Quartz Glass Plates & Windows: Process-Grade to Optical-Grade Fused Silica

Quick Answer: A quartz glass plate (or fused silica window, when used optically) is a flat, high-purity SiO₂ component used as a process viewport, structural base plate, or precision optical window. FGQuartz manufactures both process-grade plates (0.5–50 mm thick, up to 1200×1200 mm) and optical-grade windows in JGS1, JGS2, and JGS3 grades, with flatness down to λ/10 and surface finishes from as-cut to double-side polished (DSP).

Key Takeaways

• Two Product Families: Process-grade plates for structural/thermal use, and optical-grade windows (JGS1/JGS2/JGS3) for light transmission applications.
• Wide Dimensional Range: Thickness 0.5 mm to 50 mm+, format size up to 1200×1200 mm, larger monolithic formats on review.
• Precision Optical Tolerances: Flatness down to λ/10, parallelism under 30 arc seconds, surface quality to Scratch/Dig 20/10 for optical grade.
• Broad Optical Coverage: JGS1 (far-UV), JGS2 (UV/Vis), and JGS3 (infrared) grades cover applications from deep-UV lithography to IR sensing.
• Full CNC Capability: Diamond core drilling, milling, chamfering, and double-sided lapping/polishing, all in-house.
• No Minimum Order Quantity: Single optical prototypes through volume production batches.

FGQuartz is a premier quartz plates manufacturer specializing in ultra-high-purity fused silica substrates and custom optical window fabrication, supplying customers in 40+ countries since 2005. We produce both standard precision-ground blanks and fully customized quartz plate structures engineered to exact CAD drawings — from a simple high-temperature viewport to a complex substrate with blind holes, precision slots, and stepped edges. Browse our full product portfolio.

A quartz glass plate is a flat piece of high-purity fused silica (SiO₂ ≥ 99.99%), cut and finished to a specific thickness, format size, and surface quality. The terms “plate” and “window” are often used interchangeably, but in practice they describe two different performance requirements: a plate typically prioritizes thermal stability, structural flatness, and chemical resistance for use as a base, shield, or process surface, while a window prioritizes optical transmission — low absorption, minimal wavefront distortion, and precise flatness/parallelism — for applications where light must pass through with minimal loss or distortion.

Both product types share the same underlying material advantages that make fused silica the material of choice for flat components: near-zero thermal expansion (so a plate doesn’t warp or crack under uneven heating), broad optical transmission from deep-UV through infrared, and chemical inertness that keeps the surface stable under aggressive process chemistries. FGQuartz manufactures process-grade and optical-grade quartz plates designed to withstand extreme thermal shock, aggressive chemicals, and intense UV/IR radiation, tailoring the surface finish and grade to your specific optical or mechanical requirement.

Below are the primary quartz plate components FGQuartz routinely fabricates. Whether you require a raw substrate or a complex machined interface, we deliver uncompromising precision. The table below is a quick reference; full detail on each type follows.

The following tables reflect the baseline specifications for our high-purity quartz plates. Dimensions, surface roughness (Ra), and flatness are fully customizable based on your engineering drawings. For complete material data, refer to our Technical Specifications.

1. Dimensional & Machining Range

2. Material Purity (Fused Silica)

3. Thermal & Physical Performance

4. Optical Grade Comparison

Note: Specifications represent typical values. Custom dimensions and precision tolerances are verified against customer drawings during the engineering review. Full grade detail: JGS1/JGS2/JGS3 Grade Guide.

FGQuartz bridges the gap between raw quartz ingots and finished, process-ready components. As a comprehensive quartz fabrication factory, our facility is equipped with specialized multi-axis CNC diamond machining centers designed exclusively for processing hard, brittle fused silica.

Precision Cutting & Slicing — High-tolerance waterjet and diamond wire slicing cuts quartz blocks into exact custom plate dimensions with chip-free edges, minimizing the micro-fractures that ordinary cutting methods would introduce into a brittle material.

Double-Sided Lapping & Polishing — Advanced lapping equipment ensures strict thickness tolerances, extreme parallelism, and optical-grade surface roughness (Ra) down to laser-grade requirements — this is the step that turns a raw-cut blank into a true optical window.

Diamond Core Drilling — Exact placement of through holes, counterbores, and blind holes, crucial for manufacturing vacuum flanges, gas showerheads, and optical mounting plates without cracking the surrounding material.

Multi-Axis CNC Milling — Precision milling of intricate pockets, tracking grooves, and positioning slots, used extensively in designing custom semiconductor fixtures and handling systems.

Edge Profiling & Chamfering — Machining of safety chamfers, radius edges, and complex bevels eliminates the micro-cracking risk of sharp glass edges and improves handling safety in cleanrooms.

Fire Polishing Integration — Combining cold CNC machining with subsequent oxy-hydrogen fire polishing permanently seals micro-fissures from machining and restores total surface clarity where optical transparency matters.

Whether you require a standard JGS1 optical window or a heavily engineered, multi-port vacuum chamber baseplate, FGQuartz guarantees perfect execution.

Fused silica is the workhorse optical window material, but sapphire, BK7 optical glass, and calcium fluoride are used in specific wavelength or durability niches.

Fused silica remains the default choice for most industrial and semiconductor optical windows because it combines wide UV-to-IR transmission with excellent thermal shock resistance and mechanical durability at a moderate cost. Sapphire is specified when scratch resistance or pressure tolerance is the priority; BK7 suits cost-sensitive visible-range optics; calcium fluoride is reserved for deep-UV or mid-IR wavelengths beyond fused silica’s practical range.

Use this three-step framework to specify the right plate before requesting a quote:

1. Decide plate vs. window. If the component’s job is primarily structural, thermal, or chemical containment, specify a process-grade plate. If light must pass through it with minimal loss or distortion, specify an optical-grade window and identify your working wavelength.
2. Select the optical grade (for windows). Deep-UV work (lithography, excimer lasers) calls for JGS1; general UV-Vis transmission (sterilization, sight glasses) suits JGS2; infrared sensing and thermal imaging call for low-OH JGS3.
3. Specify thickness, format, and tolerance. Define thickness, overall format size, required flatness/parallelism, and any drilled or milled features. Tighter optical tolerances (flatness, Scratch/Dig) add processing time, so specify only what your application genuinely requires.

Not sure which grade or finish fits your application? Send your requirements to our engineering team for a free feasibility review.

Quartz plate and window pricing depends on four main factors:

1. Optical grade and surface finish — an as-cut process plate costs far less than a JGS1 double-sided polished (DSP) optical window with Scratch/Dig 20/10 surface quality.
2. Thickness and format size — larger formats and thicker sections require more raw material and longer lapping/polishing cycles.
3. Tolerance requirements — tighter flatness (down to λ/10) and parallelism specifications add significant processing and metrology time.
4. Machined features — drilled holes, milled grooves, or chamfered edges add CNC processing steps beyond a plain cut blank.

For an accurate quote, send your thickness, format size, grade, and any drawings to our engineering team — quotations are typically returned within 24 business hours.

Every FGQuartz plate is inspected under our ISO 9001 quality system: thickness and flatness are verified with precision lapping metrology, and optical-grade windows undergo surface quality (Scratch/Dig) inspection before shipment.

In-service handling tip: Large-format or thin plates should always be supported across their full surface during handling and storage — edge-only or point support can introduce enough flex to permanently distort flatness on thin optical windows. For optical surfaces, clean only with lens-safe solvents and lint-free wipes to avoid scratching the polished surface.

• 20+ Years Legacy: Extensive domain expertise in fused silica machining and optical polishing.
• End-to-End CNC Capability: In-house precision cutting, drilling, multi-axis milling, and double-sided lapping.
• Uncompromising Purity: Semiconductor-grade and Optical-grade (JGS1/JGS2/JGS3) materials always in stock.
• Agile Manufacturing: No MOQ restrictions—we support single rapid prototypes to high-volume OEM blanket orders.
• Build-to-Print Precision: We manufacture strictly according to your proprietary 2D/3D CAD specifications.
• Global Reliability: ISO 9001 certified quality control securing supply chains for technology leaders in 40+ countries.

Our promise is simple: whatever geometry or optical tolerance your plate requires, FGQuartz executes it flawlessly. More about the company: About FGQuartz.

Whether you require standard thermally resilient plates, optical-grade DSP windows, CNC-drilled flanges, or highly complex milled substrates, FGQuartz is equipped to meet your exacting standards.

Submit your CAD drawings or dimensional specifications today. Our engineering team will conduct a thorough DFM review and provide a transparent quotation, typically within 24 business hours.