What Issues May Take Place in PCB SMT Assembly?
SMT is a critical step in the PCB assembly process of PCBA factories, and it is also one of the necessary techniques for fast turn PCB assembly. For that reason,
PCB assemblers need to adhere to the corresponding treatments during surface mount install technology
patching to stay clear of issues throughout patching. We have spoken about SMT procedure specs and
typical anomalies before. So, what issues generally take place during PCB SMT assembly?
1. Material Throwing Issue
Material throwing is just one of one of the most usual issues in SMT production processing.
The key symptom is that the nozzle can not get parts, or the picked-up elements are not mounted on thePCB.
There are 2 primary factors for the trouble of throwing materials:
1) Poor Suction
The reasons for bad suction include nozzle blockage, uneven nozzle surface mount, incorrect feeder
position, incorrect element density set in the program, unreasonable selecting elevation setup in the
choice and location maker, and so on.
2) Poor Recognition
The factors for bad recognition include contaminant and dust on the nozzle surface, dust or scratches on
the reflective surface of the nozzle, contamination on the glass cover and lens of the part recognition
cam, etc.
2. Incorrect Parts Trouble
Wrong parts are just one of one of the most serious troubles in the SMT place technology patch handling
and production process. When incorrect parts take place, the item will certainly be scrapped and cause
heavy economic losses.
There are numerous main factors for the occurrence of wrong parts:
1) The Tray Information Is Wrong
When the driver changes the material tray, if the material tray information is irregular with the
material number of the terminal in the system, it will certainly cause wrong parts.
2) Feed Tray Contamination
If other components stay on the tray, it might create the wrong component.
3) Human Procedure Mistakes
When replacing the tray, if the driver is not mindful, it might create the incorrect part.
3. Flying Pieces Trouble
The flying parts problem describes the elements got by the nozzle diminishing during the SMT assembly
procedure.
There are numerous major factors for the issue of flying components:
1) The Nozzle Is Clogged, or the Surface Mount Is Uneven
If the nozzle is clogged or the surface mount is irregular, it will impact the fit in between the nozzle
and the part, leading to flying parts.
2) Components Are Defective or Do Not Fulfill Standards
If the elements are defective or do not meet the criteria, it will also cause flying parts. So, the
selection of PCB component vendors also is considerable.
3) Support Pin Heights Is Irregular
If the support pin heights are irregular, the PCB board will certainly not have the ability to continue
to be level, resulting in flying components.
4) The Component Density Is Incorrectly Embeded in the Program
If the program establishes the incorrect element thickness, the spot elevation will be unreasonable,
leading to flying components.
5) The Spot Stress Is too High
If the patch pressure is expensive, it may cause the element to fly off.
6) Inadequate Solder Paste Viscosity
If the solder paste is not sticky enough, the components might diminish during the transfer of the PCB
board.
Summary
Typical issues in PCB SMT assembly will impact printed circuit top quality and making efficiency. For
that reason, printed circuit makers should reinforce the prevention and control of these problems during
the SMT manufacturing process.
Details measures include:
Do a great work of keeping and servicing the tools to prevent failure.
Strictly adhere to the procedures to stay clear of human operating errors.
Reinforce high quality examination of components to prevent incorrect and missing components.
Taking the above steps can successfully minimize issues in SMT spot production. And it can boost the
quality and production efficiency of circuit card.
