14 min read
How Are Aluminum Windows Manufactured? A Deep Dive into Our Factory Process
When you specify an aluminum window for a commercial tower or a luxury villa, you’re making a decision that will affect the building’s performance for decades. But have you ever stopped to ask what actually separates a high-performance aluminum window from one that leaks, drafts, or corrodes within a few years?
The answer isn’t just in the aluminum profile itself—it’s in the manufacturing process. The precision of the cuts, the quality of the surface treatment, the integrity of the thermal break, and the rigor of the final inspection all determine whether that window will perform as engineered.
At Jusen Doors & Windows Manufacturing Co., Ltd., we’ve spent over 20 years perfecting both solid wood processing and aluminum window manufacturing. Our factory operates its own wood drying, spray finishing, and aluminum processing workshops, which means we control quality at every single step—from raw material to finished product. In this guide, we’ll walk you through exactly how we manufacture aluminum windows inside our facility, so you understand what you’re really getting when you partner with us.
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Raw Material Selection and Preparation: The Jusen Standard
The quality of a finished window is determined before the first cut is made. We select aluminum alloy billets—typically 6063-T5 or 6063-T6—for their excellent strength-to-weight ratio and corrosion resistance. These alloys are the industry standard for architectural applications because they offer the structural integrity needed for large spans while remaining lightweight enough for easy installation [1].
Our 20+ years of experience in aluminum processing has taught us that sourcing premium-grade alloys is non-negotiable. We’ve seen what happens when manufacturers cut corners on raw material: windows that fail under wind load, frames that corrode in coastal environments, and profiles that warp during temperature fluctuations. That’s why we maintain strict supplier qualification protocols and test incoming material batches for alloy composition and temper.
Cutting and Mitering for Precision
Once the raw profiles arrive at our factory, they move to our in-house aluminum processing workshop. Here, high-speed CNC cutting machines slice the profiles to exact lengths with precise 45-degree or 90-degree angles. The tolerance on these cuts matters—a fraction of a millimeter off can create gaps that compromise the window’s structural integrity and weather resistance.
Because we operate our own processing workshop, we can accommodate custom sizes without relying on third-party suppliers. Whether you need a standard 600mm x 1200mm casement window or a custom 3-meter fixed panel for a commercial facade, our CNC equipment maintains tolerance levels down to the millimeter. This capability is particularly valuable for architects working on projects with non-standard dimensions.
Pre-Treatment and Surface Cleaning
Before any coating is applied, the aluminum profiles undergo a chemical pre-treatment process. This involves degreasing and etching to remove impurities, oxidation, and any residual oils from the extrusion process. This step is critical—if the surface isn’t properly prepared, the final coating won’t adhere correctly, leading to peeling, chipping, or fading within a few years.
Our pre-treatment line is carefully controlled to ensure consistent results across every batch. We monitor solution concentrations and bath temperatures to maintain the exact chemical balance required for optimal coating adhesion. This attention to detail is why our windows maintain their appearance even in harsh climates with high UV exposure and salt-laden air.
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The Art of Aluminum Profile Processing and Machining
This is where the raw profile begins to transform into a functional window. The simple bars become complex frames with drainage systems, hardware channels, and reinforcement cavities. It’s a process that requires both sophisticated machinery and experienced engineers who understand how every component will function in the final assembly.
CNC Drilling and Punching
Our CNC machining centers create precise holes for hinges, locks, handles, and drainage slots. These machines follow digital files generated from our engineering team’s shop drawings, ensuring that every hole is positioned exactly where it needs to be—no more, no less.
This automation serves a dual purpose. First, it virtually eliminates human error. Second, it dramatically speeds up our production lead times. For our B2B partners—whether you’re a contractor managing a tight construction schedule or a dealer fulfilling multiple orders—this efficiency translates directly into faster project completion.
Corner Crimping and Assembly
The mitered corners are joined using corner cleats and specially formulated structural sealants. Our hydraulic corner crimping machines apply consistent pressure to ensure the frame is perfectly square and structurally rigid. A poorly assembled corner can cause the entire window to rack out of square, leading to operational issues and air leaks.
We also use structural sealants that bond with the aluminum to create a watertight seal. This isn’t just about keeping rain out—it’s about preventing moisture from penetrating the frame and causing corrosion over time. Our assembly process has been refined over two decades to ensure that every corner joint meets our strict quality standards.
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Reinforcement and Thermal Break Installation
Standard aluminum alone isn’t always sufficient for modern building requirements. High-rise structures, large fixed panels, and energy-efficient homes all demand additional engineering. This is where we tailor the window to the specific project requirements.
Installing Steel/AL Reinforcement
For large fixed panels or areas with high wind loads, we install steel or aluminum reinforcement inserts inside the hollow cavities of the frame. Our engineering team calculates the required gauge of reinforcement based on the window dimensions, the building’s location, and the expected wind pressures. This isn’t guesswork—it’s structural engineering based on established formulas and our experience with projects across different climate zones [2].
For example, a ground-floor window in a sheltered courtyard might not need reinforcement, while a 20th-floor window facing the ocean absolutely does. We work with you to determine the right specification for your project, ensuring safety and stability without over-engineering.
Polyamide Thermal Break (Insulation)
Energy efficiency is no longer optional in modern construction. Building codes around the world are tightening, and clients increasingly demand windows that reduce heating and cooling costs. Our aluminum windows can be fitted with polyamide thermal break strips—nylon-based separators that physically disconnect the interior and exterior aluminum frames.
During manufacturing, we insert and roll the polyamide strips into the profile, creating a continuous thermal barrier. This significantly improves the window’s insulation performance, reducing heat transfer by up to 40% compared to non-thermal-break aluminum windows [3]. For villa real estate developers and architects working on energy-certified buildings, this feature is often a requirement rather than an option.
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Surface Finishing: Spraying and Anodizing (Aesthetics & Protection)
Beyond structural performance, the surface finish determines the window’s architectural appeal and its longevity. A poor finish will fade, chalk, or peel within years, ruining the building’s aesthetic and requiring costly replacement.
Because we operate our own spray finishing workshop, we maintain strict control over the environment and application process. This ensures a flawless finish on every batch—whether you need a solid RAL color or a wood-grain finish that mimics timber.
Powder Coating Technology
Our powder coating line uses electrostatic spray technology. Here’s how it works: charged powder particles are sprayed onto the grounded aluminum profile, and the electrostatic charge causes the particles to adhere evenly to the surface. The profile then passes through a curing oven, where the powder melts and fuses into a durable, scratch-resistant skin.
This process creates a finish that’s significantly more durable than liquid paint. It resists chipping, scratching, and UV degradation, making it suitable for exterior applications in harsh environments. We offer a wide range of RAL colors, so you can match your project’s architectural specifications precisely.
Wood Grain Sublimation (Optional)
One of our most popular finishes for villa projects is wood grain sublimation. This process transfers a wood-grain pattern onto the aluminum surface using heat and pressure. A special film with the wood pattern is applied to the powder-coated profile, and the assembly is heated in a vacuum oven. The heat causes the ink to sublimate—turning from solid to gas—and penetrate the powder coating, creating a permanent wood-grain finish that won’t peel or fade.
This gives architects and developers the aesthetic warmth of timber with the durability and low maintenance of aluminum. It’s a popular choice for residential projects where clients want a premium look without the upkeep of real wood.
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Glass Fabrication and Glazing Process
A window is more than just a frame—the glass unit is vital for insulation, safety, and acoustic performance. While we don’t manufacture glass ourselves, we manage the supply chain for double and triple glazed units, ensuring that the glass is sealed and fitted to our frames with precision to prevent fogging and drafts.
Cutting and Tempering
Glass is cut to exact dimensions using automated cutting tables. For safety applications, the glass is then tempered—heated to over 600°C and rapidly cooled—to create a product that shatters into small, harmless pieces rather than dangerous shards. Tempered glass is required by building codes in many jurisdictions for doors, sidelights, and other high-risk areas [4].
Insulated Glass Unit (IGU) Assembly
For energy-efficient windows, we assemble insulated glass units. Multiple panes are separated by spacers—typically aluminum or warm-edge composite—and sealed with butyl and silicone to create an airtight cavity. This cavity is often filled with argon gas, which has lower thermal conductivity than air, further improving insulation performance.
The assembled IGU is then carefully installed into the prepared aluminum frame using specialized glazing blocks and gaskets. The blocks support the weight of the glass, while the gaskets create a weathertight seal. Proper installation is critical—if the glass is fitted too tightly, thermal expansion can cause cracking; too loosely, and the window will rattle and leak air.
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Hardware Installation, Sealing, and Final Adjustment
The moving parts determine the user experience. A window with poor hardware will be difficult to operate, insecure, and prone to drafts. This is where the window becomes a functional, secure product.
Installing Multi-Point Locks and Hinges
We install a variety of hardware accessories—from multi-point locking systems to friction stays—based on your specification and budget. Multi-point locks engage at multiple points along the frame, providing superior security and creating a tighter seal when closed. The hinges are precisely adjusted to ensure smooth operation and airtight compression.
For our OEM and ODM clients, we can source and install hardware that meets your specific requirements, whether that’s a particular brand of lockset, a specific finish on the handles, or a custom locking configuration. We support private labeling, so the final product carries your brand, not ours.
Weather Sealing and Gasket Installation
The final step in assembly is inserting EPDM rubber gaskets around the frame and sash. EPDM (ethylene propylene diene monomer) is a synthetic rubber with excellent resistance to weathering, ozone, and temperature extremes. It maintains its flexibility from -40°C to +120°C, ensuring a consistent seal throughout the window’s service life.
This step is critical for achieving high water-tightness and air-tightness ratings. We test our windows to international standards, and the gasket installation process is carefully controlled to ensure there are no gaps or compression issues that could compromise performance.
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Rigorous Quality Inspection and Packaging
Before shipping globally, every unit must pass a strict checklist. This is the final guarantee of quality—and it’s where we catch any issues before they reach your job site.
Dimensional and Functional Testing
Each window undergoes dimensional checks to verify that all measurements match the approved shop drawings. We check squareness, ensuring the frame corners are at perfect right angles. We test the operation of all moving parts—opening, closing, locking—to ensure smooth, consistent function.
For water tightness, we conduct spot checks using spray booths that simulate heavy rain. Windows that pass this test are certified as meeting our weather performance standards. This testing is particularly important for projects in regions with high rainfall or typhoon-prone areas.
Protective Film and Foam Packaging
Because we handle the final inspection and protective packaging in-house, we can guarantee that products arrive safely at international job sites. Each window is covered with protective film to prevent scratching during transit. Foam corner protectors are fitted to absorb impacts. The windows are then packed in reinforced wooden crates specifically designed for sea freight.
This packaging protocol has been refined over years of global shipping experience. We understand that a damaged window arriving at your job site means project delays, cost overruns, and frustrated clients. Our packaging is designed to prevent that, and our comprehensive after-sales support includes shipping damage protection.
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Why Partner with Jusen for Your Aluminum Window Needs?
When you work with a full-scale manufacturer rather than a trading company, you get more than just a product—you get a partner who controls every aspect of production and can respond to your needs with flexibility and speed.
We are a one-stop OEM & ODM partner. This means we can manufacture windows to your exact drawings (OEM) or work with our in-house engineering team to design custom profiles and solutions based on your project requirements (ODM). We also support private labeling, so the windows carry your brand.
Our flexible MOQs allow you to start with smaller orders to test the market or begin new projects without excessive upfront inventory costs. Our production lead times are competitive because we control our own workshops. And our engineering team can provide customized shop drawings and formal quotations within 24 hours of your inquiry.
We welcome global distributors, builders, architects, and project partners. Whether you’re working on a single luxury villa or a multi-building residential development, we have the capacity, experience, and commitment to quality to deliver.
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How Do We Compare to Alternative Window Materials?
To help you understand where aluminum windows fit in the market, here’s a comparison with the alternatives we also manufacture:
| Feature | Aluminum Windows | Solid Wood Windows | uPVC Windows |
|---|---|---|---|
| Durability | Excellent—resistant to corrosion, warping, and pests | Good—requires regular maintenance to prevent rot | Good—but can become brittle in extreme cold |
| Thermal Performance | Good with thermal break; excellent with double/triple glazing | Excellent—wood is a natural insulator | Excellent—uPVC has low thermal conductivity |
| Aesthetics | Modern, slim sightlines; available in wood-grain finishes | Classic, premium appearance; can be painted or stained | Limited color options; can look dated |
| Maintenance | Low—no painting or sealing required | High—requires periodic refinishing | Low—but difficult to repair if damaged |
| Structural Strength | Excellent—suitable for large spans and high wind loads | Good—but limited in maximum span | Moderate—requires steel reinforcement for large openings |
| Cost | Mid-range | High | Low to mid-range |
| Lifespan | 40-50+ years with minimal maintenance | 30-50 years with proper maintenance | 20-35 years |
Choose aluminum if you need slim sightlines, large glass areas, or low maintenance with excellent durability. Choose solid wood if you’re working on a heritage project or want a premium natural aesthetic and are prepared for ongoing maintenance. Choose uPVC if budget is the primary constraint and thermal performance is your main concern.
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Frequently Asked Questions About Our Manufacturing Process
What is the typical lead time for a bulk order of custom aluminum windows?
We understand that project timelines are critical. Since we operate our own aluminum processing workshops, our standard production lead time is highly competitive and faster than many trading companies. For standard profiles and finishes, we typically quote 3-5 weeks from approval of shop drawings. Custom profiles or specialized finishes may require additional time. We encourage you to Send Inquiry for an exact timeline based on your order volume and customization level.
Can Jusen match specific RAL colors or wood grain finishes for our project?
Yes. Our in-house spray finishing workshop supports both powder coating in a wide range of RAL colors and wood grain sublimation. We can match your architect’s specifications precisely to ensure the aesthetic integrity of your building design. If you have a specific color reference, send it to us with your inquiry, and our team will confirm we can match it before you place your order.
Do you support OEM or ODM for aluminum windows?
Absolutely. As a full one-stop OEM & ODM service provider, we can manufacture windows to your exact drawings (OEM) or work with our in-house engineering team to design custom profiles and solutions based on your project requirements (ODM). We also support private labeling, so the final product carries your brand. This flexibility is particularly valuable for dealers and distributors who want to offer their own product line without investing in manufacturing infrastructure.
How do you ensure the windows are not damaged during international shipping?
We have developed a robust packaging protocol specifically for global exports. Each window is covered with protective film, fitted with foam corner protectors, and packed in reinforced plywood crates designed to withstand the rigors of sea freight. This, combined with our comprehensive after-sales support, ensures your order arrives in perfect condition. We also provide shipping damage protection as part of our service commitment.
What is the minimum order quantity (MOQ) for a construction project?
We pride ourselves on flexibility. While we cater to large-scale villa real estate developers and construction projects, we also work with retail dealers on smaller initial orders. Our MOQs are flexible, typically starting from 50-100 units for standard windows, though this can vary based on the specific product and customization level. We work with our partners to find solutions that meet their needs without excessive upfront inventory costs.
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The Jusen Difference: What You Get When You Partner With Us
The manufacturing process we’ve walked through isn’t just a sequence of steps—it’s a reflection of our philosophy. We believe that quality isn’t an accident; it’s the result of controlled processes, skilled craftsmanship, and a commitment to continuous improvement.
When you partner with Jusen, you’re working with a team that has spent over two decades refining these processes. We’ve seen the evolution of aluminum window technology, from simple single-glazed frames to sophisticated thermally broken systems with triple glazing. We’ve adapted to changing building codes, evolving aesthetic preferences, and the growing demand for energy efficiency.
This experience translates into practical benefits for you: windows that perform as specified, lead times that respect your schedule, and support that continues long after the containers have left our factory.
Understanding the manufacturing process helps you choose the right partner. You now know what questions to ask and what standards to demand. We invite you to experience the Jusen difference for your next construction project.
Alternatively, you can also Contact Our Team to discuss your project specifications. We’ll respond with customized shop drawings and a formal quotation within 24 hours.
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References
- The Aluminum Association. “Aluminum Extrusion Alloys for Architectural Applications.” https://www.aluminum.org/product-markets/extrusions
- American Architectural Manufacturers Association. “AAMA/WDMA/CSA 101/I.S.2/A440-17: Standard/Specification for Windows, Doors, and Unit Skylights.” https://www.aamanet.org/
- European Aluminium Association. “Thermal Break Technology for Aluminum Windows.” https://www.european-aluminium.eu/
- International Code Council. “International Building Code (IBC) — Glazing Requirements.” https://www.iccsafe.org/
