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Laser soldering

  • Pattern plastic welding

    Pattern plastic welding

  • Laser-Kunststoffschweißen - Konturschweißen

    Laser plastic welding - contour welding

    Laser plastic welding - contour welding

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Laser soldering is often used as selective laser soldering. Parts which can not be soldered with reflow or wave are soldered selectively. These can be parts which are particularly sensitive to temperature or, due to their size, need a special temperature program for soldering.

The diagram shows a soldering process that can be defined completely free with a simple programming language and stored in the LASCON® program. The green curve in the diagram shows the setpoint temperature curve. The red curve represents the real temperature by closed loop control in the laser focus (actual temperature). The black curve shows the control output to the diode laser by an analog voltage. The black curve corresponds to the right 0-100% axis scale.

First, the pad is heated to 300 ° C within a temperature ramp. Then LASCON® switches on the solder wire feeder. After approx. 1.4 s, the solder wire feed is switched off. The process can be monitored online and a good-bad decision can be programed.

As an alternative to soldering with solder wire, the laser soldering with solder paste can be performed. The paste must be applied with a dispenser. An optimized temperature program largely prevents spraying.

Advantage of laser soldering with LASCON

  •     Local heat input
  •     Exact temperature control
  •     Online quality control
  •     Delivery of large amounts of heat even on small spots
  •     With scanners, different points can be heated simultaneously or subsequently
  • Smallest solder spot <100 μm
  • Soldering temperatures 140 ° C - 350 ° C
  • Temperature closed loop control with pyrometer. 10,000 control steps per second
  • Up to 256 different scripts programmable with simple software.
  • For every pad geometry an optimized script
  • Video control and analysis with high-resolution camera
  • Soldering with solder wire feeder or paste
  • Wire feeder controlled by the script via internal bus

Main advantage of laser soldering technique is flexibility under precise control.

All process parameters like energy intake, spot size and control parameters are individually matched to every soldering joint, thus achieving supreme connections even under challenging conditions.

Laser soldering is often applied as selective laser soldering, to solder parts that are heat-sensitive, small or hard to access with conventional joining techniques ( reflow or wave soldering ).

With more than 15 years of experience in laser technology we support your soldering application, feel free to contact us for a profound consulting on your process.

The use of a high-brightness diode laser and laser process controller LASCON enables you to control the soldering process by whats important – the right temperature at the right time

Selective laser soldering is used in electronics industry to solder smd and through-hole components ( tht ) to printed circuit boards ( pcb ), as well as solar cells in pholtovoltaics industry.

Mergenthaler is supporting his customers worldwide in laser soldering production processes.

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Application example 1: – Laser soldering of ceramic PCBs

The LASCON controlled system prevents overheating and generation of cracks in the pcb

Customer problem and requirements

A tier-1 automotive supplier needs a laser soldering system for a critical ceramic PCB application:

  • Prevention of cracks in the ceramic PCB by the soldering process
  • Maximum reliability and full process traceability for all soldering joints
  • Support for installation in all plants worldwide

Solution by Mergenthaler

  • LASCON controlled laser system with 60W power; integrated pyrometer for closed loop temperature control; integrated precision wire feeder controller
  • LH103 processing head with laser, pyrometer and video port
  • Accurate temperature control and optimized soldering script ensure process stability and crack prevention
  • Testing and optimization were conducted in our own laser soldering laboratory
  • Installation on site was carried out by Mergenthaler

Status quo

  • The system has been running for 20,000 hours; no downtime and no need for repairs
  • We have become a partner of choice for laser applications worldwide
Soldering of components on ceramic PCBs

Application example 2 – Soldering on sensor PCBs

The combination of LASCON and machine vision technologies generates a flexible and reliable laser soldering system

Customer problem and requirements

A tier-1 sensor manufacturer wants to produce approx. 200 different sensor types in small lots upon customer request:

  • System needs to support the production of a wide variety of PCBs
  • Connector pins have to be soldered on the PCB

Solution by Mergenthaler

  • LCL laser system with integrated LASCON controller; LH103 laser head
  • Integrated, coaxial machine vision system to correct the position of the laser head according to the PCB soldering pads
  • The sensor type is detected by the PLC, which sends the corresponding laser soldering script to the LASCON controller via the Ethernet bus
  • The scripts are executed and processed by the laser system
  • Soldering is performed according to IPC 610 A and shows excellent penetration in the through-hole solder joint
  • Testing and optimization were conducted in our own laser soldering laboratory
  • Installation and integration with existing equipment carried out on site 

Status quo

  • The system has been running for 24 months
  • No downtime and no need for repairs
Soldering of connector pins on PCBs for different sensor types