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159 Ort Lane, Merlin, OR 97532

Phone: +1 541 471 6256

Fax: +1 541 471 6251

www.linxtechnologies.com

AN-00504 Reflow Soldering

Revised 7/16/2018

Reflow Soldering

Reflow soldering is the most common method of attaching surface mount electronic components to a

circuit board. The goal of the reflow process is to melt the solder and heat the conductive surfaces, without

overheating or damaging any electrical components. In the conventional reflow soldering process, there are

four distinct stages, or zones, having specific thermal profiles: preheat, thermal soak, reflow, and cooling. For

high-volume assembly, surface mount components are generally auto-placed by machine.

Reflow Temperature Profile

The single most critical stage in the automated assembly process is the reflow stage. The reflow profile for

any given component should be closely followed because excessive temperatures or transport times during

reflow can irreparably damage the component. Assembly personnel need to pay careful attention to the

oven’s profile to ensure that it meets the requirements necessary to successfully reflow all components while

still remaining within the limits mandated by components requiring shorter flow periods.

Solder Reflow Practices - Connectors

Application Note AN-00504

125°C

185°C

217°C

255°C

235°C

60

120

30

150

180

210

240

270

300

330

360

0

90

50

100

150

200

250

300

Recommended RoHS Profile

Max RoHS Profile

Recommended Non-RoHS Profile

180°C

Time (Seconds)