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.

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.

2. When components are immersed in solvent after mounting, be sure to maintain the temperature difference (ΔT)

between the component and the solvent within the range shown in the table 1.

Table 1

Recommended Conditions

In the case of repeated soldering, the accumulated

Lead Free Solder ： Sn-3.0Ag-0.5Cu

soldering time must be within the range shown above.

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.

Make sure not to impose any abnormal mechanical shocks to the PCB.

Inverting the PCB

Item

Lead Free Solder

Peak Temperature

240 to 260℃

Atmosphere

Air or N2

GQM

03/15/18/21

ΔT≦190℃

GQM

22

ΔT≦130℃

[ Standard Conditions for Reflow Soldering ]

Series

Chip Dimension(L/W) Code

Temperature Differential

[ Allowable Reflow Soldering Temperature and Time ]

GQM1555C2DR10WB01-01A

17