What are the five knowledge points of Automatic Dispenser Stand?

1. According to work experience, the diameter of the glue point should be half of the pad spacing, and the diameter of the glue point after pasting should be 1.5 times the diameter of the glue point. This ensures that there is enough glue to bond the components and prevents too much glue from dipping the pads.

2. Excessive dispensing pressure and back pressure can easily cause overflow and excess glue; if the pressure is too small, there will be intermittent dispensing and leakage, resulting in defects. The pressure should be selected according to the same quality of glue and working environment temperature. High ambient temperatures will reduce the viscosity of the glue and improve its flow. In this case, according to the knowledge points of the automatic glue dispenser, the supply of glue can be guaranteed by reducing the back pressure, and vice versa.

3. Actually, the inner diameter of the needle should be 1/2 the diameter of the glue dispensing point. During the dispensing process, the dispensing needle should be selected according to the size of the pad on the printed circuit board: if the pad size 0805 and 1206 are not different, the same needle can be selected, but different size pads should choose different needles, so that It can not only ensure the quality of glue points, but also improve production efficiency.

4. Different needles are used in automatic dispensing machines with different needle distances for printed circuit boards, and some needles have a certain stopping degree. The distance between the pins and the PCB should be calibrated at the start of each job, i.e. the Z-axis height calibration.

5. Glue temperature Generally epoxy glue should be stored in the refrigerator at 0-5℃. When using, it should be taken out half an hour in advance to make the glue fully meet the working temperature. The use temperature of the glue should be 23℃-25℃; the ambient temperature has a great influence on the viscosity of the glue. If the temperature is too low, the glue dot will become smaller and stringing will occur. A 5°C difference in ambient temperature will result in a 50% change in dispensed volume. Therefore, according to the knowledge points of the automatic glue dispenser, the ambient temperature should be controlled, and at the same time, the ambient temperature should be ensured, and the glue points with low humidity are easy to dry, which affects the adhesion.