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Seeed Fusion PCB Assembly Service Quick Questions


Q. What are the PCBA Open Parts Libraries?  

A. The Open Parts Libraries (or OPLs) are a catalog of locally sourced parts that are more affordable and more importantly, have a much shorter procurement time compared to imported components from outside of China. By sourcing all components from these OPLs, the PCBA production time can be reduced to just 7 working days. See how the lead-time is affected here. There are also ongoing component libraries for these components that have been prepared by Seeed and the wider community. View the libraries here.

Q. What is the difference between the Seeed and Shenzhen Open Parts Libraries?

A. The Seeed OPL is part of Seeed's internal stock of components. We buy these in bulk quantities and maintain the stock in our own warehouse so we can just pick and solder the parts once the PCB boards are ready. But the variety is limited since we are unable to maintain so much stock in our warehouse.

The Shenzhen OPL is a new addition to the PCBA OPLs that expands the variety of components to over 15,000 options. The stock is maintained by our partner, Shenzhen's leading and internationally recognized parts distributor who sources directly from mainland Chinese factories and other distributors. Parts from the Shenzhen OPL can be procured in just a few days, faster than the production times for most PCB orders. So by using parts from the Shenzhen OPL (so long as all parts are from the PCBA OPLs), the PCBA production time can also be reduced to 7 working days. For more details, please refer to this post.

Also, please note that the Shenzhen OPL has higher minimum order requirements for certain components. Even if you only need one component for your order, if the minimum order quantity is 50 pieces, then we will have to buy 50 pieces and 49 pieces will go to waste.

Q. Can I include both OPL and non-OPL components in my BOM?

A. Of course, why not? You can even enter the Seeed SKU directly for the MPN in the BOM file. However, the production time will still be 20 working days if non-OPL parts are needed.

Q. Can I send you the components directly?

A. In some cases, but it is not recommended. You will need to pay for the shipping and any customs fees, and we will not be held responsible if they are lost before they get to us (it happens). Please contact us directly for a quote.

Q. What kinds of components cannot be sourced by Seeed?

A. There are three main cases where we will not be able to source the components:
  1. Restricted materials that cannot be imported into Mainland China due to Government regulations.
  2. Components that cannot be purchased in small quantities or in the required amount.
  3. Components that are out of stock or have an indefinite lead time.

Q. Can I purchase parts from the Open Parts Library directly?

A. Unfortunately not, we are not licensed to sell these parts separately. Sorry about that.

Q. What is the minimum order quantity (MOQ)?

A. For PCBs, the minimum order quantity is 5 pieces, but for PCB assembly, you can choose to have as little as a single piece populated. We will send you the remaining bare PCBs with the rest of your order.

Q. Can you start components procurement first, then I will place the order later to save time?

A. No. We have to be sure of all the components on the boards before we begin procurement. If you suddenly decide you don’t want the order or you want to change some of the components, then we have to start again, and you won’t save time. So please make sure all the details, including the PCB design, are complete and correct at the time of placing the order.

Q. Is it really free shipping anywhere around the world?

A. Yes! For any shipping method available for your country, shipping for PCBA orders is completely free! It doesn’t matter if it would normally cost $30 or $100. But it does not count if you add other Seeed Fusion orders to the shipment besides PCBA.

Q. Do I need to place an order for the SMT stencil if I place a PCBA order?

A. Nope, that is included in the cost of PCBA orders under ‘Consumables’. We will not send the stencil to you afterward, however. If you want a stencil as well, please place an order for these separately.

Q. Will I get a stencil with my PCBA order?

A. No, sorry. Due to the large size of the stencils we produce for PCBA orders, shipping them is expensive and so we will not ship them. Smaller designs may also have the data for multiple orders combined onto one stencil.

Q. Can I save on engineering fees when ordering the same assembled boards again? (Non-recurring engineering fees or NRE)

A. Nope, sorry. Each order is processed independently, and due to the large volume of orders, we cannot afford to keep the materials like stencils for long periods of time after the initial run. Many processes depend on the quantity, so even if you place the order again but for a larger batch, the old stencil and engineering procedures may not be appropriate for the larger quantity. Exceptions apply for test jigs.

Q. What happens to the stencils afterward?

A. We will make sure they are disposed of responsibly, don’t worry.

Q. Do you use the pick and place machine on all orders?

A. No. Whether we use the pick and place machine depends on the number of boards in your order, the number of SMT components per board and the number of different SMT parts. Ultimately, it is up to the engineer’s judgment. Loading and setting up a pick and place machine can take a long time, possibly much longer than actually populating the boards. And if there are only a few boards, it does not make sense to set up the pick and place machine if the boards can be completed by hand in the same amount of time or quicker. We have an experienced team of technicians for hand placing SMT components and are dedicated to dealing with a large volume of low quantity orders, so rest assured the quality will be impeccable.

Please also note that the XY/Pick and Place/Centroid files can only be read by machines. The technicians cannot read them so you'll still need to provide assembly files or silkscreen markings on the boards to indicate placement and polarity.

Q. Do you use the x-y or pick and place file for all orders?  

A. If you can provide it, that would be great. It doesn’t mean we will definitely use it, but it is good to have in case of special circumstances. E.g. It is helpful if there are a large number of 0201 size components. For more information on how to export these, click here.

Q. Do I need to have silkscreen on the PCB boards for PCBA?

A. Not really, but we need to know where the components need to go. So please include an assembly file or a clear diagram showing us how the assemble the boards in the PCB upload. Many design programs can generate some kind of assembly layer in Gerber format, but a PDF file is also fine. Please make sure it contains all the necessary information like markings for polarised components.

Q. Can you solder on both sides of the boards?

A. Yes, no problem. For large SMT components, glue dots will be applied to hold them in place during reflow soldering, but usually, the surface tension of the solder can hold smaller components in place, or a reflow tray can be used to block the flow of air and stop the solder on the bottom side from reaching the reflow point.

Q. Should I use through-hole or surface mount components?

A. Through-hole components are not suited for automated soldering in small quantities, so nearly all through-hole components are soldered by hand. We advise you to use through-hole components only when necessary so we at least have the option of using the pick and place machine, which can be quicker for larger batches (see above question). If there are a large number of through-hole components on a board, we may ask for additional charges since this will take up a lot of time and all the wire bending and cutting will make our technicians’ hands sore!

Q. What solder paste do you use in the assembly line?

A. All our assembly lines use lead-free solder, but to ensure RoHS compliance, please make sure your materials, including printed circuit boards are also RoHS compliant.

Q. I am submitting a panel, not an individual board. How should I fill out the order form?

A. On the order form, one piece is defined as "Whatever is uploaded in the Gerber files", be it different designs or a panel of 300 boards. So for example, the panel of 300 boards would still be considered as one piece. If the quantity is selected as 5 then, in the end, you will get 1500 individual pieces. Therefore, it follows that the BOM file needs to account for each 'piece' as well. Simply multiply the quantities of each component on one sub-board, by the number of sub-boards. 

For example, a panel of three boards of the same design has components R1 and C1 per sub-board, where there are two of R1 on one board:

Q. I would like some boards on a panel to have different parts assembled/some not assembled. How should I fill out the order form?  

A. You can do this by changing the designator name on the boards and BOM so it is treated as a different part. 

Example 1:  

If you need an IC to be soldered on one board but not the others, then you can call it IC1 on one board and IC2 on the others, and then do not include IC2 in the BOM. Please note that you will need to select the appropriate number of different designs on the PCB section, as the boards are no longer exactly the same.

Example 2:

Resistors R1, R2 and R3 have different values but the circuitry is the same. Then they should be labeled individually on the boards and BOM. Since the designators are now different, the number of different designs is 3.

Q. I need CE / FCC / RoHS / certification for my PCBA. Can you help me with that?

A. If you intend to sell your device commercially in certain regions, you may be required by law to obtain product certifications. For many countries in the European Union and some other countries, CE is required. For North America, FCC is required. Both are similar in that they ensure that the devices are safe for consumer use. By default, PCBA devices assembled at Seeed do not come with any such certification. Some can be self-proclaimed, others can only be performed by qualified third-party laboratories and may take weeks and thousands of dollars to test.

At Seeed, our engineers can help you go through this process. Inquire as part of the DFX service via

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Last Modified 2021/1/03

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