Soldering Recommendations

Ka-Ro QS modules are compatible with the industrial standard reflow profile for Pb-free solder according to IPC/JEDEC J-STD-020. Ka-Ro will give following recommendations for soldering the module to ensure reliable solder joint and operation of the module after soldering. Since the profile used is process and layout dependent, the optimum profile should be studied case by case. Thus following recommendations should be taken as a starting point guide.

• Refer to technical documentations of particular solder paste for reflow profile configurations.

• Avoid using more than one flow / Only one reflow cycle is allowed.

• A 120μm stencil thickness is recommended.

• Aperture size of the stencil should be 1:1 with the pad size.

• A low residue, “no clean” solder paste should be used due to low mounted height of the component.

Recommended stencil design

QSX stencil design

QS stencil design

Solder Paste

Voiding is a topic for many electronics manufacturers. The proposed stencil design provides gas escape routes during soldering to reduce voiding.

However, the result depends on many factors. A good overview can be found on this page:

https://fctsolder.com/solder-voiding/

Low voiding solder paste is available from many suppliers. Some examples:

• https://koki-global.com/product/#solder-paste

• https://fctsolder.com/product-category/solder-paste/