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Top of Products  >  Solder-Aid  >  HIKARU'S DIARY ON LEARNING TO SOLDER  >  Examples of common soldering failures

Examples of common soldering failures

Resin joint

Because a flux film is present between the metals to be joined (for example, between a wire and a terminal), the metals are not electrically connected with each other. Even if they are temporarily connected, they will come off when they are used.
This failure frequently occurs in the case of uneven heat conduction. To prevent this, adjust the position of the soldering iron placement.

Cold joint

This is the most common failure. In general, conditions of soldering finish with a rough surface and no brightness are called "Cold-Joint". This failure degrades the joint strength, causing the jointed parts to come off when they are exposed to impact or vibration.
This failure frequently occurs when the heating temperature is low and the soldering tip is removed before the solder completely melts. Also, a similar condition is observed in the case where the joint part is moved before the solder solidifies (cold joint) or where too much heat is applied to the joint part (overheating).

Insufficient solder

This failure indicates the condition that solder does not thoroughly spread over the wire/lead and the wire/lead is partially exposed. This failure frequently occurs in the case where the wire/lead or terminal surface is dirty or oxidized, or exposed to uneven heat application, or where the amount of heat is not enough to solder.
To prevent this, clean the surface of wire/lead or terminal and adjust the iron position so that the soldering tip is placed on an appropriate part.

Excess Solder

This failure indicates the condition that solder spreads over the terminal excessively. This failure frequently occurs in the case where the heating time is too long or when applying solder too much.
Solder drop will not cause a particularly serious problem. However, if it causes a short-circuit between terminals, it will result in a critical failure.

For soldering, we must clean the parts to be jointed, put the soldering iron at an appropriate position, apply heat for an appropriate time, and feed appropriate amount of solder.
When large and small metal pieces are compared, it is natural that the small metal piece is heated earlier than the large one. Furthermore, solder will flow to a part at a higher temperature because of its characteristic. To do soldering well, we must make use of this characteristic.
Thermal conductivity is considerably improved by feeding a small amount of solder to the soldering tip.
Soldering usually cannot be done well the first time. Try to solder many times and you can improve your skill by trial and error.