Ever feel like you’re doing everything right on your production line but still dealing with messy laminators and material costs that are just a little too high? You might be scrutinizing complex material specs or equipment calibration, but the real culprit could be something much simpler: a few seconds of bad timing.

It’s a common story in solar module manufacturing. A process that worked perfectly for years suddenly starts causing problems. The key isn’t in the big steps, but in the tiny, invisible dance between vacuum and pressure. Getting this dance right separates a clean, cost-effective process from one that constantly wastes valuable material.

The Two Critical Steps in Lamination

At its heart, solar module lamination is like making a high-tech sandwich. You have your layers—glass, encapsulant, solar cells, another layer of encapsulant, and a backsheet. The laminator’s job is to heat this stack and press it together, removing all the air. This creates a single, durable unit that can last for decades.

Two actions are critical to this process:

1. The Vacuum: The machine pumps all the air out from between the layers. This is crucial because any trapped air bubbles could cause delamination and catastrophic module failure down the road.
2. The Pressure: A flexible diaphragm presses down on the module stack, ensuring the molten encapsulant flows evenly around the cells and bonds everything together.

For years, the industry standard was simple: start a timer. Pull a vacuum for a fixed period—say, 280 seconds—and then apply pressure. This time-based approach was straightforward and worked reliably with older, thicker encapsulant materials.

But the game has changed.

The Problem with Modern Materials and Old Methods

Today’s solar industry is driven by innovation. New encapsulant materials, like advanced Polyolefins (POEs), are designed to cure faster and perform better. The catch? At lamination temperatures, they have a very low viscosity.

Think of it like this: traditional encapsulants behaved like cold honey—thick and slow-moving. The new materials are more like warm maple syrup—thin and runny.

Here’s where the old timer-based method fails: if you apply pressure before the vacuum has finished its job, you’re essentially squeezing that runny encapsulant out the sides of the module.

This phenomenon is known as “squeeze-out.”

It’s more than just a mess. Squeeze-out is a quiet profit killer that leads to three major problems:

• Material Waste: Our research shows that squeeze-out can waste 3-5% of your total encapsulant material on every single module. That adds up to a significant, unnecessary operational cost.
• Increased Maintenance: The squeezed-out material sticks to the laminator’s diaphragm and transport belts, requiring frequent and time-consuming cleaning cycles that halt production.
• Compromised Quality: An inconsistent edge seal can create pathways for moisture to enter the module over its lifetime, severely impacting long-term reliability and performance.

A Smarter Approach: Listening to the Process

So, if a static timer isn’t the answer, what is? The solution is to move from a time-based system to a condition-based one. Instead of telling the machine to wait for a set number of seconds, we tell it to wait for a specific event: reaching the target vacuum level.

This is the principle behind Phase-Locked Process Control.

It works like this: the pressure ramp doesn’t begin until sensors confirm the vacuum has reached its optimal level (e.g., below 5 mbar). The start of the pressure phase is locked to the completion of the vacuum phase. It’s a dynamic, responsive system that adapts to the actual conditions inside the laminator.

„Static timers are a relic of older, more forgiving material chemistries. Today’s advanced encapsulants demand dynamic process control. You can’t just set a timer and hope for the best; you have to listen to what the process is telling you. Phase-locking is how we do that.“ — Patrick Thoma, PV Process Specialist

This simple shift in logic ensures that by the time pressure is applied, all the air is gone, and the encapsulant is perfectly ready to be pressed into place—not squeezed out the sides.

The Data-Backed Difference

This isn’t just a theoretical improvement. At PVTestLab, we’ve modeled and tested this very interaction. By implementing phase-locked control on our full-scale R&D production line, we’ve gathered concrete data on its impact.

The results are clear: shifting from a time-based cycle to a phase-locked one can reduce encapsulant squeeze-out by over 80%.

This translates directly into significant material cost savings, less downtime for cleaning, and a more reliable, repeatable edge seal on every module. It’s a foundational element of any robust process optimization strategy for modern solar manufacturing.

The takeaway is simple: in the world of advanced materials, timing isn’t just one thing; it’s everything. By synchronizing your process phases, you can stop wasting material and start building better, more reliable solar modules.

Frequently Asked Questions (FAQ)

What exactly is „encapsulant squeeze-out“?

Encapsulant squeeze-out is when the molten polymer material used to encapsulate solar cells is forced out from the edges of the module during lamination. This is typically caused by applying pressure before a full vacuum has been achieved, especially with low-viscosity encapsulants.

Is this problem only for certain types of solar modules?

While squeeze-out can occur with any module technology, it is most pronounced in designs using modern, fast-curing, or low-viscosity encapsulants like certain POEs. As the industry moves toward these higher-performance materials, the problem becomes more common.

Why can’t I just use a shorter vacuum time to speed up the cycle?

Shortening the vacuum time is risky. If you don’t allow enough time for the machine to pump out all the air and volatile organic compounds (VOCs), you risk trapping bubbles within the module. These bubbles can lead to delamination and module failure in the field. The goal isn’t a shorter cycle, but a smarter, more effective one.

How do I know if my current process has a squeeze-out problem?

The most obvious sign is visible encapsulant residue on the edges of your finished modules or on your laminator’s internal components. You can also track your encapsulant consumption per module; if it’s higher than the theoretically required amount, you are likely losing material to squeeze-out.

Is phase-locked control a software update or new hardware?

It depends on your equipment. For many modern laminators, it can be implemented as a process recipe or software adjustment that changes the control logic from a timer to a sensor-based trigger. Older equipment might require hardware upgrades to integrate the necessary vacuum sensors with the pressure control system.

Your Next Step in Process Discovery

Understanding the hidden inefficiencies in your production line is the first step toward building a more robust and profitable operation. If this exploration of process timing has sparked new questions about your own manufacturing setup, you’re on the right path.

Continue your learning journey by exploring how prototyping and structured lamination trials can provide the data you need to validate your materials and perfect your process parameters under industrial conditions.