Auto Filters Precise Proportioning and Automatic Foaming Process of Air Filter PU Adhesive

The performance of PU glue air filters largely depends on the precise batching and foaming control technology in the production process. Qualified automotive filter PU glue adopts a professional two-component system, including component A (polyether foaming agent) and component B (liquefied MDI curing agent). The factory strictly controls the mixing ratio within the industrial standard range, ensuring balanced foaming density, moderate hardness, and no brittle cracking or excessive softening. Improper proportioning will lead to unstable foaming, hollow frame, insufficient adhesion, or easy deformation of the finished filter.

In the automated production workshop, professional CNC PU glue injection machines are used for fully automatic stirring, metering, and injection. The equipment precisely controls the glue output speed and injection pressure to ensure uniform glue filling in each mold cavity. After entering the high-precision mold, the liquid PU material undergoes physical foaming and chemical cross-linking reactions at a constant temperature, expanding steadily to fill the entire mold space. This process eliminates manual errors and ensures consistent frame density and thickness for every batch of products.

After injection and foaming, the filter elements enter a constant-temperature curing area for staged standing and shaping. Slow molecular solidification prevents internal stress concentration of the PU frame. The whole automated proportioning and foaming process ensures that the PU frame has uniform texture, strong adhesion with filter paper, and stable overall structure. It effectively avoids common defective problems such as missing glue, glue overflow, hollow foaming, and frame warping in manual production, greatly improving the qualification rate and batch consistency of finished filters.