3.2

Stencil opening design

Figure 15. Stencil opening recommendations

200µm

500µm

587µm

587µm

(Stencil opening aligned

with footprint dimensions)

Top_Layer

Stencil_Opening

3.3

Solder paste

1.

100 µm solder stencil thickness is recommended to be drunk

2.

Halide-free flux qualification ROL0 according to ANSI/J-STD-004.

3.

“No clean” solder paste is recommended.

4.

Offers a high tack force to resist component movement during PCB movement.

5.

Solder paste with fine particles: powder particle size is 20-45 μm.

3.4

Placement

1.

Manual positioning is not recommended.

2.

It is recommended to use the lead recognition capabilities of the placement system, not the outline centering

3.

Standard tolerance of ±0.05 mm is recommended.

4.

1.0 N placement force is recommended. Too much placement force can lead to squeezed out solder paste

and cause solder joints to short. Too low placement force can lead to insufficient contact between package

and solder paste that could cause open solder joints or badly centered packages.

5.

To improve the package placement accuracy, a bottom side optical control should be performed with a high

resolution tool.

6.

For assembly, a perfect supporting of the PCB (all the more on flexible PCB) is recommended during solder

paste printing, pick and place and reflow soldering by using optimized tools.

MLPF-WB55-01E3

Stencil opening design

DS12804 - Rev 3

page 9/13