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Laser heat treatment with VCSELs

VCSEL laser heat treatment optimizes drying, welding, sealing, soldering and heating of various surfaces and materials.

VCSEL laser heat treatment for drying, welding, sealing and heating

Many industrial processes use VCSEL laser heat treatment for various surface heating applications. As a high intensity infrared heat source, precisely directed diode laser heat treatment with selective wavelength radiation is both scalable and energy efficient. VCSEL laser arrays are versatile in both small and large area heat treatment applications, such as joining, welding, soldering, drying, heating and additive manufacturing for plastics, alloy and steel components in production processes. This narrowband radiation works well for plastic welding or laser surface melting and other processes where precise area and temperature control is crucial. In addition, VCSEL lasers support temperature measurement during heat treatment using IR-cams or pyrometers. Laser heat treating modules are well suited for highly precise and flexible large-area heating applications. VCSEL heat treatment is more flexible, more precise and more cost-effective than conventional industrial heating methods.

How does VCSEL laser heat treatment work?

Thousands of micro lasers (VCSELs) are mounted on a chip, 56 chips are mounted on each emitter, and several emitters are stacked together on a module. The resulting rectangular irradiating area can contain millions of micro lasers and output several kWs of IR power! VCSEL modules can deliver near-infrared radiation with 100 W/cm² of irradiance in a directed, large-area rectangular beam cross-section. Precise, local heat treatment of target areas without expensive laser optics or scanner systems is achieved.

Why use laser heat treatment in industrial production processes?

Advantages of using diode lasers (VCSELs) for industrial heat treatment

VCSEL laser technology offers several advantages over conventional technologies like heating with reflow ovens and hot bars, hot stamping, or lasers equipped with zoom optics.

Precise control of heat treatment areas

Selectable wavelength and local emission zones enable a precise intensity and area configuration, and high quality heating results.

Laser heating modules with scalable power

Adapt the module size to your needs, by changing the number of mounted emitters or adapting the housing.

High-speed heat treatment process

Laser power density of 100 W/cm² is much higher compared to infrared or halogen lamp output.

Tailored laser heat treatment solutions

Customize heat density and laser irradiance by selecting number of VCSEL emitters and adding lens features.

Worldwide laser heating application support

TRUMPF provides application support to customers worldwide.

What is VCSEL laser heat treatment used for?

A wide range of production and industrial processes benefit from VCSEL laser heat treatment. This includes applications like joining, welding, soldering, and softening of plastic, alloy and steel components in manufacturing and assembly lines.


VCSEL laser systems join or strongly connect materials, weld plastics and treat multi-material layers for tape laying.


Use laser heat treatment to create an impervious connection when joining different surfaces.


Laser heat treating of wet coating materials results in fast and efficient drying processes.


Surface heat treatment can be used to soften materials and increase throughput.


VCSEL systems heat the areas to be soldered locally and limit the soldering time. This leads to higher quality and throughput.

Additive Manufacturing – 3D printing

In metal 3D printing VCSEL heat treatment reduces thermal stress within the build part. A VCSEL heating system can also sinter polymer objects to build up parts by melting material.


VCSEL heating systems can be used for many applications, such as welding plastic parts together, joining the edges of furniture panels or applying heat to lay tape for composite manufacturing.

Laser transmission welding

Plastics can be welded together using laser transmission. This process joins two types of thermoplastics together using a laser beam, which passes through a transparent surface layer to heat the radiation absorbing part beneath it. The absorbing plastic base material melts and fuses the transparent joining area. VCSEL heating systems can weld and heat the application area of the workpiece simultaneously, in a single pass.

Fiber placement and tape laying processes

VCSEL laser systems offer tailored high-power laser output solutions for fiber placement and tape laying processes. Laser heat treatment offers a scalable and flexible solution for composite material production.

Laser Edge Welding (plastic welding)

VCSEL heating systems are effective for applications such as industrial production of furniture panels. Laser heat treatment ensures seamless edging and surface melting for high quality product results. A compact and reliable VCSEL laser heat treatment source can deliver directed and precisely controlled infrared laser power in high throughput production applications.


VCSEL lasers deliver accurate, high speed sealing for efficient and improved heating in applications such as battery production.

Pouch cell sealing

VCSEL heating systems can achieve up to 3x increases in sealing speed for pouch cells by applying heat for welding inside the pouch foil, close to the weld area. Laser heat treating also delivers highly accurate sealing that can extend battery cell lifetime by avoiding foil wrinkling. This process increases pouch cell quality and homogeneity.


VCSEL are versatile for variable scale applications such as battery foil drying.

Battery foil drying

After coating, battery foils are dried to remove any solvents from their active materials. Industrial VCSEL heating systems are ideally suited for large-area heat treatment processes such as foil drying. More specifically, heat treating with VCSEL laser arrays is very flexible both in terms of scalability and power density. Large surface areas can be heated with precise local control of wavelength-selective infrared radiation.


VCSEL heating systems can be used to precisely treat heating areas for specific materials such as steel and silicon wafers.


Local softening of body steel parts in the automotive industry is an efficient way to target specific areas for heat treatment such as in b-pillar applications. VCSEL solutions offer a quick and easy path for selective softening of high-strength steel parts.

Wafer heating

VCSEL laser heating modules provide homogeneous heating solutions for silicon wafer heating. Laser heat treating systems are particularly useful for Rapid Thermal Processing (RPT) in wafer production because of their highly uniform and fast heating capabilities. Using VCSEL systems, individual heating zones can be very accurately controlled. Rapid temperature increases of several hundred degrees Celsius per second can be achieved using laser heat. Thanks to outstanding local control using temperature profiles, VCSEL heat treating can help increase wafer quality.

Laser-Powered Co-Firing Process

VCSEL heating systems enable more efficient production of solar cells. Burning in the silver particle contacts on the surface of solar cells is known as "firing". Using VCSEL heating systems for this process offers a range of benefits. Fast firing with laser beams only heats the solar cells, while the rest of the furnace area remains mostly cool. Using laser beams as a heat source results in increased energy efficiency and cost-effectiveness, a smaller furnace footprint and a much longer service life. These native features of diode laser heating systems help lower production costs to a minimum.

Ultrafast cell regeneration

VCSEL heating systems can increase the efficiency of solar cells. In ultrafast regeneration, within seconds, the use of high-performance VCSEL laser modules for the irradiation of monocrystalline Si solar cells prevents reactive boron oxygen formation from occurring forever. This results in a permanent increase in cell efficiency. The laser heating process is both efficient and highly localized in terms of intensity and target area. Laser-based manufacturing processes such as ultrafast regeneration can significantly increase the efficiency of high-performance solar cells.

Light Soaking

With ultrafast light soaking, energy barriers created during production, are broken down by the intensive radiation and high temperatures generated by the VCSEL laser heating systems. The laser heat treating process lowers the internal resistance of the solar cell and makes it work more efficiently. Consequently, VCSEL heating systems can increase the efficiency of solar cells.


VCSEL lasers are very effective at soldering small contact points on PCBs while supplying higher power output than conventional technologies as needed.

Laser Assisted Soldering (LAS)

In LAS, solder balls are soldered directly on PCBs using VCSEL laser infrared heat treatment, which is particularly useful with smaller ball and pitch scenarios. For LAS, VCSEL heating technology ensures highly accurate local heat treatment and the highest quality solder interfaces. As an added benefit, laser heat treatment increases the service life of PCB boards.  

Laser Assistant Bonding (LAB)

The LAB process uses a flip-chip placed on a PCB board and solder balls as connections. The VCSEL system heats the chip from the top, and laser energy transmitted through a silicon die melts the solder balls between the chip and the PCB. VCSEL systems support larger heating areas of a complete board with several dies with higher power output than other solutions.

Additive Manufacturing

VCSEL heating systems offer unique advantages for 3D printing of metal and polymer material.

Pre-heating for metal 3D printing
Component generation using laser metal fusion

When high-volume metal parts are 3D printed, thermal gradients can often impact the sintered parts. Stresses can be minimized using laser heat from the top. Laser heat significantly reduces thermal stress and warpage on the printed part.

3D printing of polymers

Using thousands of individual addressable VCSEL lasers with concentrating optics as a light source for selective laser sintering (SLS) offers huge benefits, compared to conventional SLS printers with only one or two scanning lasers. You can achieve high resolution (250 dpi) in combination with an unmatched production speed, about 10x faster than the best conventional SLS printers for polymers, using VCSEL heating systems for this laser heat treatment process.

VCSEL heating systems in action

VCSEL heating systems support customizable intensity profiles for precise control of emission zones and power process parameters.

How are TRUMPF VCSEL laser heating systems made and how are they used?

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