/Several methods of SMT dispenser spot coating technology
There are three methods for the commonly used dispenser dispensing technique depending on the pressure application method.
(1) Time pressure method. This method was first used in SMT. It controls the time and pressure to obtain a predetermined amount of glue and the diameter of the glue dot. Usually, the amount of coating increases with the pressure and time. Due to its wide use in the use of disposable syringes and the need for cleaning, the equipment investment is relatively small. The disadvantage is that the coating speed is low, and the small glue amount of the micro-components is poorly coated and even difficult to realize.
(2) Archimedes bolt method. This method uses spin pump technology for coating with high repeatability and can be used for the application of the most difficult-to-apply patch adhesive. It requires more cleaning than the time pressure method, and the equipment investment is larger.
(3) Piston positive displacement pump method. This method uses a closed-loop dispenser that relies on matched pistons and cylinders to work. Since the volume of the cylinder determines the amount of glue applied, a consistent amount of glue and shape can be obtained, which is usually faster than the first two methods. However, its cleaning time is longer than the time pressure method, and equipment investment is also large.
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