What is the Wetting Balance Test?
The wetting balance test is a systematic solderability examination that tracks the wetting pressures among molten solder and the test surface over time. For PCB, this test is required. It is used to determine the readiness to accept solder on both lead-based and non-leaded top mount and through-hole parts, using either lead-free or lead-free soldering. You ought to get equipped with decent wetting balance test equipment for this.
The Solder wetting test is another thing to acknowledge when you think about the wetting balance test. A surface’s solderability gets determined by its solder wetting properties. Solder wetting refers to the creation of a reasonably homogeneous, clean, and unbroken coating of solder on the soldered area with good adhesion. Non-wetting, on the other side, occurs when the solder covering comes into contact with the surface but does not attach entirely to it, exposing the area or a portion of it.
What is the Solder Wetting Test?
The electrical contact on your printed circuit board gets made with solder (PCB). Solderability is a measurement of how well melted solder wets metal to establish links. It is one of the essential PCB testing techniques. The Solder wetting test can inform your PCB analyzer if the adjoined parts, such as leads and terminations, can endure the high temperatures associated with soldering.
It also decides if keeping these parts has an effect on the ability to solder to the PCB when they get used. Acknowledging the solderability of parts and the board will help you avoid PCB problems and enhance the quality of your finished product.
Fundamentals of the Wetting Balance Test:
- The Wetting Balance Test is used to calculate the wetting pressures among molten solder and a PCB over time. This vital test determines how long it takes for the solder to wet the component’s ending ports on a PCB.
- The PCB is placed into and retrieved from a hot solder pot at a fast pace (1 to 5 mm/sec) during the inspection. While the PCB is placed and withdrawn in a vertical way, the solder pot is stable for 6 to 10 seconds. In a vertical way, forces such as surface tension and buoyancy operate on the surface.
- There are refusing pressures in addition to wetting pressures, as seen in the illustration on the minus axis. The rejecting force exerted upwards, whereas the soaking load applied downwards.
- The velocity of sample entry is fast enough that it hits the solder pot’s bottom before the wetting pressures kick in. The rejecting pressures are relatively strong. It is why the arc increases from the minus axis. The wetting pressures eventually overwhelm the rejecting pressures, as seen by the arc on the plus axis.
- When the magnitudes of both pressures are equal, they intersect the zero-axis. It is known as Time-to-Zero. When solder adheres to a PCB sample, it forces it to travel lower, leading to a positive curve shift.
- The Wetting Balance test is a quick, automatic, and fully evaluative way of estimating whether or not a sample has succeeded or failed. We need a quantitatively established test procedure to gain clear-cut data on solderability verification.
Why is the Wetting Balance Test Necessary?
The wetting balance test, it goes without saying, is a must-do. So much so that when it comes to components, the wetting balancing test is a must. The things involved must be solderable to ensure a successful soldering operation. The wetting capability of the parts by the fluid solder is a crucial characteristic of solderability. The most common test for determining the wettability of elements, both lead-based and surface-mount, is the wetting balancing test technique.
Things to consider for the Wetness Balance Test
The test may be carried out under real-world circumstances, with the same flux and solder bath temp as in the regular process. It will provide a clear indicator of the item’s solderability during the soldering process.
However, in most circumstances, the test is performed at a reduced solder bath temp of 10 to 15°C, using a specific low enabled sample flux. If the solderability standards get fulfilled during this evaluation, the items can get utilized in manufacturing. And it is without solderability issues after a suitable amount of time has passed.
Other sorts of PCB-soldering test
A surface’s solderability gets determined by its solder wetting properties. Solder wetting refers to the creation of a reasonably homogeneous, clean, and unbroken coating of solder on the soldered area with good adhesion. Non-wetting, on the other hand, occurs when the solder covering comes into contact with the surface but does not attach entirely to it, exposing the surface or a portion of it.
For leaded items, the wetting balance test can also be performed to assess thermal solderability or specified soldering range. There are different types of PCB soldering tests if you aren’t a fan of the wetting balancing test.
- Surface mount simulation test
All surface mount technology (SMT) parts may get tested using the surface-mounted simulation process, even those that can’t be tested using conventional PCB testing procedures like dip and look. A ceramic sheet is screen-printed with a particular solder paste. The part is then inserted into the paste and reflowed using a convection pattern.
- Dip and Look
It is one of the tests that have received widespread recognition. Dip and look treats the lead and dismissals to up to eight hours of steam treatment, speeding the aging process. (This is why dermatologists recommend avoiding saunas and shower facilities!)
The parts then get dipped into solder utilizing triggered rosin flux by the inspectors. Ultimately, they get examined to make sure they’re up to code. The physical and visual characteristics of a specimen get used to determine whether it passes or fails the test when using the Dip and Test technique.
Conclusion
The wetting balancing test plots the wetting pressures applied by molten solder on the sample stage with respect to time as it gets dipped into and kept in the solder solution.
