The working principle of a glue dispenser generally involves precisely controlling the distribution of glue onto designated positions of a workpiece by managing glue supply and dispensing parameters. There are different types of glue dispensers, but the common working principles include the following main steps or methods:
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Heating and Melting (For Hot Melt Glue Dispensers):
Solid hot melt glue (strips, particles, or blocks) is heated to a molten state using an electric heating element with precise temperature control to maintain the right fluidity without degrading the glue. The molten glue is then pressurized for dispensing. -
Pressurized Delivery:
The molten or liquid glue is pushed out by a delivery mechanism such as a gear pump, piston pump, or air pressure system through a nozzle or dispensing valve. Pressure can be adjusted based on glue viscosity and coating needs. Air pressure may be applied to a syringe or glue chamber to force the glue out in controlled amounts. -
Precise Control of Glue Amount and Position:
The dispenser controls the glue flow rate, dripping speed, and dispensing position electronically or pneumatically, often through computer or touch-screen interfaces. This allows for accurate and repeatable placement of glue dots or lines with high precision. -
Mechanical Dispensing Methods:
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Piston Method: A piston moves down in a cavity, pushing out a fixed volume of glue. The amount of glue is determined by the piston stroke distance and can be adjusted manually or by software.
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Time-Pressure Method: The glue amount is controlled by the time that air pressure is applied to the glue, controlling the size of the glue dot.
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Screw Pump Method: A screw pump delivers glue at a controlled flow rate for high-viscosity fluids, offering consistent dispensing volumes and speeds.
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Jet Dispensing: Similar to inkjet technology, glue is ejected in droplets by a needle that moves under controlled air pressure and spring forces, allowing for high-speed dot dispensing.
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Specialized Glue Dispensers (Double-Liquid Glue Dispensers):
For two-component glues (e.g., AB glue), separate barrels and metering pumps control the volume of each component. The glues are mixed in a mixing head with a stirring motor before dispensing. Cleaning systems use air pressure and rotation to rinse residual glue.
In essence, a glue dispenser works by converting glue into a controllable fluid form (heated or liquid), then using mechanical or pneumatic pressure to deliver precise amounts to specific locations, with electronic control systems managing the timing, volume, and position to ensure accuracy and efficiency in various industrial applications.
This principle enables automated, consistent, and high-speed glue application suitable for electronics assembly, circuit boards, automotive parts, medical devices, and more.