The customized dispensing valve scheme is suitable for most dispensing processes. We have achieved great success in the dispensing valve equipment industry based on the hydraulic control technology of China and South Korea, combined with advanced dispensing control technology in Europe and America. It has always been based on the forefront of automation technology and is committed to providing comprehensive automation solutions for large, medium, and small manufacturing enterprises.
The process defects that are prone to occur during product dispensing include: unqualified adhesive size, wire drawing, dipping, poor curing strength, and easy detachment. To solve these problems, it is necessary to study the technical parameters as a whole to find a solution to the problem.
1. The dispensing amount of the dispensing valve should be based on work experience, and the diameter of the dispensing point should be half of the product spacing. This ensures that there is sufficient glue to bond the components and avoid excessive glue. The distribution amount of the distribution valve is determined by the length of time. In practice, the allocation time should be selected based on production conditions (room temperature, glue viscosity, etc.).
2. Dosing pressure
The dispensing equipment provides a certain pressure to the needle (glue gun) to ensure the supply of glue. The pressure determines the glue supply and the glue flow rate. Excessive pressure can easily cause overflow and excessive glue; If the pressure is too low, intermittent dispensing and leakage may occur, leading to product defects. The pressure should be selected based on the properties of the adhesive and the working environment temperature. High ambient temperature will reduce viscosity and improve the fluidity of the adhesive. At this point, it is necessary to reduce the pressure value, and vice versa.
3. Needle size
In fact, the inner diameter of the needle should be about 1/2 of the diameter of the distribution point. During the dispensing process, the dispensing needle should be selected based on the product size. Different sizes of products should use different needles to ensure the quality of adhesive points and improve production efficiency.
4. The distance between the needle and the working surface is different. The distribution valve uses different needles, some of which have a certain degree of stopping. Before each work, calibrate the distance between the needle and the working surface, i.e. the z-axis height calibration.
5. Viscosity of glue
The viscosity of glue directly affects the quality of dispensing. If the viscosity is high, the adhesive point will become smaller, even wire drawing; If the viscosity is low, the adhesive point will increase, which may cause the product to stain. During the gluing process, choose a reasonable pressure and gluing speed for different viscosities of glue.
6. Glue temperature
In general, epoxy resin adhesive should be stored in a refrigerator at 0-5 ℃ and taken out half an hour in advance to ensure that the adhesive temperature is consistent with the working environment. The usage temperature of glue is 23 ℃~25 ℃; The ambient temperature has a significant impact on the viscosity of the adhesive. When the temperature decreases, the viscosity increases and the adhesive flow rate correspondingly decreases, making it easier for wire drawing to occur. When other conditions are the same, a temperature difference of 5 ℃ in the environment will result in a 50% change in adhesive production, so the environmental temperature should be controlled. At the same time, the ambient temperature should also be ensured. If the temperature is too high, the adhesive point is prone to drying and affects adhesion.
7. The curing temperature curve is provided by the general manufacturer for the curing of adhesive. In practice, curing should be carried out at a higher temperature as much as possible to ensure that the cured adhesive has sufficient strength.
8. foam
The glue should not have bubbles. Small bubbles can cause many products to lack glue; Every time the rubber hose is replaced, the air at the connection should be emptied to prevent it from becoming empty