Last time Angell and Lesley elaborated the most basic and frequently asked questions about PCB Assembly. And today we’ll focus on some details.
This time we invited Aimee, another our senior customer service staff, to our Channel. Hope her professional answer can help you know our PCB Assembly service better.
Q1：Aimee, working in a PCB Prototype company, we’ll inevitably meet some urgent orders. For PCB order, our customers can choose extra urgent service to meet their needs. Then do we also offer expedited service for PCB Assembly?
Aimee: Sure, we can expedite assembly service when all components are ready. For components procurement, it normally takes a certain time and process. so The room to speed up this process is little.
Q2: When placing an order, some makers may have ideas like: I want blank PCBs and components separately for 5pcs and another 5pcs assembly completed. So can it be achieved?
Aimee: There is no problem to choose different quantity for PCBs and assembled boards, but the PCB quantity should be larger than assembled boards. The number of PCB and the number of PCBA are not necessarily the same, but the MOQ for PCB is 5 and no MOQ for assembled boards.
Q3: For PCB or PCBA service, we provide 3 kinds of flexible options for part supply. They’re PCBWay supply parts; Customer supply parts; and You supply some parts we do the rest. Then what issues are important for customer-supplied parts?
Aimee: There are 3 aspects.The 1st one is Markings. Each packaging should include part number, package, value information same as the ones in BOM. It’s better to add designators to each packaging if you can. If there is anything different from information in BOM, please remember to contact us to correct BOM in advance.
The 2nd one is Parts Overages. You know, we must prepare some extra components to prevent the unnecessary part damage or loss. For Resistors, Capacitors and Diodes with the following packages - (0603, 0805, 1206, 2225, SOT, SOD, MELF ), the required minimum quantity is 50 pieces including 30 pieces extra over assemble quantity. For example, if the assemble quantity is 40 pieces, 40 plus 30, then we will need 70 pieces in total. For Resistors, Capacitors, Diodes with other types of packages - (0201, 0402, mini Melf, miniature packages) , the required minimum quantity will be 100 pieces including 50 pieces extra over assembly quantity. For example, if the assemble quantity is 80 pieces, then we will need 130 pieces. As a means of improving efficiency and security, a small number of excess is also requested for expensive parts such as IC, BGA, QFP, Connectors, etc. And the quantity can be 1-5 pieces based on the total quantity of assemblies.
The last one is the Packaging of Parts. Based on our experience, here’s some advice. SMT parts that are not supplied on reels should be on one continuous strip of tape. If there’s a need to assemble the same SMT part on different boards, please keep them in the continuous strip of tape or on the reels. Do not cut them into strips. Furthermore, Components on the tube or tray are good for assembly as well.
Q4: Aimee, it’s a common situation that sometimes we cannot find some components due to uncontrollable factors. Under this circumstance, will we recommend substitutes in the quotation?
Aimee: Sure, it’s a part of our job. If our customers accept to use substitutes for assembly, then you can list a column of substitutes (Yes or No) in BOM. At the same time, the detailed specification of components can help a lot. Don’t forget to write it down in the BOM file.
Q5: Aimee, what will happen when the Infos in Centroid file and BOM file are different? I know sometimes the parts are not soldered just because the BOM file doesn’t cover some info which is on the relative Centroid file.
Aimee: Normally we purchase and solder the parts just based on your BOM file. And centroid file is just used to confirm the position of each parts, so it is important to make sure that BOM list includes all the parts you need.
Q6: Then after assembly, are there any tests to make sure everything works well?
Aimee: Of course yes. Normally we will do AOI test after assembly.
As for IC or BGA area, we can do X-ray tests if there’s a request from our customers. And the test result will be provided to them for review. What’s more, we suggest testing the LEDs after assembly when your components include some. Cause if not, generally the result will contain around 2% failure.
Q7: What documents are needed for testing service?
Aimee: There are 3 different situations.
For LED testing, we’ll require them to send us the testing procedures with pictures showed.
For the function test, the test methods are needed, including the test steps and pictures. Moreover, it will be better if there’s any test video for reference. Oh, our assembly factory only has the conventional universal meter, so please send us the specific test tools when it’s necessary to test your project.
For both LED testing and function testing, the test fee will be confirmed and charged after testing, which is calculated according to the time used.
Q8: Aimee, can we program for our customers when the assembly and test is completed？
Aimee: Yes, we can program some parts. If you have this need, just let us know which parts in the BOM you need us to do programming, and send us the relevant boot loader files, which usually is .hex file. Then our engineer will check whether we can do it and quote for the extra programming fee.
Q9: Can you explain deeper about the IC programming?
Aimee: Sure, IC programming will be performed before the chips are mounted on the board. You can contact with your own customer service for details. Besides, we also have a qualified programming management system. We understand the importance of Intellectual Property (IP). We will sign a Non-Disclosure Agreement (NDA) document on the request of the customer in order to protect IP rights.
Q10: Quite professional. The next question, will we send pictures to our customers for review?
Aimee: Another good question. During the manufacturing process, PCBWay will send sample pictures to you to confirm everything is correct. But please note that we just put the PTH parts on the position and the PTH parts are not soldered yet. If customers find any position or direction problems, we can make easy correction .After customers confirm the sample picture, we will finish the soldering for PTH parts.
Q11: Once the sample picture is confirmed, how long will it take to ship out the assembled PCBs?
Aimee: It depends. Because there’s a difference between orders, like assembly quantity, PTH components quantity, and whether there are special procedures or not. But I can tell an approximate duration. If it’s a prototype order, it usually takes 3 working days; For small and medium quantity orders, it usually takes 3 working days; And if there is a special requirement like con-formal coating and function testing, we need to check the complexity to confirm the final lead time.
Q12: Will you ship the stencil back to our customers when the assembly is finished?
Aimee: Usually we will not ship the stencil back to you,it will be stored in our warehouse for the use of repeat order in the future. If you really need it, the SMD-stencil can be shipped to you too,while you have to pay for the extra shipping cost. The stencil with framework is much heavier than PCB. When shipped, it adds a lot of weight.
Q13: After receiving the boards, what to do if there are any defects?
Aimee: You're always encouraged to contact our after-sales team at any time and use the pictures or videos to show the issue .
And it'll be better that you can analyse the reason to help us to solve problem soon.
If the problem is related to components, apart from the part NO., please tell the relevant designators in the bom too.
BTW, please do not repair the defective boards by yourself before we confirm the real reason .
If you have any questions about your orders, just leave a comment below or send a message to feedback@pcbway.com.
Project Planning：Simon
