How to control the mechanical stress of PCBA assembly production?

Publish Time: January 05,2019

Mechanical stress refers to the internal force that interacts between various parts of an object when the object is deformed due to external factors (force, humidity change, etc.) to resist this external factor and try to restore the object from its deformed position To the position before deformation.

The mechanical stress in the PCBA assembly manufacturing process has the following aspects:

Component molding

Controlling factor: PCB support smoothness

Standardization of part library parameter settings

Reflow soldering

Controlling factors: The slope of temperature rise / fall during reflow soldering is an important control parameter. According to the recommendations of IPC / JEDEC, the slope of temperature rise / fall is 6 ℃ / Second max

3. ICT test

Controlling factors: Fixture design prevents interference with parts

PCB board bending (PCB deformation limit board bending is less than or equal to 7/1000)

Sliver

Controlling factor:

Part layout method

l V-CUT is at least 0.5mm away from the edge of the part or PAD

0603-2210 capacitors, inductors and other easily cracked parts within 5mm of V-CUT should be vertical V-CUT

Sliver Knife Management

Strain gage verification

Low risk specification: the strain is less than 599μ ∈