Soldering systems solve high-power LED dilemmas

A new range of soldering systems has been developed specifically for processing high-power LEDs.

A new range of soldering systems has been developed specifically for processing high-power LEDs.

One of the new developments in lighting applications are the Luxeon emitters from Lumileds.

These are the world's brightest LEDs offering up to 120 lm per single source.

Power and superb lumen maintenance, long lifetime and low energy consumption, far exceeding other standard and high-flux LEDs, are hallmarks of Luxeon.

The challenge of working with these LEDs is that they have to be soldered on an MCPCB (metal composite printed circuit board).

This MCPCB is needed to distract the heat from the LED that will be developed during operation.

And as the maximum temperature of the LED may not exceed 106C, a reflow oven will not do the job.

A selective soldering system, such as a hot-bar system must be used.

Using aluminium as a substrate creates a big heatsink during soldering.

Therefore the soldering system needs to generate a high energy density in a short timeframe.

Unitek Eapro started to develop this technology 7 years ago.

At that time the first two production machines were built for Lumileds, producing the "Flood" product, designed among other things for traffic lights.

The soldering process at that time was based on pulsed heat generated by a Uniflow power supply.

The possibilities for these high-power LEDs are enormous.

Almost all lighting applications can be replaced by this technology, with the advantage of a long product lifetime and no need for maintenance.

One of the bottlenecks for mass production of these LEDs used to be the soldering equipment pricing.

Unitek Eapro has developed three new soldering systems that are able to make the solder joints on the aluminium substrate with the lowest possible costs.

The three new systems start with a desktop series equipped with a special soldering head for laboratory and prototyping applications.

Process stability and repeatability is important, but system throughput is of minor importance.

Two connections (both legs of the LED) are soldered simultaneously.

When the volume product is ramping up, the output of the system will soon become an important issue.

Unitek Eapro offers two different solutions for this.

One of them is a tabletop x-y-z robot.

In this machine an x-y-z soldering movement can be programmed.

The soldering is performed automatically, but the substrates must be manually loaded into the machine.

The high-end system is a complete inline system with automatic fiducial alignment, x-y-z movement and solder head rotational possibility for soldering LEDs.

Placed under different angles this equipment has the highest throughput/cost ratio, and can be integrated into any pick and place production line.

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