Spray technology is to spray glue from the nozzle at a very fast speed, relying on the momentum of the glue to make the glue out of the nozzle. Each spray produces a certain amount of glue. Different from the dispensing syringe, the nozzle does not form a continuous underfill flow, instead, it sprays more than 200 accurately measured glue points per second. With the horizontal movement of the nozzle, the glue point can form various required lines and patterns, such as solid line, dotted line and other different graphics. Each injection is precisely controlled, and the minimum diameter of glue points formed by one injection can reach 0.33mm, which is very important for the application of patch adhesive and other occasions that need to accurately control the area.

Syringe dispensing is being replaced by spray dispensing. The so-called jetting is a new technology, which uses nozzle type instead of syringe to solve many problems. Jetting nozzle can be used for dispensing above the device that needs to be underfilled without reaching the position below its top surface. Jetting nozzle moves in X and Y direction over the whole circuit board without vertical movement.

The LED market also benefits from glue spraying technology. The spray process can spray a wide range of optical materials, including silicon adhesive, UV curable phosphorus doped conductive adhesive and so on. It can carry out precise dispensing and glue quantity control in high-speed dispensing. The precision of glue spraying can improve the yield of high-power LED devices with high value. It can be used in white light production, fluorescent powder and mixed glue dispensing to improve the consistency.

At present, the common injection frequency is 100 Hz to 200 Hz, but it will soon reach 1000 Hz. In the concept of UV LED, there are different views and opinions. It's just like that there are several kinds of UV point light sources. I believe that professionals are familiar with them, and so is the light curing machine. There are several differences between spray dispensing and needle dispensing. When the glue is ejected from the nozzle, the glue is separated from the nozzle before contacting the substrate. Each glue point is sprayed onto the substrate to form points, lines and patterns. During the movement of dispensing position, the dispensing head does not move in z-axis direction, which saves a lot of time. When the needle is dispensing, the manipulator moves on the X, y and Z axes. The glue flows out of the needle and contacts the substrate. The glue is separated from the needle by gravity and the surface tension of the substrate. After each dispensing, there is an obvious movement along the Z axis, and then move to the next dispensing position.

Source: China UV lamp net