White Residues on the Assembly
Possible Causes and Solutions
Anyone who has ever dealt with assembly cleaning will probably have encountered the phenomenon of "white residues". But what is it all about? Why residues at all, why white? Where do they come from? And what can be done about them? Questions upon questions - the answers are here:
WHITE residues?Multiple Causes, Pragmatic Solutions
When white residues suddenly appear on assemblies for unknown reasons, the customer is often confused - and the first idea is often the same: something must be wrong with the cleaner. However, this is only the cause in extremely rare cases. In the absolute majority of cases, there are other causes - but these can be manifold.
In many cases, changes in the assemblies are responsible. Cheaper materials, less development time or simply a change of supplier can be the cause. A supposedly more favorable offer can also have disadvantages. If the new parts are not compatible with the previous cleaning process, problems arise - not infrequently in the form of white residues. If it is not possible to switch back to the old components, the only option is often process optimization.
TRIGGERSolder Resist Mask Not Completely Cured
Another reason that often causes white residues is that the solder mask is not completely cured. In this case, water from the cleaning process can accumulate in the material of the soldermask and condense there at room temperature. This can also lead to staining. A solution that is as practical as it is pragmatic: a hot hair dryer, held over the assembly for some time, quickly makes the milky, white residues disappear.
TRIGGERSolder Paste Change
A change of solder paste is also often responsible for white residues on the plantine. If the change is made without first consulting the manufacturer of the cleaning media, the cleaner may not be able to optimally remove the new solder paste with the same system settings. Again, if the cleaner is not to be changed, in most cases other parameters will have to be changed.
zestron xpertiseWith Expertise and Analysis to Solve the Problem
In principle, however, there are a whole host of reasons why white residues can occur. Other causes include the quality or temperature of the rinse water. However, these problems can also be eliminated by adjusting the parameters or preparing the rinsing medium. If a cleaner has already been used too often, it is sometimes possible to achieve the desired result again by increasing the concentration.
YOU CAN RELY ON ITZESTRON: Individual Solutions for Every Case
In general, it can be stated that in most cases where complications with white residues occur, good results can be achieved by optimizing the process. If a solution to the problem cannot be found in this way, the Application Engineering department is always available to our customers. We analyze each case individually and together go in search of the cause. A change of cleaner is usually only necessary in the rarest of cases.
AVOID WHITE residues ON THE ASSEMBLY GROUPFor Maximum Reliability: Secure a Free Consultation Now.
whitepaper-collectionIdentify and Avoid Causes of Damage
Malfunctions and field failures in high-value electronic devices are often the cause of costly recalls and legal disputes regarding liability issues and claims for damages.
How a root cause analysis can be implemented in practice is illustrated in this white paper by means of a case study.
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