Air-Jet Valve Bodies

Air-jet valve bodies are designed for standard bore diameters of ø8mm, ø10mm, ø12mm, and ø16mm. The bore must be machined to H7 tolerance (e.g., +0.015/0 for ø10mm) with a surface finish of Ra ≤ 1.6μm for the O-ring sealing surface. The valve body is press-fit or secured by a retaining ring at the cavity side of the mold plate. Installation depth (seat depth) varies by model — typically 15–25mm. The bore can be produced by standard drilling and reaming, no special tooling required. For retrofit installations, the existing ejector pin bore can usually be enlarged to accept the valve body.

Standard air-jet valves with Viton (FKM) O-ring seals are rated for continuous operation up to 200°C mold temperature. For higher temperatures, Kalrez (FFKM) seal kits extend the operating range to 300°C. The valve body itself (hardened tool steel) can withstand temperatures well above 300°C — the seal material is the limiting factor. For ultra-high-temperature resins (PEEK, PPS) processed above 300°C, metal-to-metal sealed valve designs are available as special orders. Note: at elevated temperatures, the compressed air supply must be filtered and dried to prevent moisture condensation inside the valve, which can cause corrosion and seal degradation.

Yes — air-jet valves are particularly well-suited for textured surfaces because they provide zero-contact ejection. The air blast breaks the vacuum lock between the textured cavity surface and the part without physically touching the part surface. This eliminates the glossy witness marks that mechanical ejector pins leave on textured surfaces. For heavily textured surfaces (VDI 30+), increase the air pressure to 0.5–0.8 MPa to overcome the increased surface adhesion. Position the valve at the center of the textured area or at the deepest vacuum-lock point. Multiple valves may be needed for large textured surfaces — space them 50–80mm apart for uniform air distribution.