EUTECT Lösungskompetenz

Tag: pcba-protection

Does your laser soldering cause burns on the assembly?

Many factors and parameters have to be considered with regard to burns during laser soldering, ranging from the positioning, the selection of the correct focus diameter, the optimal solder wire, the process surfaces of the joints to other parameters.

Some basic settings, however, prevent burns on the assembly surface:

Is the laser’s impact angle selected correctly?

If not, it should be adjusted to prevent burns from reflections. Please note the old physical principle of angle of incidence = angle of reflection.

Is the diameter of your laser focus chosen for optimum results?

It may be necessary to focus with greater precision or to defocus. Especially for strands, PCB or flex foils several approaches are available. Feel free to contact us.

Is the solder in the form of preforms, wires or paste in the right place at the right time and available?

If this is not the case, readjustments should be made.

Is the axis, laser, solder, product or assembly positioning replicable?

Achieving this requires the integration of optical position correction.

Are the surface characteristics of the joints or the process area reproducible or possibly contaminated?

In this case you should contact your suppliers or ensure a cleane surface.

Have you selected the correct emission level in your pyrometer temperature control?

These parameters can be controlled in the machine settings.

Is your laser and pyrometer calibrated and or checked on a regular basis?

If you are not able to do this yourself, a service visit could be considered.

Do you work with the correct wire feed and pullback speeds and distances? Do you use the optimum solder wire diameter? Does your solder wire have the right flux?

These parameters are defined as part of our process evaluation. If these are no longer correct or if an evaluation has never been carried out (external systems), please contact the manufacturer’s service department. EUTECT also conducts this work on machines from other manufacturers, if this is requested by the customer.

For further, more detailed information or active support on-site, please contact us, we will help you to avoid burns on the assembly.

Do you desolder your SMD-components during selective soldering?

How to minimize the risk of desoldering SMD-components?

If this is the case, the heat input for the solder joints of the SMD-components positioned in the proximity of the THT component is usually too high. These SMD-components must be protected from excessive heat with a mask, unless a layout adjustment of the assembly is possible. Especially with high packing densities and increasing miniaturization, desoldering can be a challenge.

What to consider when using a solder mask?

However, the use of solder masks requires that some factors be taken into account already during the design of the PCB:

Ensure your THT solder joint is surrounded with at least 1.5 mm space and that high components are not positioned in the immediate vicinity. With the optimal solder mask, you can achieve a process window with maximum reproducibility. However, if you have unchangeable and narrow spaces, please do not hesitate to contact us, because we have a wealth of experience and special solutions for various problems.

Which solder mask types are available ?

There are many different types of solder masks for selective soldering. These can be manufactured in different dimensions and from different materials, additional these masks can also be used for large wave soldering. There are specific soldering masks for the selective soldering process only, that perform in combination with the right material and the appropriate soldering nozzle. In addition, masks can also be used for laser and induction soldering as well as piston soldering. In this case, they also protect the PCBA and its surroundings from reflections as well as solder and flux splashes.

For further information and your individual solder mask do not hesitate to contact us.

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