4-1.Reflow Soldering
1. When sudden heat is applied to the components, the mechanical strength of the components will
decrease because a sudden temperature change causes deformation inside the components.
In order to prevent mechanical damage to the components, preheating is required for both the
components and the PCB.
[Standard Conditions for Reflow Soldering]
Temperature(℃)
Soldering
Peak Temperature
Gradual
Cooling
Preheating conditions are shown in table 1.
It is required to keep the temperature differential between the solder and the components
surface (ΔT) as small as possible.
220℃
ΔT
190℃
170℃
150℃
2. When components are immersed in solvent after mounting, be sure to maintain the temperature
Preheating
difference (ΔT) between the component and the solvent within the range shown in the table 1.
Time
60 to 120 s
30 to 60 s
Table 1
Temperature Differential
ChipꢀDimension(L/W)ꢀCode
Series
01/02/MD/03/15/
18/JN/21/31
ΔT≦190℃
GRM
[Allowable Reflow Soldering Temperature and Time]
280
270
260
32/43/55
ΔT≦130℃
GRM
250
240
230
220
Recommended Conditions
Peak Temperature
Lead Free Solder
240 to 260℃
0
30
60
90
120
Soldering Time(s)
Air or N2
Atmosphere
In the case of repeated soldering, the accumulated
soldering time must be within the range shown above.
Lead Free Solder: Sn-3.0Ag-0.5Cu
3. When a capacitor is mounted at a temperature lower than the peak reflow temperature recommended by the solder manufacturer, the following quality problems can occur.
Consider factors such as the placement of peripheral components and the reflow temperature setting to prevent the capacitor’s reflow temperature from dropping below the peak temperature specified.
Be sure to evaluate the mounting situation beforehand and verify that none of the following problems occur.
･Drop in solder wettability
･Solder voids
･Possible occurrence of whiskering
･Drop in bonding strength
･Drop in self-alignment properties
･Possible occurrence of tombstones and/or shifting on the land patterns of the circuit board
4. Optimum Solder Amount for Reflow Soldering
ꢀ4-1. Overly thick application of solder paste results in a excessive solder fillet height.
This makes the chip more susceptible to mechanical and thermal stress on the board and may cause the chips to crack.
4-2. Too little solder paste results in a lack of adhesive strength on the termination, which may result in chips breaking loose from the PCB.
4-3. Please confirm that solder has been applied smoothly to the termination.
Inverting the PCB
Make sure not to impose any abnormal mechanical shocks to the PCB.
GRM31CB31C226ME15-01A
MURATA [ muRata ]
