Characteristics
- The micro-screw dispensing valve is specially designed for high-viscosity or micro-particle-dispensing materials (above 50,000 cps). It can meet the high precision requirements for wire drawing or dot-punching applications, and the micro-liter dispensing control can be easily achieved.
- With a dedicated controller, it has a reverse suckback function to reduce the drawing phenomenon during dispensing. Vacuum suction can avoid dripping when the machine is down
The improved screw and bushing design is easy to disassemble for easy cleaning and maintenance. Significantly reduces machine downtime. - Suitable for soft or hard particles such as solder paste, silver paste and COB vinyl. Screws and bushings with super-hard materials are also available to reduce wear.
- Reducing the glue residue space in the valve reduces glue loss and reduces the chance of bubble residue.
- The amount of glue spit is affected by the viscosity change and the needle plugging between the needle pressure dispensing and the plunger pump. It is a half-discharge type and can control the micro-dispense.
Principle of operation
- The screw type micro-dispensing valve uses a screw to rotate the sleeve to push the glue. When the viscosity of the rubber material is higher, the frictional resistance between the screw and the screw sleeve is higher, and the rubbering thrust generated at this time is also higher.
- The more the number of screw threads, the higher the pressure at which the glue is obtained by gradually pressurizing each screw. The material with high viscosity is not easy to use. The screw type valve uses 3-5 times larger than the air pressure.
- The deeper the depth of the thread of the screw thread means that the amount of glue contained in each tooth is also increased, so the amount of glue that can be brought out by each rotation of the screw should be increased. However, the frictional shear stress between the rubber material and the screw and the bushing is also reduced, so that the final dispensing pressure is also reduced.
- The screw type micro-dispensing valve gradually pressurizes the glue when the screw is rotated, so the glue supply pressure of the syringe only needs to press the rubber material into the screw and the sleeve.
- When the screw rotates and the glue is gradually pressurized, if the bubble contains air bubbles, the air will be compressed by pressure.
- Therefore, the air will collect due to the compression and will be concentrated toward the lower pressure inlet end. The air that cannot be collected toward the inlet end is eventually crushed by the rubber material due to the agitation of the screw. Therefore, the screw type dispensing valve does not break due to air bubbles when the cable is pulled out, and the rubber material is more uniformly mixed by the agitation of the screw.
- When the direction of the electrode is switched to reverse the motor, the screw reverses pulling the glue back.
- The pressure in the needle is released so that the glue does not emerge from the needle tube when the valve stops to be dispensed, and the early breakage reduces the drawing phenomenon.
