Before using dispensing machine, precise dispensing effect needs to be achieved. First of all, we need to know which parameters are constant and which parameters are variables. This paper discusses the knowledge of dispensing parameters constant variables.

 

331 automatic glue dispensing machine

 

The parameters of glue dispenser, glue filling parameters, viscosity, distance between needle and circuit board, temperature stability, inner diameter of needle, rheological property, diameter of glue point, whether there are bubbles in glue, recovery height of Z axis of adhesion force (wet strength), glue uniformity, time and pressure are all controllable variables, which will be directly or indirectly shaded. Sound glue quality and product quality, which is also a variable part of the common dispensing parameters.

 

331 glue dispenser

 

First of all, we need to consider the effect of rheological properties on the automatic dispensing process. The rheological properties of the patch film decrease rapidly at high shear rate, but increase rapidly when shear stops. Good rheological properties can ensure that the adhesive of the patch flows out of the needle and forms a qualified adhesion on the substrate. Joint point, which should be paid attention to in the knowledge of constant variables of dispensing parameters.

 

Removal and Resuction Control Valve

 

Secondly, the influence of wet strength, because the wet strength of patch film is the strength of pre-curing adhesive, it can be used to fix components to resist the movement or vibration of circuit board. The distance between needle and circuit board and the inner diameter NID of needle is an important constant variable of dispensing parameters in production, if the distance ND between needle and base is not. Correctly, the operator will never get the correct dispensing results. With other parameters unchanged, the larger the ND, the smaller the diameter GD, the higher the height h, the smaller the ND, the larger the diameter GD, the lower the height h of the adhesive point, the distance between the needle and the substrate ND is calculated according to the diameter NID of the needle. The smaller the diameter of the needle is, the smaller the diameter of the needle will be. The distance between the needle and the plate becomes more important.