Quartz Flange Ring Factories & Factory for Hanoi

For ultra-high vacuum applications (< 10⁻⁶ Torr) using fluoroelastomer O-rings (Viton or Kalrez), we recommend an optical fine-ground or lap-polished finish with Ra between 0.2 μm and 0.4 μm. An excessively polished, mirror-smooth face can sometimes cause elastomeric gasket sticking or creep under high compression, whereas a rough surface creates microscopic gas channels across the sealing boundary. Our planetary lapping produces a controlled cross-hatch pattern with flatness ≤ 0.005 mm.

Because the coefficient of thermal expansion of stainless steel (approx. 16 × 10⁻⁶ /°C) is roughly 30 times higher than that of fused quartz (0.55 × 10⁻⁶ /°C), direct rigid metal-to-quartz clamping causes cracking during thermal cycles. We recommend using stepped split-ring clamps with resilient PTFE/graphite buffer washers, spring-loaded Belleville washer assemblies on all bolts, and torquing fasteners in an alternating star pattern to no more than 2.5–4.0 Nm depending on flange thickness.

Quartz flange rings and industrial quartzware typically import into Vietnam under HS Code 7002.31.00 (Tubes of fused quartz or other fused silica) or HS Code 7017.10.00 (Laboratory, hygienic or pharmaceutical glassware of fused quartz or other fused silica). Vulra Quartz provides comprehensive commercial invoices, packing lists, Certificate of Origin (Form E for zero or preferential tariffs under ACFTA), and TÜV material conformity test reports for rapid customs release at Noi Bai International Airport or Lang Son border terminals.

Yes. Utilizing multi-axis CNC ultrasonic core drilling and diamond-milling equipment, we precision-machine circular O-ring retention dovetail grooves, bolt pass-through holes, alignment pin recesses, and optical viewing ports directly into fused quartz blanks. All drilled holes feature chamfered edges (≥ 0.5 mm × 45°) to eliminate sharp corner stress concentrations that could propagate micro-fractures under thermal loading.

Our packaging protocol is engineered specifically for cross-border transit: each flange is ultrasonic acid washed, heat-sealed in cleanroom-grade antistatic polyethylene wrapping, cushioned with high-density molded EPE foam suspension inserts inside a primary heavy-duty carton, and then packed within a shock-isolated, fumigated plywood export crate. Every crate features Tip-N-Tell drop sensors. In the rare event of transit damage, Vulra Quartz provides immediate, prioritized replacement remanufacturing.

For prototype and customized drawing orders, engineering review takes 12–24 hours, followed by CNC fabrication, annealing, and inspection within 7–10 business days. Expedited air shipping to Noi Bai Airport (HAN) takes approximately 24–48 hours, enabling total door-to-door delivery within 10–14 days. Standard recurring production orders can also be delivered via expedited cross-border consolidated road freight within 3–4 days transit time.