Effect of temperature on viscosity

Temperature is the key factor of adhesive viscosity. According to our experimental center of the test data shows that: improve the temperature of 7 DEG C, viscosity drops out of the original 40%. In production when the viscosity drops, means that the needle point out the adhesive weight increased, while PCB glue point height is decreased, so the dispensing of the ambient temperature is constant, generally maintained at 25 degrees Celsius, to ensure an optimal dot profile.

The pressure on the viscosity effect

Coating process for pressure, pressure increased mean glue through the syringe outlet nozzle of the speed increasing, that is to say, the shear rate increased, usually in the production of the dispensing pressure control in 5bar ( 1bar = 1kPa ), usually located in a central value 3.0-3.5bar, high pressure due to shear D rate increase, so that the needle hair caused by heat, patch properties variation.

In time on viscosity

Time effect of key is adhesive to save time, assuming patch glue over the period of preservation, viscosity will rise. This belongs to the time of the glue viscosity indirect effects. But in the injection dispensing process it can affect the amount of glue, time grows, the glue quantity big.

Thus the effect of patch glue viscosity variation are the main factors to temperature and pressure, suggest that our customers in the actual production should pay special attention to these two factors change.