Dispensing Valve Seals For Thermal Paste And Particle-Filled Slurry
2026-09-05
Thermal paste, conductive adhesive, underfill media, and other particle-filled slurries often use screw valve structures in dispensing processes. Unlike high-frequency reciprocating valve seals, screw valve seals may face continuous rotation, particle wear, slurry corrosion, and friction heat. Seal selection should therefore review material, structure, motion type, and media together.
Why particle-filled slurry increases wear
Hard particles in slurry can increase wear on the sealing contact surface. If the seal material does not have enough wear resistance, wear may accelerate, clearance may change, leakage risk may increase, or dispensing stability may be affected. Continuous rotation can also generate friction heat, making material stability and low-friction behavior more important.
Material directions
The handbook discusses UPE and filled PTFE as important material directions for screw valve seals. UPE can be reviewed for low friction and wear resistance. Filled PTFE can be reviewed when low friction, chemical-media resistance, and wear resistance need to be balanced. The handbook mentions FFKM for extreme chemical media, but DEF Seals public supply capability for FFKM should be confirmed before it is published as an offering.
Energizer direction
When screw valve temperature and pressure are relatively mild, O-ring energizers may be evaluated based on cost, maintenance, and media compatibility. When stability, media compatibility, or rotary sealing structure becomes more demanding, metal spring energizers may also be reviewed. Spring material can be discussed around SUS304 or SUS316 according to corrosion level.
RFQ checklist
Buyers should provide slurry type, particle condition, particle characteristics if available, screw valve structure, rotation speed, pressure, temperature, sealing position drawing, shaft-end dimensions, old samples, target quantity, and sampling requirement. DEF Seals can discuss custom material direction and sealing structure based on drawings, samples, and operating conditions.
FAQ
Q: What problems are common in particle-filled slurry dispensing valve seals?
A: Common risks include faster wear, higher friction, media compatibility issues, sealing-clearance change, and leakage. The root cause should be reviewed by valve structure and media condition.
Q: How should UPE and filled PTFE be compared?
A: UPE is often reviewed for low friction and wear resistance. Filled PTFE is often reviewed for low friction, chemical-media resistance, and wear-resistance balance. Actual selection depends on particles, temperature, pressure, media, and structure.
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