What may be the cause of the unstable glue output of the dispensing machine?
Glue-related factors
Glue viscosity changes:
Temperature influence: If the ambient temperature fluctuates greatly or the glue dispenser does not have effective glue temperature control measures, the glue viscosity will change with the temperature. For example, when the temperature drops, the viscosity of some glue increases, the fluidity becomes worse, and the glue output will decrease; when the temperature rises, the viscosity decreases, and the glue output may increase.
Ingredient differences: Different batches of glue, even if the model is the same, may have slight differences in the actual component ratio, resulting in inconsistent viscosity, which in turn affects the stability of the glue output. For example, the solvent volatilization degree in some glues is different, causing the glue to become thicker or thinner, and the glue output situation also changes accordingly.
There are bubbles in the glue: During the storage, preparation or addition of the glue to the glue dispenser cylinder, air is mixed in to form bubbles. When dispensing, the bubbles occupy the glue space and will be squeezed out with the glue from time to time, causing the actual amount of glue squeezed out each time to fluctuate, resulting in unstable glue output.
Equipment hardware
Unstable air pressure: For glue dispensers that use air pressure to drive glue, if the air pressure of the air source itself is unstable, or there are leaks or blockages in the air path, the pressure acting on the glue will fluctuate. For example, if the air path joint is loose and causes a slight leak, the air pressure will not reach the set value, affecting the stability of the glue output.
Needle problem:
Needle blockage: Impurities in the glue, dried glue blocks, etc. are easy to block the needle, making the channel for the glue to flow out narrower or even partially blocked, resulting in slower glue output and less glue output. The degree of blockage may change with the glue dispensing process, further causing the glue output to fluctuate.
Needle wear: After long-term use, the inner diameter of the needle will become larger or irregular due to wear, so that the flow rate of the glue through the needle is difficult to accurately control, destroying the stability of the glue output.
Pump body failure: If the dispensing machine uses a glue pump to deliver glue, problems such as gear wear (for gear pumps) and aging or damage of the pump tube (for peristaltic pumps) will affect the normal delivery efficiency and flow accuracy of the glue, making the amount of glue delivered to the dispensing head unstable.
Wear of moving parts: In the motion platform of the dispensing machine, parts such as lead screws, guide rails, and sliders will wear after long-term frequent operation, resulting in a decrease in the positioning accuracy of the dispensing head. For example, it was originally necessary to accurately position at a certain point for quantitative dispensing. Due to the wear of moving parts, the positioning deviation occurred, and the dispensing position was inaccurate, affecting the uniformity and stability of the overall glue output.
Control system
Irrational parameter settings:
Improper setting of glue output time: If the set glue output time is too long or too short, it does not match the actual glue viscosity, needle specifications, etc., which will cause the glue output to be inconsistent with expectations. In addition, when dispensing different products, if the glue output time parameters are not adjusted in time and accurately, the glue output will also fluctuate.
Incorrect pressure parameters: At the time of air pressure driving, the air pressure value is not set accurately, and it is not set reasonably according to the characteristics of the glue liquid and the needle condition, which will cause abnormal glue liquid extrusion pressure and unstable glue output.
Control program failure: The control program of the dispensing machine has loopholes, errors or electromagnetic interference, which may cause inaccurate control instructions for the glue output. For example, intermittent abnormal glue output instructions appear when the glue should be discharged at a uniform speed, causing the glue output to fluctuate.
External environmental factors
Vibration interference: If the dispensing machine is placed near a significant vibration source, such as large stamping equipment, motors that start and stop frequently, the vibration will affect the normal operation of the dispensing machine, destroy the position of the dispensing head and the stability of the glue liquid extrusion, and it is difficult to ensure the stability of the glue output.
Unstable power supply: When the power supply voltage fluctuates significantly, the working state of the dispensing machine's motor, controller and other electrical components will be affected, which will in turn affect the overall dispensing operation, which may cause unstable glue output.