Comprehensive comparison of pneumatic jet valves, piezoelectric jet valves, and screw valves: Glue selection - Compatibility guide
The
Visual Dispensing Machine of WELDO is a key equipment for many factories in the production of refrigerator stickers, key chains, badge gifts, accessories, hair clips, etc. This equipment offers various configurations for customers to choose from. Selecting the correct and suitable VISUAL DISPENSING MACHINE and glue for the production of your factory can help customers avoid common problems such as wire drawing, trailing, glue leakage, uneven glue dots, and needle blockage in the products, thereby improving the yield rate of the production line and reducing the loss of glue and labor debugging costs.
The dispensing valve of WELDO is equipped with four types: pneumatic jet valve, piezoelectric jet valve, screw valve, and precision dispensing valve. These four types of valve bodies have completely different driving methods, glue output principles, compatibility with glue viscosity, dispensing accuracy, and procurement and maintenance costs. This article will analyze these four dispensing valves to help customers accurately select the machine suitable for their factory's production.
Pneumatic Jet Valve
The pneumatic jet valve operates by using compressed air to drive the striker inside the valve body to move. The striker's return motion then releases the glue in the gap, spraying it from the nozzle in a regular frequency without touching the product.
With the VISUAL DISPENSING MACHINE using this pneumatic jet valve, there is no need to worry about scratching the product because it uses pneumatic non-contact glue spraying, eliminating the need for Z-axis height adjustment.
This valve body has moderate procurement cost and maintenance cost.
The valve body is equipped with a heating block, featuring excellent high-temperature resistance, and can easily handle products with high viscosity during use. The wear parts are durable, and most are made of tungsten steel.
The failure rate is low for large-scale continuous production, with extremely high cost-effectiveness, making it suitable for factories with limited budgets. It is very cost-effective.
It is suitable for the production of products using hot melt glue, epoxy resin, silicone, paint and varnish, etc.
However, this pneumatic jet valve needs to be used together with an air compressor and a stable pressure source. If the air pressure is unstable, it is prone to uneven glue application; the response speed and precision of the pneumatic jet valve are much lower than those of the piezoelectric jet valve, and it cannot perform fine and precise glue application.
Piezoelectric Jet Valve
The piezoelectric jet valve uses piezoelectric ceramic to drive the glue technology. When the piezoelectric stack in the valve body undergoes mechanical deformation under the voltage switching, it uses the lever principle to drive the striker to move up and down, forming piston movement. The striker impacts the nozzle during the piston movement, thereby causing the fluid to be ejected.
The entire process does not require auxiliary compressed air, completely eliminating the outgassing error caused by compressed air. The entire process is non-contact and remote airless dispensing, with a fast response speed and stable production unaffected by the air source. The operation is quiet during operation and suitable for the operation of precision products.
The valve body of the VISUAL DISPENSING MACHINE using the piezoelectric jet valve adopts a rapid upper-end correction method. Through adjustment using the scale screw at the upper end of the valve body to adjust the height of the striker, the alignment of the nozzle and the striker is corrected.
The purchase cost and maintenance cost of this valve body are relatively high. The core component of the piezoelectric ceramic has poor heat resistance, and there is a limit on the number of operations. After more than 10,000 operations, the electrical properties of the ceramic decrease; the piezoelectric striker cannot be forcibly disassembled. Due to the ceramic core being more affected by the operating environment, it is necessary to maintain a clean operating environment without obvious visible particles or debris, and keep it dry.
Screw valve
The screw valve precisely controls the rotation speed and forward and reverse rotation time of the screw through a servo motor. The valve body adopts a rotor and stator combined structure. In the closed space, the fluid is conveyed forward by the rotation of the rotor. When the rotor continuously rotates in the stator cavity, due to the effect of pressure, it moves smoothly and uniformly from the feed end to the discharge end of the valve, thus completing the stable transportation of the fluid.
VISUAL DISPENSING MACHINE with screw valve glue compatibility is extremely strong. By using the online mixing glue method, it is very suitable for quick-drying reactive glue, directly compatible with two-component AB glue ratio DISPENSING.
This valve body is used in combination with WELDO's 741 precision dispensing valve. It cannot achieve remote spraying; it must contact the workpiece for dispensing. It needs to be coordinated with the Z-axis lifting movement. The rotor inside the piston is a wear-prone part. Long-term use will cause wear, and it needs to be replaced regularly.
After each work is completed, the valve body needs to be cleaned. If the glue solidifies in the valve body, it will cause the inability to discharge normally. Mixing different adhesives is prone to produce lumps and block the valve body.
The viscosity of the glue is the first criterion for selection in the DISPENSING MACHINE.
1. For some low-viscosity glues, such as UV glue, water-based glue, and glue for filling the bottom of chips, the best choice is the piezoelectric jetting valve. It can precisely and accurately position and apply the glue without deviation or spread.
2. For medium-viscosity glues, approximately ranging from 10,000 to 100,000 cps, like epoxy resin, AB glue, silicone, and paint, for mass production with high speed, the pneumatic jetting valve is the best choice. For fine line drawing and continuous glue application, the piezoelectric valve should be selected, ensuring worry-free rapid production.
3. For high-viscosity glues, approximately ranging from 100,000 cps, the screw valve or pneumatic jetting valve can be chosen for stable glue output and precise quantitative accuracy.
If you are unsure about which type of valve body to choose, please feel free to contact us. We will customize a unique visual dispensing solution specifically for you based on our own glue parameters and product dimensions.
