Points to note in the process of dispensing

In the process of product gluing, the defects are as follows: unqualified glue point size, wire drawing, glue impregnation, poor curing strength and easy to fall off, etc. To solve these problems, it is necessary to study the technical parameters as a whole in order to find a solution.

In the process of product gluing, the defects are as follows: unqualified glue point size, wire drawing, glue impregnation, poor curing strength and easy to fall off, etc. To solve these problems, it is necessary to study the technical parameters as a whole in order to find a solution.

1. The amount of glue

According to work experience, the diameter of glue point should be half of the product spacing. This ensures that there is enough glue to hold the components together without too much glue. The amount of point glue depends on the length of time, the actual production should be based on the situation (room temperature, glue viscosity, etc.) select point glue time.

2. Gluing pressureThe dispensing equipment provides a certain pressure to the needle (glue) to ensure the supply of glue. The pressure determines the amount of glue and the speed of glue flow. Too much pressure is easy to cause glue overflow, glue amount is too much; If the pressure is too small, there will be gum discontinuity and leakage points, resulting in product defects. Pressure should be selected according to glue property and working environment temperature. High ambient temperature will make the glue viscosity smaller, fluidity becomes better, then need to reduce the pressure value, and vice versa.

3. Needle size

In practice, the inner diameter of the needle should be about 1/2 of the diameter of the gluing point. In the process of gluing, the needle should be selected according to the size of the product. Different needles should be selected for products with different sizes, which can not only ensure the quality of glue point, but also improve the production efficiency.

4. Distance between needle and working face

Different dispensers use different needles, some of which have a certain degree of stop. Before each work, the distance between needle and working face should be calibrated, that is, z-axis height calibration.

5. Viscosity of glue

The viscosity of glue directly affects the quality of glue. Large viscosity, glue point will become smaller, or even drawing; Small viscosity, glue point will become larger, and then may infiltrate the product. During the gluing process, select reasonable pressure and gluing speed for different viscosity glues.

6. Glue temperature

Generally, epoxy resin glue should be kept in a refrigerator from 0 ℃ to 5℃, and it should be taken out half an hour before use, so that the glue temperature is consistent with the working environment. The temperature of glue should be 23℃ ~ 25℃; The ambient temperature has a great influence on the viscosity of the glue. If the temperature decreases, the viscosity increases, and the flow rate decreases accordingly, it is more likely to appear the drawing phenomenon. Under the same other conditions, the difference of ambient temperature by 5℃ will result in a 50% change in the amount of glue produced. Therefore, the ambient temperature should be controlled. At the same time, the environmental temperature should also be guaranteed, too high temperature glue point easy to dry, affecting the adhesion.

7. Curing temperature curve

For the curing of glue, the general manufacturer has given the temperature curve. In practice should be as high as possible to cure the temperature, so that the glue after curing enough strength.

8, bubble

The glue must not bubble. A small bubble can cause many products to have no glue; When replacing the hose midway, empty the air at the connection to prevent empty punching.

9. Fluids that require special Settings

Instant adhesive: safe piston and Teflon lined metal needles are used for water-based instant adhesive, tapered oblique needles are used for thick instant adhesive, PP needles are used for flexible instant adhesive.

UV glue: use amber needle, white piston and oblique needle (UV blocking). If other kinds of needles are used, please make a needle with UV blocking.

Light curing adhesive: use black opaque syringe to avoid exposure to light. Anaerobic adhesive: 10CC syringe and white PE universal piston.

Sealant and paste fluid: if the use of white piston rebound serious, please use a safe type of live, use oblique needle.