Overcoming the Dual-Valve Synchronized Dispensing Challenge: A Comprehensive Record of On-Site Problem Analysis and Optimization Solutions

 In today’s rapidly advancing industrial automation, high-precision dispensing processes have become indispensable in fields such as 3C electronics and semiconductor packaging. However, when traditional dispensing systems face increasingly complex products and process requirements, a series of challenges emerge. This article aims to provide an in-depth analysis of five core problems encountered during a real-world on-site service case involving dual-valve synchronized dispensing equipment, along with proven solutions.

 

1.The Dilemma of Mechanical and Vision Calibration for Dual-Valve Synchronization

Problem Description: 

The dual valves used for synchronization are pneumatic, lacking control over angle and height, relying solely on manual visual alignment.

Pneumatic valves are cost-effective and responsive, but their inherent limitation is the lack of precise electronic control over angle and height. This leads to situations where, during collaborative dual-valve operations for parallel or complementary dispensing on the same product, the initial alignment depends entirely on the operator’s visual observation and manual adjustment, making it impossible to guarantee precision and repeatability.

 

Solution: Establish a standardized manual alignment process.
We developed a set of repeatable operating procedures:

Initial Positioning: Place the customer’s product on the dispensing platform fixture and bring the dispensing needle tips as close as the product as possible to minimize visual error.

Angle First: First, manually adjust the jetting angle of both valve bodies. It is essential to recognize that angle deviation directly causes distorted glue line trajectories or abnormal dot shapes, being the primary factor affecting dispensing quality.

Height Synchronization: After the angle is set, use glue dispensing valve 2 (with non-adjustable height) as the reference, and finely adjust the height of Valve 1 to ensure the lower end faces of both valve needles are at the same horizontal level.

Parallelism Verification: After completing the above mechanical adjustments, perform a test dispensing cycle (with air pressure or actual adhesive) and observe the landing points. Make fine adjustments again to ensure the parallelism of the adhesive discharge paths from both valves.

This process transforms reliance on individual “craftsmanship” into a standardized “process,” significantly improving debugging efficiency and consistency.

1.Prevention and Handling of Air Bubbles in Adhesive

Problem Description: After setting the parameters, dispensing works normally, but it’s unpredictable how long a cartridge of adhesive will last before bubbles appear.

Air bubbles in the adhesive are the “silent killers” of the dispensing process. They can cause unstable adhesive flow, inaccurate adhesive volume, breaks in the adhesive bead, and even affect product sealing and electrical performance. Especially in large-capacity (e.g., 300cc) cartridges, under continuous use and heating conditions, trace moisture or air in the adhesive expands when heated, and the negative pressure zone at the rear of the cartridge can easily lead to bubble formation.

Solution: Subdivision, Deaeration, and Active Purging.

Physical Subdivision: Divide the large 300cc packaging of adhesive into several smaller capacity tubes. This greatly reduces the exposure time of a single tube on the equipment, minimizing the opportunity for bubble generation at the source.

Vacuum Deaeration: Perform vacuum deaeration treatment on the subdivided adhesive. This is the most effective method for removing existing bubbles.

Warm-up Purging: Because the adhesive heating function is enabled, after replacing a new adhesive tube or restarting the equipment after a period of shutdown, the internal state of the adhesive is unstable due to temperature changes and settling. At this point, it is strictly forbidden to start production directly. The “Purge” operation must be performed first for 1-2 minutes to expel potentially unstable adhesive—with uneven temperature or containing bubbles—from the lines and valve body. Only begin production after the adhesive flow is stable and smooth.

https://secondintelligent.com/industry-news/overcoming-the-dual-valve-synchronized-dispensing-challenge/