First article inspection is the inspection of one to three pieces from the start of the production run.
The PCB first article inspection process is an important step in the assembly of your circuit board as the CM inspects it very closely for accuracy.
The First Article refers to the first PCBA processing assembly board that meets the quality requirements of patch processing and welding.
The first finished board in the first batch of each new model is named “First Article ” in the SMT processing plant.
Compared with subsequent products, the First Article is not only an actual inspection of product performance but also a quality inspection of engineering processes.
So what are the welding and testing contents of the first PCB assembly board?
How to Check First Article PCB Assembly Quality
1. The first PCBA assembly board welding
Place the surface assembly board that has passed the mounting and inspection on the mesh conveyor belt or chain guide rail.
And the surface assembly board slowly enters the furnace with the conveyor belt at the set speed.
It passes through the:
- Heating zone,
- Heat preservation zone
- Recirculation zone and
- Cooling Zone,
- Complete reflow welding
Take out the surface assembly board at the exit in time. Wear an anti-static wrist strap during operation.
2. Inspect the welding quality of the First Article assembly board
(1) Inspection method of PCB board
The welding quality of the First Article assembly board is generally inspected by visual inspection.
According to the assembly density, choose 2~5 times magnifying glass or 3~20 times microscope for inspection.
(2) Inspection content
① Check whether the soldering is sufficient and whether there are traces of insufficient melting of the solder paste.
②Inspect whether the surface of the solder joint is smooth, whether there are hole defects, and the size of the hole.
③Check whether the amount of solder is moderate, and whether the shape of the solder joint is half-moon.
④Check the amount of solder balls and residues.
⑤Check the defect rate of tombstones, virtual soldering, bridging, component displacement, etc.
⑥Check the color change of the PCB surface, and allow a little but even discoloration of the PCB after reflow soldering.
(3) First Article Inspection Standards
According to the corporate standards established by the unit or refer to other standards. Currently, IPC-A-610E is mostly used.
Adjust the parameters according to the welding quality inspection results of the First Article assembly board.
When adjusting the parameters, the parameters should be carried out one by one to facilitate analysis and summary.
- First, adjust (fine-tune) the speed of the conveyor belt, retest the temperature curve and perform trial welding.
- If the welding quality cannot meet the requirements, adjust the temperature of each temperature zone until the welding quality meets the requirements.
What is Meant by First Article Inspection
The first article control also called FAI or DVI. It makes it possible to verify that the manufacturing process is able to produce parts in series according to the specifications, according to the customer’s request. The FAI is applied:
- The first batch of each component manufactured for the first time by the supplier.
- Whenever the manufacturing method or process is changed.
- In the case of a particular request appearing on an order.
The FAI control of a part must verify that 100% of the characteristics and parameters appearing on the drawings or in the associated specifications are respected.
For an FAI control, there can be several types of control:
- Documentary management (material conformity, etc.)
- Visual control
- Simple dimensional control and three-dimensional control.
Recognize the Quality Control in First Article PCB Production
Awareness of quality inspection in PCB production
① Awareness of the purpose of quality inspection in PCB production.
Find and eliminate errors in the SMT patch assembly process to achieve good process control and improve product yield.
② Awareness of the role of quality inspection in PCB production.
Find defects early to prevent defective products from flowing to the next process and reduce repair costs; discover defects in time, deal with them in time, avoid scrap products, and reduce production costs.
③ Awareness of quality inspection methods in PCB production.
Speaking of methods, PCB quality inspection methods mainly include the following:
Visual Inspection:
Directly observe and check the quality of the First Article with human eyes.
In the actual PCB production process, there are visual inspection procedures after:
- Printing paste printing
- Patching
- Reflow soldering
- Wave soldering and online inspection
They are PCB printing visual inspection,post-furnace comparison visual inspection, assembly visual inspection, and quality inspection.
Its characteristics are: low cost and the inspection effect is related to the PCB mounting density.
In the case of low-density mounting, the reliability, accuracy, and continuity of inspection vary from person to person.
In the case of high-density mounting, the reliability, accuracy, and continuity of inspection are generally reduced, and the inspection time is correspondingly longer.
Quality Control in First Article Production
- Establish a document system for quality control in First Articleproduction;
- Establish a PCB quality inspection system;
- Formulate PCB quality inspection standards;
- Develop operating specifications for visual inspection, AOT inspection, ICT inspection, and FCT inspection;
- Guidelines for the use of standardized testing equipment (AOI tester, ICT tester, and FCT tester);
- Develop inspection record forms or labels;
- Precautions for standard equipment operation.