When this element is not present and the component is connected directly to the copper pour, the high thermal conductivity of copper can cause the heat to dissipate from the pad, resulting in a cold solder joint
and insufficient PTH barrel fill.
* Cold solder joints
. The cold solder joint
signature can appear as one or more bond images with irregular edges around their perimeters (Figure 6).
The problems with these aftermarket communications cords involve problems with loose and sloppy over-braiding, cold solder joints
, and the failure to use parts called out on the drawing that can be seen in the picture below.
If not, cold solder joints
will likely result, and another solder step will be needed to complete the assembly.
As reflow was clearly achieved, and there was no evidence of cold solder joints
, a recommended step was to decrease the TAL from 90 to 60 sec., which would improve wetting without a risk of incomplete solder reflow.
The process eliminates solder bridging, cold solder joints
and environmentally hazardous materials, while preventing damage to heat-sensitive semiconductors or other components.
During assembly, this arrangement will sink the heat during reflow and cause cold solder joints
, resulting in opens or intermittent connections.
Our team was recently requested to identify the root causes of a defect that the customer had tentatively identified as cold solder joints
. In this instance, a Pb-free QFP presented some joints where solder did not wet the side and toe of the component leads (Figure 1).
The process offers the elimination of solder bridging, cold solder joints
and environmentally hazardous materials.
For detecting cold solder joints
, 3D AXI again looks at the slope of the joint.
The focus was on assembly and rework defects such as solder bridging, insufficient solder, ball misalignment and cold solder joints
. The Shadow Moire technique was used to inspect the PCB flatness and FCBGA and [mu]PGA socket warpage under the temperature profile--26, 125, 183, 225, 183, 26[degrees]C--to emulate the thermal impact in the early stage of the package and reliability study.
The other drawback is it cannot test BGA pins without specific test pads on the nets leading into the device, and it cannot functionally test ICs or catch cold solder joints