Data Sheet
Table Of Contents
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]
Temperature [°C]
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 profi le
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.