Pcb factory: brief analysis of SMT patch red glue process

Pcb factory: brief analysis of SMT patch red glue process

1、 What is red glue? Red glue is a kind of polydilute compound, which is different from solder paste in that it will solidify after being heated, and its freezing point temperature is 150 ℃. At this time, red glue starts to directly change from paste to solid. 2、 The properties of red glue Red glue has viscosity, fluidity, temperature characteristics, wetting characteristics, etc. According to this characteristic of red glue, the purpose of using red glue in production is to make the parts stick firmly on the PCB surface to prevent them from falling. 3、 Use of red glue (1) To maintain the quality of patch glue, please store it in the refrigerator (5 ± 3 ℃);

1、 What is red glue?

Red glue is a kind of polydilute compound, which is different from solder paste in that it will solidify after being heated, and its freezing point temperature is 150 ℃. At this time, red glue starts to directly change from paste to solid.

2、 Properties of red gum

Red gum has viscosity fluidity, temperature characteristics, wetting characteristics, etc. According to this characteristic of red glue, the purpose of using red glue in production is to make the parts stick firmly on the PCB surface to prevent them from falling.

3、 Use of red glue

(1) To maintain the quality of the patch adhesive, please store it in the refrigerator (5 ± 3 ℃);

(2) Before taking it out of the refrigerator for use, it should be kept at room temperature for 2-3 hours;

(3) Toluene or ethyl acetate can be used to clean the hose.

Glue dispensing:

(1) Adding a back stopper in the dispensing tube can obtain a more stable dispensing amount;

(2) The recommended dispensing temperature is 30-35 ℃;

(3) When subpackaging the rubber hoses, please use a special glue subpackaging machine for subpackaging to prevent bubbles from mixing in the glue. Glue scraping: the recommended glue scraping temperature is 30-35 ℃.

Note: After the red glue is removed from the cold storage environment, it cannot be opened for use until it reaches the room temperature. In order to avoid polluting the original product, any used patch adhesive shall not be returned to the original package.

4、 Process mode of red glue:

1. Printing method: the steel mesh engraving hole shall be based on the type of the part, and the thickness of the base material shall be 0.15 mm.

2. Dispensing method: compressed air is used to apply red glue to the substrate through the dispensing port. Dispensing has flexible functions.

5、 Typical curing conditions of red glue

1. More than 120 seconds after the PCB surface temperature reaches 150 ℃, or more than 150 seconds after reaching 120 ℃.

2. The higher the curing temperature and the longer the curing time, the higher the bonding strength can be obtained. The temperature actually added to the adhesive will vary depending on the material and size of the components installed on the PCB. Therefore, please find the most suitable curing conditions according to the actual production situation.

6、 Storage of red glue

1. In order to maximize the performance of the adhesive, it is necessary to store it in the refrigerator (2-5 ℃).

2. Warranty period: 6 months.

7、 Management of red glue

Due to its viscosity, fluidity, wetting and other characteristics affected by temperature, red glue should have certain use conditions and standardized management.

1. The red glue shall be stored in a refrigerator at 2~8 ℃ to prevent its characteristics from being affected by temperature changes.

The red glue shall be heated for 4 hours at room temperature, and used in the first in first out order.

3. For dispensing operation, the red glue in the rubber tube shall be de bubbled, and the red glue that is not used up at one time shall be put back into the refrigerator for storage. Old glue and new glue cannot be mixed.

4. This product should not be used in pure oxygen or oxygen enriched systems. It cannot be used as the sealing material of chlorine or other strong oxidizing substances.

8、 Precautions

1. Before use, avoid contamination. The uncured adhesive on the circuit board can be wiped off with isopropyl alcohol. In order to avoid polluting the unused glue solution, do not put any glue back into the original packaging container.

2. For people with allergic constitution, direct contact with the skin may sometimes cause skin allergy, so please pay attention.

3. In case of accidental contact with skin, please wash it immediately with soapy water.

4. When entering the eyes, please wash them with clean water as soon as possible and accept the doctor's inspection immediately.

5. It is non flammable (ignition point higher than 100 ℃). If it burns, put it out with dry powder, foam or carbon dioxide. During incineration, toxic gases, such as carbon oxides, will be generated. Avoid inhalation.

6. For a small amount of leakage, wipe it with a paper towel and put it in a container for disposal. Clean the leakage thoroughly with soap water or detergent. Avoid material entering drains or sewers.

Circuit board manufacturers and circuit board designers will explain the SMT patch red glue process.