Do you have solder ball formations on the wire or the solder joint when laser soldering?

For a clean, reproducible laser soldering process, a perfect solder pattern is essential. Solder ball formation during the soldering process must be avoided at all costs, as they can cause short circuits on the assembly or the amount of solder applied is not reproducible. Particularly in the case of tight packaging densities, it is essential to ensure that the soldering process is as precise as possible. If solder balls occur nevertheless, they must be eliminated. Please consider the following points:

Have you chosen the correct angle between solder wire and the angle of incidence of the laser?

If not, readjust the angle.

Can unwanted reflections be caused by product or laser head positioning?

If so, the complete structure of the soldering process should be considered. If the setup cannot be adjusted, you should consider whether reflections can be prevented by covers or masks.

Are your positioning and the conveying the lengths of the wire correctly? Do you use the correct wire speeds when feeding, during the process and during wire withdrawal?

If not, adjust the speed to avoid the formation of balls. Wire withdrawal is particularly important here, as it guarantees a reproducible process. Read more about the SWF from EUTECT.

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.

Lacking hole fill during THT-soldering?

What options support hole fill during your soldering process?

With THT-soldering it can happen that the hole fill does not form properly. In this case the solder does not completely perforate the hole and the counterminiscus is not formed 100%.

First check that the diameter of the hole in relation to the pin ratio and the joint geometry are correctly selected. If this is the case, you have the following options to optimize the process:

Mini wave or selective soldering:

Increase the temperature of the solder bath and check for the desired temperature at the process point.
Increase contact time between mini-wave and product
Increase preheating temperature, activation or preheating time
Check the optimal flux quantity
Verify that the correct flux is used in accordance to solids and other activators
More about the EUTECT IW1 & 2 module

Laser solderings

Use of a preheater to apply heat to the joints, thus facilitating hole fill
Position of the laser focus in the right angle and in relation to the product geometry, solder feed and overall product geometry
Test feeding speed of the solder wire
Additional energy input after fusing of wire
Test the optimal flux content and the correct alloy in the solder wire
More about EUTECT laser soldering

If you still have problems with hole fill, please contact us, we will help you to optimize your soldering process.

Wire bend? Problems with piston or laser soldering?

Are you busy troubleshooting the wiring clutter in your piston, induction or laser soldering automation daily?

Is your soldering process inaccurate due to wire feed, not reproducible or do you solder “antennas”?

Try to align your energy source, does not matter if soldering iron, induction outer circuit or laser focus, in such a way that the energy acts on the one hand in the joint partner with the highest heatsink and on the other hand in the solder wire. This allows a faster fusing of the solder wire and thus a thermal bridge between the connected partners and therefore allows for a better solder joint formation.

Please note the adjustable feed, process and withdrawal speeds of the solder wire, these three variables offer significant optimization possibilities.

If this does not help or if you want to optimize your takt time and intermetallic phase further, try pre-tinning the joints and then feed them into the soldering process with filler wire, paste or preform.

Would you like to know what your wire feed really did in the soldering process?

If you want to get data regarding your soldering process to know exactly what happens during the soldering process, we recommend you contact us regarding our SWF wire feed module – it’s worth it – it’s the world’s only “actio-reactio” based and power controlled wire feed in the world.

> More about the EUTECT SWF Module

As there are many different solder wire applications worldwide, there are also many different challenges for which we have developed our own solutions. Contact us and we will help you to optimize your soldering process.

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Tag: laser-soldering