PCBA Tech - Steps for PCBA replacement parts recognition

"PCBA substitution material introduction" is an inevitable evil of production, and the timing of substitution material introduction usually falls on the need to undertake the design burden of the predecessors, and most of them are required to be completed immediately when time is tight, there are many restrictions, and information is lacking. .

Although we all suggest to stop this vicious cycle of substitute materials, it is best to import the second source at the first time of design, but due to various reasons, such as parts to be end of life (EOL, End Of Life), original design For reasons such as defects, primary source manufacturers' unwillingness to reduce prices, etc., it is always difficult to completely avoid PCBA products that are required to admit that alternative materials are required in subsequent mass production.

Since substitute materials cannot be avoided, there should be countermeasures to minimize the impact of substitute materials. The following are the qualification steps and precautions when Shenzhen Gracetech recommends the introduction of alternative materials. I believe that many large-scale companies also have similar introduction specifications for alternative materials. You are also welcome to provide your own experience and opinions:

Step 1: Do document review first:

Confirm that the electrical characteristics of the parts meet the design requirements.

Confirm that the mechanical dimensions of the parts will not interfere.

Confirm that the welding feet of the parts are consistent with the main parts, or the welding pads (pads) can coexist with the main parts, and will not cause welding quality problems.

Confirm that the parts will not affect the appearance.

Step 2. Request and test actual substitute material samples:

Check the appearance and confirm that the size of the parts meets the requirements of the drawing.

Solder the parts to the circuit board to confirm the solderability and test its electrical characteristics. It is best for PCB companies to establish a checklist or specification of test procedures recognized by parts for different parts. Shock), or drop testing, etc. Some even have to do long-term reliability testing.

Sometimes it is necessary to evaluate whether the parts need to be produced through SMT, instead of the engineer's own manual refueling, because some soldering strength will show a huge difference between manual welding and SMT welding.

Step three, small batch trial production (Control run):

Although it is called a small batch trial production, its purpose is to verify the mass production capacity of the parts vendor, so it is best to have a certain quantity, and 500~1000pcs is recommended. Because the quantity is too small, the PCB parts manufacturer may make samples by hand, or the parts manufacturer just selects parts with good specifications to send samples, and the quality of the parts produced in mass production in the future may be reduced.

Part suppliers are required to attach shipment inspection reports, including FAI (First Article Inspection) reports, to take precautionary actions.

It is recommended that the IQC of the PCBA electronic assembly factory should strictly inspect the incoming parts to reveal the problems that may cause quality loss in advance, because the quantity of 500~1000pcs after the production line is still a bit troublesome.

SMD parts must require tape and reel packaging, and the interval between each material in the tape should be consistent with the packaging of the main supplier, so that the SMT program will not be adjusted every time the material is changed. If there is no tape and reel packaging, at least it must be consistent with the packaging of the main raw materials.

It is recommended to have an engineer or assistant to follow during the trial production, because the work performed by the production line operators is to complete the work, because they have the pressure of the production line performance, even if there are problems with the parts, they will try to overcome them and continue production, But the purpose of trial production is to discover problems and respond to them. If no one follows, they will miss these opportunities to discover problems, which may cause future losses.

In addition, the import of "PCBA replacement parts" will mostly not be a normal task, so it will generally only be a temporary task group, where relevant personnel are selected by various departments to participate. Generally, it is necessary to integrate factory processes (Process) and R&D institutions (Mechanical). For engineering personnel such as R&D Electronics (Electrical), Quality Assurance (QA), etc., it is best to have a project manager (PM) to take the lead in monitoring the progress.

Just because "PCBA replacement parts import" is a temporary task grouping, most of each department will not send an army to do the task, because the first army is usually used to charge, but the knowledge required for replacement materials may sometimes be newer. The product is even more troublesome. If you have written a computer program, the introduction of alternative materials is like changing someone else's program, and sometimes it even far exceeds the energy input of writing the program yourself.

What are the characteristics of the engineering staff who implement the replacement material introduction?

Just because the later introduction of substitute materials has the following characteristics:

Quality pressure: Sometimes no one says anything about quality, but sometimes it must be a choice. So hard!

Time pressure: Due to the shortage or shortage of materials in the production line, PCBA replacement parts are urgently needed to resume production on the production line, and it is necessary to withstand finding replacement materials in the shortest time.

Design ability: Just because you have to bear the burden of predecessors, design and engineering capabilities with a certain amount of experience are necessary.

Carefulness: Carefulness is a must. You must be able to stand your temper, verify the alternatives step by step, read the previous stories, and sometimes humbly inquire about the history of the product design or production of the predecessors.

Personally, I would suggest that the meeting for the implementation of PCBA replacement material import should be held by the directors of each department, and then assigned to the following engineers to perform, so that it can be time-effective, and secondly, it can also give some discounts between departments.