slightly causing rework, affecting the production schedule, delaying the delivery date, and reducing the company's reputation; serious ones may also cause The board is scrapped. Finally, the company's "orders" are reduced, which directly affects the company's economic benefits.

In order to gradually reduce the loss caused by the pre-treatment and improve the company's competitiveness, it is necessary to strictly control the pre-treatment process.

2. Purpose and method of pre-processing

The final purpose of the pre-treatment is to make the copper surface free of oxides, grease and impurities, and also have a certain roughness. The board after the pre-treatment has a certain roughness. The board after the pre-treatment is tested with the Zero-Ion100A ion concentration test The instrument performs a cleanliness test to see the concentration of impurity particles on the treated board. The ion concentration is lower than 1.5μg/cm2, and the state of the copper layer surface is shown in Figure 1. It has a relatively uniform concave-convex structure and no oxidation points, so as to enhance the mechanical bonding force with the ink, and prevent blistering and large-area shedding, and at the same time, it does not affect the conductive performance of the PCB circuit board.

There are many ways of pretreatment. Now the main ones commonly used in the industry are the following: nylon brush scrubbing, chemical cleaning treatment, alumina/pumice powder injection, alumina/pumice powder plus nylon brush, chemical cleaning plus nylon brush.

3. The pre-treatment process and matters needing attention

According to the PCB company's own conditions, a large number of experiments have been carried out on the process flow, parameters and matters that should be paid attention to in the operation of the pretreatment, and the process flow and parameters have been optimized, which has played a very good effect.