Glass Processing Flowchart: How Float Glass Become Different Types of Processed Glass

Modern buildings require glass with more than transparency. Through glass processing, float glass can be transformed into tempered glass, laminated glass, insulated glass units, and other architectural glazing products with improved safety, performance, and design flexibility.

With over 40 years of family experience in glass manufacturing and construction, I have worked closely with architects, contractors, and builders to understand the practical requirements of architectural glass fabrication. At REACH BUILDING, I focus on technical support, customized glass solutions, and industry insights for global partners.

In this article, I will use REACH BUILDING’s automated glass processing facilities as a practical example to explain how float glass is transformed into different types of processed glass through cutting, edge processing, heat treatment, coating, and other fabrication processes.

Step-by-Step Glass Processing Workflow

Glass processing starts with raw float glass and transforms it into finished architectural glass products through a series of controlled fabrication steps. Depending on the required performance and application, different processes such as cutting, edge finishing, heat treatment, coating, lamination, and insulating glass assembly are applied.

The following workflow shows the typical journey from float glass sheets to various processed glass products.

From One Glass Sheet to Multiple Final Products

1. Raw Glass Sheets / Float Glass

Glass processing begins with the selection of the original glass sheet. Depending on the project requirements, the base material may include clear float glass, ultra-clear glass, tinted glass, coated glass, or Low-E glass.

From my experience working with architectural glass projects, the original glass selection plays an important role in the final performance of the product. Factors such as thickness, color, light transmission, and coating type directly influence the appearance, energy performance, and application suitability of the finished glass.

Clear Float Glass	Ultra-Clear Glass	Tinted Glass	Coated Glass

2. Automatic Glass Storage & Loading

In modern glass fabrication, automated storage and loading is an important step between raw glass preparation and precision cutting. After the raw glass sheets are selected, an automated system identifies the required glass type and size, then transfers the sheets safely to the processing line with minimal manual handling.

REACH BUILDING Glass Loading System

This automated workflow reduces scratches, edge damage, and handling risks while improving production efficiency and consistency, especially for large architectural glass panels.

REACH BUILDING Gantry-Type Glass Sheet Storage System

3. Glass Sorting & Positioning

Before cutting, glass sheets are automatically sorted and positioned according to the production requirements. The system identifies the correct glass type, size, and processing sequence, then aligns each sheet accurately before it enters the cutting equipment.

Proper positioning is essential for maintaining cutting accuracy and edge quality. Any deviation during this stage may affect the final dimensions and increase material waste.

4. Laser Marking (Optional) + CNC Cutting

Before further processing, glass sheets are precisely cut according to the required project dimensions. CNC cutting equipment ensures accurate sizing and consistent edges, while laser marking can be applied when traceability, production codes, compliance information, or branding identification is required.

From my experience, accurate measurement before cutting is critical. Once glass is tempered, laminated, or assembled into an insulating glass unit, it cannot be resized through conventional cutting. Therefore, all dimensions, openings, and processing requirements must be confirmed before this stage.

REACH BUILDING Laser Marking Process	REACH BUILDING CNC Glass Cutting Machine	Glass Cutting Process with Precision Tools

5. Washing After Cutting

After cutting, glass sheets are thoroughly washed to remove glass dust, particles, and processing residues from the surface and edges. This cleaning step helps prevent scratches, surface contamination, and quality issues during subsequent processes such as edge processing, tempering, or coating.

6. Edge Grinding & Polishing

After cutting, the glass edges are processed through grinding and polishing to remove sharp edges and improve surface quality. This step improves handling safety, enhances the final appearance, and helps reduce stress concentration during later processes such as tempering.

For tempered glass production, edge quality is especially important because small chips or defects along the edge can increase the risk of breakage during heat treatment.

Learn more about how glass edge polishing improves processing quality and product reliability.

7. Washing & Drying Before Further Processing

Before heat treatment, lamination, or coating, glass sheets go through a final washing and drying process to remove dust, particles, and surface contamination.

A clean and dry glass surface is essential for achieving consistent quality in later processes. Residues or particles left on the surface may affect tempering performance, coating adhesion, or the appearance of laminated and insulated glass products.

8. CNC Processing: Drilling, Notching, and Custom Shapes

At this stage, CNC equipment is used for drilling holes, creating notches, or cutting custom shapes for doors, railings, shower enclosures, and other architectural applications.

A key point I always emphasize: all drilling, notching, and shaping must be finished before tempering, otherwise the glass cannot be modified later. This step ensures your hardware fits perfectly and the tempered glass remains safe and stable.

REACH BUILDING CNC Drilling for Architectural Glass

9. Second Washing

A final wash removes residues from drilling or CNC work. This minimizes stains, bubbles, or inclusions in the finished product.

Table 1: What Must Be Done Before Tempering?

Before glass enters the tempering furnace, all required fabrication processes must be completed. The following table summarizes which operations need to be finished before tempering and which processes can be performed afterward.

Types of Processed Glass and How They Are Made

After cutting, edge processing, and other fabrication steps, float glass can be further transformed into different types of processed glass. Each processing method changes the glass properties, such as strength, safety, thermal performance, or design flexibility, making each type suitable for different architectural applications.

From my experience working with architects, contractors, and project teams, understanding how each type of processed glass is made helps avoid specification mistakes and ensures the right glass solution is selected for each project.

Tempered Glass: Manufacturing Process and Applications

After cutting, edge finishing, washing, and any CNC preparation, the glass enters a tempering furnace. Rapid heating and cooling create compressive stress on the surface and tensile stress inside.

This is what gives tempered glass its high strength and makes it resistant to thermal shock. If it does break, the fragments are small and safer.

Because of these characteristics, I usually recommend tempered glass for doors, railings, shower enclosures, and curtain walls—areas where both strength and safety matter most.

In this article, I focus on the role of tempering within the overall glass processing workflow. For a step-by-step explanation of the complete tempering process, you can also read my detailed guide: How Is Tempered Glass Made?

⚠️ A common oversight: once tempered, glass cannot be modified. Make sure all dimensions, holes, and notches are finalized beforehand.

Heat Soaked Tempered Glass: Additional Safety Testing

Heat soaked tempered glass is a further tested version of tempered glass. After the tempering process, the glass is placed in a controlled heat soak chamber for an extended period to identify panels containing potential nickel sulfide (NiS) inclusions.

This additional testing process helps reduce the risk of spontaneous breakage after installation. While the glass maintains the strength and safety characteristics of tempered glass, heat soak testing provides extra reliability for projects where replacement would be difficult or costly.

For high-rise facades, skylights, curtain walls, and public buildings, heat soaked tempered glass is often considered when long-term safety and reduced maintenance risk are important.

To learn more about the causes of tempered glass spontaneous breakage and how heat soak testing helps improve reliability, see our detailed guides on tempered glass spontaneous breakage and how REACH BUILDING applies HST to reduce breakage risks.

Laminated Glass: Structure, Manufacturing Process and Applications

For laminated glass, the key is the interlayer. During production, PVB, SGP, EVA, or another interlayer is placed between two or more glass sheets and bonded under heat and pressure.

Once bonded, the glass no longer behaves like separate sheets. If breakage occurs, the interlayer helps hold the fragments together instead of letting them fall freely.

That is why laminated glass is often used in skylights, glass floors, railings, partitions, and other areas where the glass must stay in place even after breakage. It can also support acoustic or decorative requirements when the project needs more than basic safety.

⚠️A tip I often give clients: laminated does not always mean tempered laminated; the layers can be a mix of annealed, heat-strengthened, or tempered glass depending on the project.

Insulated Glass Unit (IGU): Structure, Manufacturing Process and Applications

Insulated Glass Unit  (IGU) consists of two or more panes separated by a sealed cavity filled with air or gas. This design improves thermal insulation, reduces energy consumption, and enhances indoor comfort.

It’s a go-to solution for energy-efficient windows, curtain walls, and residential or commercial buildings. In my experience, combining IGU with tempered or Low-E glass often provides the best balance of strength, efficiency, and comfort.

Coated Glass: Types, Coating Process and Applications

In architectural applications, coated glass is generally divided into two main categories: reflective glass and Low-E glass. Both use functional surface coatings to control solar heat, visible light, and exterior appearance.

REACH BUILDING Reflective Coated Glass	REACH BUILDING Low-E Coated Glass

Processing requirements vary by coating type, with some products coated before tempering and others after. Low-E glass performs particularly well in insulated glass units, improving energy efficiency while preserving natural daylight. I often point out to clients that Low-E coatings are particularly effective when combined with IGU or tempered glass, giving energy efficiency without compromising natural light.

⚠️ Pro tip: the processing order isn’t fixed—focus on your project requirements and whether the glass will be tempered.

Combined Processed Glass Solutions

In real projects, one process rarely suffices. Tempered, laminated, coated, and insulated processes are often combined to meet safety, thermal, acoustic, and design goals.

Examples I frequently encounter include:

• Tempered Laminated Glass

• Heat Soaked Tempered Laminated Glass

• Low-E Insulated Glass

• Laminated Insulated Glass

• Curved or Decorative Laminated Glass

This is where experience makes a difference. A processor who can integrate tempering, laminating, insulating, coating, CNC customization, and decorative finishes ensures the final glass performs as expected.

REACH BUILDING, for example, can tailor solutions based on your drawings, installation method, and performance needs, making coordination across multiple processes much easier.

Table 2: From One Glass Sheet to Multiple Final Products

One of the biggest misconceptions I see is that different glass products come from completely different materials. In reality, the same glass sheet can become very different products depending on the processing route.

Conclusion

Choosing processed glass for a project involves more than selecting the final product. The processing route, drawing review, hole positions, edge quality, tempering sequence, and final assembly all influence whether the glass can be installed accurately and perform as expected.

A reliable glass processor should understand the complete fabrication workflow, from initial design review and material selection to precision processing and final inspection.

REACH BUILDING supports architectural glass projects with over 20 years of manufacturing experience and advanced automated deep-processing production lines. From drawings to finished products, REACH BUILDING provides integrated glass fabrication solutions to help improve efficiency, reduce rework, and meet different project requirements.

FAQ

What is processed glass?

Processed glass is glass that has been fabricated after the float glass manufacturing process. Common processing methods include cutting, edge grinding, drilling, tempering, laminating, insulating, and coating to achieve specific safety, performance, or design requirements.

How is processed glass made?

Processed glass is produced by taking raw glass sheets through a series of fabrication steps, such as cutting, edge finishing, CNC processing, washing, heat treatment, lamination, or coating. The exact process depends on the final glass type and project requirements.

Can tempered glass be cut or drilled after tempering?

No. Once glass has been tempered, it cannot be cut, drilled, notched, or edge-modified. All dimensional processing, including holes and special shapes, must be completed before the tempering process.

Is laminated glass always tempered?

No. Laminated glass can be made with annealed, heat-strengthened, or tempered glass depending on your project requirements.

Is Low-E glass the same as insulated glass?

No. Low-E glass is glass with a low-emissivity coating designed to improve thermal performance, while insulated glass units (IGUs) are made by combining two or more glass panes with a sealed air or gas-filled cavity. Low-E glass is often used as part of an IGU system.

What is heat soaked tempered glass?

Heat soaked tempered glass is tempered glass that undergoes an additional heat soak test to reduce the risk of spontaneous breakage caused by nickel sulfide inclusions. It is commonly considered for applications where glass replacement would be difficult or costly.