Evosys 2 µm Laser Welding: Enabling Clear-to-Clear Plastic Joining with EvoClear

Non-Destructive, High-Contrast Solutions for Transparent Medical Components

This requirement typically meant that one part contained laser-absorbing additives, often carbon-based pigments. While effective, it introduced design limitations when manufacturers wanted to join two transparent components without changing material colour or formulation.

Laser plastic welding has become a widely adopted joining method in industries where cleanliness, repeatability and precise energy control are essential. Traditionally, however, laser welding of plastics relied on a transmission welding principle, where the upper plastic component needed to be transparent to the laser wavelength while the lower component absorbed the energy.

Evosys has addressed this challenge through its EvoClear technology, which uses a 2 µm wavelength laser to weld clear-to-clear plastics without the need for absorbing additives. The process opens new possibilities for industries such as medical devices, pharmaceuticals, optics and electronics where transparent polymers are commonly used.

Why Clear-to-Clear Welding Has Been a Challenge

Conventional laser plastic welding systems typically operate using near-infrared diode lasers around 800–1000 nm. In this process, the upper plastic part transmits the laser radiation while the lower component contains an additive that absorbs the energy and converts it to heat.

The generated heat melts the interface between the two parts, and clamping pressure forms a welded joint as the material cools and solidifies.

While reliable and widely used, this method requires:

One part to contain laser-absorbing pigments
A clear-to-dark material pairing
Careful control of additive concentration

For many applications, this is not a problem, but it becomes a limitation in sectors where both parts must remain transparent. Medical device manufacturers, for example, often use transparent polymers such as polycarbonate, COC, COP or PMMA so that fluid flow or internal components can be visually inspected.

Adding pigments to enable laser absorption may interfere with optical clarity, regulatory requirements or functional design, making traditional welding approaches unsuitable.

How Evosys 2 µm Laser Welding Works

Evosys developed EvoClear by using a laser wavelength of approximately 2 µm, which interacts differently with polymer materials compared with traditional near-infrared lasers.

At this wavelength, many transparent plastics naturally absorb a small portion of the laser radiation. Rather than passing completely through the material, part of the energy is absorbed directly within the polymer structure.

This controlled absorption allows heat to be generated precisely at the joint interface, enabling the two transparent parts to melt together and form a weld seam without the need for absorbing additives.

The process still follows the fundamental principles of laser plastic welding:

The laser beam is directed to the joint line between the two components.
Energy is absorbed at the interface between the materials.
Localised melting occurs at the joining surfaces.
Mechanical clamping pressure forms a homogeneous weld as the polymer solidifies.

Because the absorption behaviour is inherent to the material at the 2 µm wavelength, the process allows transparent-to-transparent joining while maintaining optical clarity.

Advantages of 2 µm Laser Welding

Design Freedom for Transparent Components

Manufacturers can maintain fully transparent components without introducing colourants or absorbing pigments. This is particularly important for products where visual inspection of internal structures is required.

Clean and Precise Energy Input

Laser plastic welding remains a non-contact process, meaning the laser energy is delivered precisely to the joint interface. This allows the surrounding material to remain largely unaffected, helping to maintain dimensional accuracy and surface quality.

Reduced Contamination Risk

Because the process does not require adhesives, solvents or mechanical vibration, it is well suited to applications requiring clean joining processes, including medical and pharmaceutical components.

Consistent and Repeatable Welding

Laser welding systems are typically controlled through programmable parameters such as power, speed and beam path. This allows manufacturers to achieve high repeatability in production environments.

Compatibility with Micro-Scale Components

The precise energy control of laser welding makes it suitable for small or delicate components, including microfluidic devices or miniaturised assemblies.

Applications Across Industry

The ability to join transparent plastics opens new opportunities across several manufacturing sectors.

Medical Device Manufacturing

Many medical devices rely on transparent polymers so that clinicians or technicians can monitor fluid flow, reactions or internal components. Applications include diagnostic cartridges, fluid reservoirs and microfluidic systems where clean, hermetic welds are required without compromising optical visibility.

Pharmaceutical and Laboratory Equipment

Laboratory consumables and fluid-handling systems often use transparent plastics to allow visual monitoring. Laser welding offers a controlled joining method that avoids adhesives that may contaminate sensitive environments.

Sensors and Electronics

Transparent polymer housings are used in optical sensors and electronic assemblies where light transmission or optical detection is required. Laser welding enables robust joining while preserving optical performance.

Consumer and Optical Products

Clear plastics are also common in consumer electronics and optical devices. Joining these components without visible seams or colour changes is a key requirement in many product designs.

Evosys Laser Welding Systems

Laser plastic welding has long been valued for its precision, cleanliness and repeatability, but the need for absorbing additives traditionally limited its use with transparent materials.

Evosys’ 2 µm EvoClear technology removes this limitation by enabling clear-to-clear polymer welding without additives, opening new design possibilities for manufacturers working with transparent plastics.

For industries such as medical devices, pharmaceuticals, electronics and optics, this approach allows the benefits of laser welding to be applied while preserving the optical properties of the materials.

As product designs increasingly rely on transparent polymers and miniaturised components, technologies such as EvoClear demonstrate how laser processing continues to evolve to meet modern manufacturing challenges.

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