Small-scale production of electronics in China, the personal experience of a layman
Being engaged in electronics "for the soul" and not claiming the laurels of "professional" and "specialist", however, sometimes you manage to create something interesting not only for yourself, but also for others. And here inevitably raises the question of the manufacture of small series. About the order of printed circuit boards have already been written many times, many have tried and, in principle, everything is less or less clear what and how. The first batch is sealed, stitched and given to happy owners, all is well. Suddenly, it turns out that a couple of dozen more boards have to be done, and especially no time to sit in the evenings with tweezers and a hairdryer, and my eyes are pitiful. The time has come to take the next step - try the PCBA service (PCB Assembly).
This article will discuss the previously described adapter designed for simraising enthusiasts. The article is not a marketing research, I describe my personal experience.
To begin, let me remind you that you need to order the manufacture of bare printed circuit boards. If you already have a divorced board, you need to export the Gerber and Drill files. For each PCB layer, a separate Gerber file is needed. The name of the gerber file should correspond to the PCB layer. I use DipTrace for layout of boards and when exporting Gerber files, files with the following names are created:
BoardOutline.gbr
Bottom.gbr
BottomMask.gbr
BottomPaste.gbr
BottomSilk.gbr
Through.drl
Top.gbr
TopMask.gbr
TopPaste.gbr
TopSilk.gbr
It would seem clear enough? But with such file names, the archive will only accept SeeedStudio. For all other files you have to rename:
Top layer: pcbname.GTL
Inner Layer 1: pcbname.GL1 (for 4-layer board)
Inner Layer 2: pcbname.GL2 (for 4-layer board)
Bottom layer: pcbname.GBL
Solder Stop Mask top: pcbname.GTS
Solder Stop Mask Bottom: pcbname.GBS
Top Paste: pcbname.GTP
Bottom Paste: pcbname.GBP
Silk Top: pcbname.GTO
Silk Bottom: pcbname.GBO
NC Drill: pcbname.TXT
Outline layer: pcbname.GKO or pcbname.DO
Please note that when ordering printed circuit boards, solder paste layers are usually not exported, but when ordering PCBA, they will be useful to us. Also do not forget to export the Drill file.
We also need a BOM (bill of materials) and a pick-and-place file, which can also be exported from DipTrace (or the software you are using). Moreover, BOM can be made from a pick-and-place file, grouping the same positions and excluding those positions that you do not plan to mount. For example, I provided a place to install the JTAG connector, but the connector itself was soldered only to the board used for debugging.
The format of a BOM file is different for everyone, but the following fields should almost always be present:
1. Quantity
2. Manufacturer
3. Partnamber manufacturer
For the Makerfabs service, where I eventually ordered the build, I made this BOM file:
Requirements may vary, so it is best to check this point in advance.
Also do not forget to check the Design Rules / PCB capabilities. As a rule, most services allow you to download ready-made files for frequently used software, but for DipTrace you need to check everything manually. On the other hand, with the rules that go out of the box in DipTrace, most of the offices for the production of printed circuit boards cope with the stock.
With a small print run (10-20 pieces) it is quite possible that the components on the board will be arranged manually. You need to make sure that marking of all components on the board corresponds to a BOM file, even if you have a pick-and-place file, where the location of each component is also indicated.
Suppose you coped with this, then you need to do the following. First contact the service and ask them to send the cost calculation for the project, sending them gerberas, drill file, BOM and pick-and-place. Usually the answer comes within one or two days. Carefully look at the cost of the positions. The account will include the following items:
- Manufacturing of printed circuit boards
- Making a stencil for applying paste to the board
- Selection of components from among local analogues (*)
- Installation and testing (**) (***)
- Shipping
(*) - allows you to reduce the cost of the board by replacing the original components with local ones, but also not for free, it cost me $ 20. The selection fee is a one-time fee, when re-ordering the same design is not charged.
(**) Testing procedure can be discussed in advance, in small companies they can fulfill any whim, of course, not for free.
(***) If you order a small batch - a small commission for small print runs may be added, for example, from Makerfabs - with a batch of less than 20 pieces.
Making a stencil is also, in general, a one-time procedure, you do not need to pay for re-ordering, the Chinese promise to keep them.
Pay special attention to the shipping method. Small offices often do not have experience working with the Russian Federation; they may, with best intentions, suggest using some kind of courier service, the name of which you will have little to say. At the same time, this courier service in the territory of the Russian Federation can work through, say, some EMS. And you suffer with him solely through your own fault ...
Again, do not forget to specify the taxpayer number (TIN) and ask the Chinese to indicate it on the address form, so as not to get problems from our customs. The Chinese may also ask, indicate the price on the box completely or understate it. I asked to specify in full, taxes from this amount are not charged yet.
After the cost is agreed upon and the order is paid, the manufacturing stage usually takes 1-2 weeks. At the end of the stage, you can ask to send you a photo of the result so that it is not boring to wait during the delivery :) Also ask for a report on how the boards passed the testing agreed with you. If all is well - wait, comesoon .
In general, the order processing cycle looks like this:
If you compare the cost of the assembly itself and the assembly to order, then the question rests primarily on how much you estimate your time. Personally, I am collecting a fee like at the KDPV somewhere in an hour or more. 10 boards - conditionally two working days. Comparing the cost of their working time and the cost of contract assembly - the second is cheaper to me. Especially, if we are not talking about 10 boards, but, say, about 50-100 pieces. Yes, there are specially trained installers who do it much faster and better. But this is not about me ...
When exactly you should not use the contract assembly? For example, if you are not completely sure that your design is fully functional. Because this is solely your problem, the collectors are not responsible for this and the order will be fully assembled regardless of its efficiency. Well, at the end of January, too, should not be ordered. The order made after January 20 you will see only in the middle of March. Because all of China celebrates the new year ...
Regarding intellectual property leakage - the service declares the untouchability of your intellectual property. How this immunity will be guaranteed is not very clear, but for open-source or hobby projects this is not so important. In the end, for electronics hobbies, circuits are usually quite simple, but the firmware may not be provided for testing. But it is up to you.
This article will discuss the previously described adapter designed for simraising enthusiasts. The article is not a marketing research, I describe my personal experience.
To begin, let me remind you that you need to order the manufacture of bare printed circuit boards. If you already have a divorced board, you need to export the Gerber and Drill files. For each PCB layer, a separate Gerber file is needed. The name of the gerber file should correspond to the PCB layer. I use DipTrace for layout of boards and when exporting Gerber files, files with the following names are created:
BoardOutline.gbr
Bottom.gbr
BottomMask.gbr
BottomPaste.gbr
BottomSilk.gbr
Through.drl
Top.gbr
TopMask.gbr
TopPaste.gbr
TopSilk.gbr
It would seem clear enough? But with such file names, the archive will only accept SeeedStudio. For all other files you have to rename:
Top layer: pcbname.GTL
Inner Layer 1: pcbname.GL1 (for 4-layer board)
Inner Layer 2: pcbname.GL2 (for 4-layer board)
Bottom layer: pcbname.GBL
Solder Stop Mask top: pcbname.GTS
Solder Stop Mask Bottom: pcbname.GBS
Top Paste: pcbname.GTP
Bottom Paste: pcbname.GBP
Silk Top: pcbname.GTO
Silk Bottom: pcbname.GBO
NC Drill: pcbname.TXT
Outline layer: pcbname.GKO or pcbname.DO
Please note that when ordering printed circuit boards, solder paste layers are usually not exported, but when ordering PCBA, they will be useful to us. Also do not forget to export the Drill file.
We also need a BOM (bill of materials) and a pick-and-place file, which can also be exported from DipTrace (or the software you are using). Moreover, BOM can be made from a pick-and-place file, grouping the same positions and excluding those positions that you do not plan to mount. For example, I provided a place to install the JTAG connector, but the connector itself was soldered only to the board used for debugging.
The format of a BOM file is different for everyone, but the following fields should almost always be present:
1. Quantity
2. Manufacturer
3. Partnamber manufacturer
For the Makerfabs service, where I eventually ordered the build, I made this BOM file:
References Qty Description Manufacturer MPN Digikey Mouser RS Newark Farnell
25/27 1 90131-0123 WM8121-ND 538901310123 6703443 60H4442 2381222
C1-C2 2 22pF,0603 C0603C220J1GACTU 399-7874-2-ND 80C0603C220J1G 8015350 75R1532 1813429
C3-C4 2 100nF,0603 C0603C104K5RACTU 399-5089-2-ND 80C0603C104K5R 8015347 72J5992 1692286
C5 1 4.7uF,0603 CL10A475KL8NRNC 1276-6794-6-ND 81GRM188R60J475ME9D 6911155 62W5999 2211163
...
Requirements may vary, so it is best to check this point in advance.
Also do not forget to check the Design Rules / PCB capabilities. As a rule, most services allow you to download ready-made files for frequently used software, but for DipTrace you need to check everything manually. On the other hand, with the rules that go out of the box in DipTrace, most of the offices for the production of printed circuit boards cope with the stock.
With a small print run (10-20 pieces) it is quite possible that the components on the board will be arranged manually. You need to make sure that marking of all components on the board corresponds to a BOM file, even if you have a pick-and-place file, where the location of each component is also indicated.
Suppose you coped with this, then you need to do the following. First contact the service and ask them to send the cost calculation for the project, sending them gerberas, drill file, BOM and pick-and-place. Usually the answer comes within one or two days. Carefully look at the cost of the positions. The account will include the following items:
- Manufacturing of printed circuit boards
- Making a stencil for applying paste to the board
- Selection of components from among local analogues (*)
- Installation and testing (**) (***)
- Shipping
(*) - allows you to reduce the cost of the board by replacing the original components with local ones, but also not for free, it cost me $ 20. The selection fee is a one-time fee, when re-ordering the same design is not charged.
(**) Testing procedure can be discussed in advance, in small companies they can fulfill any whim, of course, not for free.
(***) If you order a small batch - a small commission for small print runs may be added, for example, from Makerfabs - with a batch of less than 20 pieces.
Making a stencil is also, in general, a one-time procedure, you do not need to pay for re-ordering, the Chinese promise to keep them.
Pay special attention to the shipping method. Small offices often do not have experience working with the Russian Federation; they may, with best intentions, suggest using some kind of courier service, the name of which you will have little to say. At the same time, this courier service in the territory of the Russian Federation can work through, say, some EMS. And you suffer with him solely through your own fault ...
Again, do not forget to specify the taxpayer number (TIN) and ask the Chinese to indicate it on the address form, so as not to get problems from our customs. The Chinese may also ask, indicate the price on the box completely or understate it. I asked to specify in full, taxes from this amount are not charged yet.
After the cost is agreed upon and the order is paid, the manufacturing stage usually takes 1-2 weeks. At the end of the stage, you can ask to send you a photo of the result so that it is not boring to wait during the delivery :) Also ask for a report on how the boards passed the testing agreed with you. If all is well - wait, come
In general, the order processing cycle looks like this:
If you compare the cost of the assembly itself and the assembly to order, then the question rests primarily on how much you estimate your time. Personally, I am collecting a fee like at the KDPV somewhere in an hour or more. 10 boards - conditionally two working days. Comparing the cost of their working time and the cost of contract assembly - the second is cheaper to me. Especially, if we are not talking about 10 boards, but, say, about 50-100 pieces. Yes, there are specially trained installers who do it much faster and better. But this is not about me ...
When exactly you should not use the contract assembly? For example, if you are not completely sure that your design is fully functional. Because this is solely your problem, the collectors are not responsible for this and the order will be fully assembled regardless of its efficiency. Well, at the end of January, too, should not be ordered. The order made after January 20 you will see only in the middle of March. Because all of China celebrates the new year ...
Regarding intellectual property leakage - the service declares the untouchability of your intellectual property. How this immunity will be guaranteed is not very clear, but for open-source or hobby projects this is not so important. In the end, for electronics hobbies, circuits are usually quite simple, but the firmware may not be provided for testing. But it is up to you.
Source: https://habr.com/ru/post/409657/