Quartz Glass Manufacturing Process

Our quartz glass manufacturing process integrates hot working, cold machining, surface treatment, and advanced fabrication. As a core part of our fused quartz fabrication process, we specialize in high-purity quartz production using precise quartz glass processing methods to deliver reliable industrial quartz component manufacturing for semiconductor, optical, and laboratory applications.

Hot Working in the Quartz Glass Manufacturing Process

Hot working is a critical stage in our quartz glass manufacturing process and a key step in our fused quartz fabrication process.

Flame Turning & Shaping

Rotating quartz blanks are shaped by a hand-controlled or CNC-guided hydrogen-oxygen torch. Used for producing tubes, rods, nozzles, and custom profiles with smooth fire-formed surfaces that require no secondary polishing.

Flame Sealing & Closing

Open tube ends are collapsed and hermetically sealed using a focused oxyhydrogen flame. Critical for vacuum-sealed envelopes, lamp bodies, and closed-end reaction vessels. Bubble-free seals achieved by controlled gas purging during closure.

Glass-to-Glass Fusion

Two or more quartz pieces are joined by localized melting and re-solidification. Enables complex assemblies: T-junctions, manifolds, multi-port reactors, and custom flanged systems — all in one seamless quartz body with no adhesives.

Fire Polishing

Cut edges and machined surfaces are briefly re-melted by an oxyhydrogen flame (surface temp ~1,700 °C). Surface micro-cracks and abrasive scratches are eliminated, yielding a flawless, fire-bright finish with Ra < 0.05 μm and improved mechanical strength.

Quartz-to-Metal Sealing

Controlled graded seals bond quartz to Kovar, molybdenum, or tungsten for hermetic electrical feedthroughs. Thermal expansion mismatch is managed through carefully staged intermediate glass layers, producing vacuum-rated, long-life assemblies.

Tube Bending & Forming

Quartz tubing is locally heated to the softening point and bent to custom angles (15°–180°) or formed into U-shapes, spirals, and coils. Used in furnace atmospheres tubes, UV lamp geometries, and custom flow reactors.

Cold Working in the Quartz Glass Manufacturing Process

Cold working plays an essential role in the quartz fabrication process by enabling precise machining, drilling, and polishing of quartz components.

These techniques are used to achieve tight tolerances and complex geometries without affecting the material’s thermal properties.

Diamond Sawing & Slicing

Precision diamond-blade cutting of quartz plates, wafers, and discs. CNC-controlled feed rates prevent chipping and subsurface cracking. Ideal for slicing ingots into blanks for optical windows or substrate wafers.

CNC Grinding & Turning

Multi-axis CNC machining centers with diamond tooling achieve complex quartz geometries — flanges, steps, grooves, tapers, and bores. Diameter tolerance ±0.01 mm, length ±0.05 mm on standard runs.

Drilling & Boring

Diamond-core drilling and ultrasonic drilling for holes from 0.5 mm to 100 mm diameter. Ultrasonic method preferred for thin-walled parts (<2 mm wall) to minimize subsurface damage.

Flat Lapping

Double-sided lapping on precision cast-iron plates with SiC or diamond slurry. Achieves flatness better than λ/10 (@ 632.8 nm) and TTV (Total Thickness Variation) <5 μm for optical windows and etalon substrates.

Optical Polishing

CNC pitch polishing and MRF (Magnetorheological Finishing) on demand. Achieves surface quality 10-5 scratch-dig per MIL-PRF-13830B. Used for laser windows, beam splitters, and UV photomask blanks.

Ultrasonic Machining

High-frequency vibration (20 kHz) combined with abrasive slurry removes material without rotation forces — ideal for complex shapes, blind cavities, honeycomb patterns, and fragile thin-section parts that CNC grinding cannot reach.

Dicing & Scribing

Automated dicing saws with diamond blades produce precision quartz chips, substrates, and small components from wafer-sized blanks. Kerf width as low as 0.08 mm; compatible with 1000 mm × 1000 mm panels.

Waterjet Cutting

Abrasive waterjet cutting for thick plates (0.5–50 mm) with complex 2D profiles. No heat-affected zone. Used for custom flange shapes, irregular windows, and prototype parts where CNC setup is too costly.

Surface Treatment for High-Purity Quartz Production

Surface treatment is a key step in the fused quartz manufacturing process to enhance surface quality, remove contaminants, and improve optical and chemical performance.

It is widely used in semiconductor and high-precision optical applications.

Acid Etching (HF / HNO₃)

Controlled chemical etching in dilute HF or buffered HF removes the damaged subsurface layer left by mechanical machining, reduces surface particle contamination, and further reduces metallic impurities on the surface. Standard treatment for semiconductor-grade parts. Final rinse in 18 MΩ·cm DI water.

AR & HR Optical Coatings

Ion-beam sputtered (IBS) and e-beam evaporated anti-reflection (AR) and high-reflectance (HR) coatings optimized for UV (193–355 nm), visible, and NIR wavelengths. Reflectance <0.2% per surface (AR) or >99.9% (HR). Laser damage threshold >10 J/cm² (@1064 nm, 10 ns).

OHC (Hydroxyl) Control

OH content in quartz directly affects IR transmission and high-temperature viscosity. Low-OH (<10 ppm) grades for IR applications; high-OH (>800 ppm) synthetic grades for UV applications. FGQuartz can specify and verify OH content by FTIR spectroscopy.

Semiconductor Clean (SC-1 / SC-2)

Full RCA clean sequence (SC-1 in NH₄OH:H₂O₂:DI; SC-2 in HCl:H₂O₂:DI) removes organic and ionic contaminants. Final DI rinse and class-100 cleanroom packaging. Particle count ≤1 particle/cm² >0.3 μm on final inspection.

Flame Hydrophobization

Selective flame treatment in an oxygen-deficient atmosphere creates a siloxane-rich, slightly hydrophobic surface. Used on quartz carrier boats and diffusion tubes to reduce wafer sticking and facilitate handling in semiconductor furnaces.

Scratch-Dig Finishing (10-5)

Final pitch polishing and MRF correction achieve surface quality compliant with MIL-PRF-13830B 10-5. Required for high-power laser windows, UV photolithography lenses, and fluorescence spectroscopy cells where scatter must be minimized.

Specialty Fabrication for Industrial Quartz Component Manufacturing

Specialty quartz fabrication combines multiple quartz processing techniques to produce complex and customized components for advanced industrial applications.

Complex Assembly Fabrication

Multi-component quartz assemblies combining fire-welded joints, cold-machined precision surfaces, and coated optical elements. Engineering drawings reviewed for DFM (Design for Manufacturability) before production begins.

Spiral & Helical Coil Forming

Continuous-flame winding of quartz tubing around mandrels to produce helical heat-exchange coils, UV reactor spirals, and custom flow-path geometries. Available in tubing OD 4–50 mm, coil pitch adjustable.

Slotted & Perforated Tubes

CNC laser or diamond-wheel cutting of axial slots, radial holes, and complex aperture patterns in quartz tubing. Used for LPCVD/PECVD gas injectors, diffusion tube end-plates, and CVD baffle tubes.

Optical Fiber Preform Tubes

Ultra-high-purity substrate tubes and overclad tubes for MCVD, OVD, and VAD fiber preform deposition. Dimensional tolerances: OD ±0.1 mm, wall ±0.05 mm, bow <0.5 mm/m. OH content matched to process specification.

Laboratory Apparatus

Custom quartz vessels, condensers, distillation columns, and reaction flasks fabricated to user drawings or standard chemistry glassware dimensions. All joints fire-polished; available with PTFE stopcocks or quartz standard-taper joints.

Large-Format Components

Quartz plates and tubes up to 1,000 mm × 1,000 mm (plates) and 500 mm OD (tubes). Special handling equipment and multi-torch fire working rigs enable production of oversized components for solar furnaces, industrial UV systems, and R&D equipment.

The quartz glass manufacturing process combines hot working, cold machining, and surface treatment techniques to produce high-performance fused quartz components.

These processes are essential for industries such as semiconductor manufacturing, optics, and laboratory equipment.