4-3. Correction of Soldered Portion
When sudden heat is applied to the capacitor, distortion caused by the large temperature difference occurs internally, and can be the cause of cracks.
Capacitors also tend to be affected by mechanical and thermal stress depending on the board preheating temperature or the soldering fillet shape, and can be the cause of cracks.
Please refer to "1. PCB Design" or "3. Optimum solder amount" for the solder amount and the fillet shapes.
1. Correction with a Soldering Iron
ꢀ1-1. In order to reduce damage to the capacitor, be sure to preheat the capacitor and the mounting board. Preheat to the temperature range shown in Table 3. A hot plate, hot air type preheater, etc. can be used for preheating.
ꢀ1-2. After soldering, do not allow the component/PCB to cool down rapidly.
ꢀ1-3. Perform the corrections with a soldering iron as quickly as possible. If the soldering iron is applied too long, there is a possibility of which will cause deterioration of the adhesive strength and other problems.
Table 3
Chip Dimension
(L/W) Code
Temperature of
Soldering Iron Tip
Preheating
Temperature
Temperature
Differential(ΔT)
Series
GRM
GRM
Atmosphere
03/15/18/JN/21/31
32/43/55
Air
Air
350℃ max.
280℃ max.
150℃ min.
150℃ min.
ΔT≦190℃
ΔT≦130℃
*GRM031/GRM03Y/GRM151/GRM15Y are not apply correction of soldered portion.
*Lead Free Solder : Sn-3.0Ag-0.5Cu
* Please manage Δ T in the temperature of soldering iron and the preheating temperature.
2. Correction with Spot Heater
ꢀꢀCompared to local heating with a soldering iron, hot air heating by a spot heater heats the overall component and board, therefore, it tends to lessen the thermal shock.
ꢀꢀIn the case of a high density mounted board, a spot heater can also prevent concerns of the soldering iron making direct contact with the component.
ꢀ2-1. If the distance from the hot air outlet of the spot heater to the component is too close, cracks may occur due to thermal shock. To prevent this problem, follow the conditions shown in Table 4.
ꢀ2-2. In order to create an appropriate solder fillet shape, it is recommended that hot air be applied at the angle shown in Figure 1.
Table 4
Distance
Hot Air Application angle
5mm or more
45° *Figure 1
Hot Air Temperature Nozzle Outlet 400°C max.
Less than 10s(Chip(L×W): 3.2×1.6mm or smaller)
Less than 30s(Chip(L×W): 3.2×2.5mm or larger)
Application Time
3. Optimum solder amount when re-working with a soldering iron
ꢀ3-1. If the solder amount is excessive, the risk of cracking is higher during board bending or any other stressful condition.
Too little solder amount results in a lack of adhesive strength on the termination, which may result in chips breaking loose from the PCB.
Please confirm that solder has been applied smoothly is and rising to the end surface of the chip.
ꢀ3-2. A soldering iron with a tip of ø3mm or smaller should be used.
It is also necessary to keep the soldering iron from touching the components during the re-work.
ꢀ3-3. Solder wire with ø0.5mm or smaller is required for soldering.
GRM31M5C1H513JA01-01A
17
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