Weidmüller Interface GmbH & Co. KG

Klingenbergstraße 16

D-32758 Detmold

Germany

Fon: +49 5231 14-0

Fax: +49 5231 14-292083

www.weidmueller.com

300

250

217

200

150

100

50

0

0

50

100

150

200

250

300

350

Time [sec]

preheating

Melting point lead-free solder paste

Heating rate: < 3 °K/s

Cooling rate: < 6 °K/s

180 °C

190 °C

235 °C

245 °C

254 °C

approx.

60 s > 217 °C

Continuous line: Typical process

Dotted line:

Process limits

Recommended reflow soldering profile

Reflow Solder Profile

We reserve the right to make technical changes.

Reflow soldering profile

The perfect soldering profile for SMT Surface Mount Technology is one the most exiting question in SMT production.

But there are more than one correct answer: The diagram of temperature-on-time is related to processing features of

solder paste and to maximum load of components.

We have to consider the following parameters:

• Time for pre heating

• Maximum temperature

• Time above melting point

• Time for cooling

• Maximum heating rate

• Maximum cooling rate

We recommend a typical solder profile with associated process limits. With preheating components and board are

prepared smoothly for the solder phase. Heating rate is typically ≤ +3K/s. In parallel the solder paste is ‚activated’. The

time above melting point of 217°C the paste gets liquid and components and boards begin to connect. The maximum

temperature of 245°C to 254°C should stay between 10 and 40 seconds. In the cooling phase at ≥ -6K/s solder is

cured. Board and components cool down while avoiding cold cracks.