The Chinese circuit board giant JLCPCB offers free SMD assembly for boards ordered there - we had to test that immediately.
If you are short of cash and can wait two weeks, you can order your circuit boards from Chinese suppliers - they are simply unbeatable there. If you have 5 or 10 identical boards, you can get half a euro card (100mm x 80mm, double-sided) often for less than one euro each.
The Chinese circuit board giant JLCPCB is now offering free SMD assembly for circuit boards ordered there - that is to say: Of course, the components cost something (literally: the price level is usually well below that of the local wholesalers), but machine assembly is not calculated. The minimum order quantity is 5 pieces; JLCPCB generously distributes coupons for first-time customers, eliminating the one-time costs for machine set-up (US $ 4).
What you have to do: tick the order and at the same time upload a parts list (BOM, Bill of Materials) and a table with the component positions (CPL, Component Position List) in Excel format with the Gerber files for the layout. However, the Excel table should correspond to the manufacturer's specifications; sample templates can be found on their website. Only one-sided assembly is currently possible.
The position list from the layout program (often a CSV text file) must first be imported into an Excel table. Please note that the component positions must be specified in millimeters and with a decimal point, the cells should be formatted as "text". The rotation of the component is somewhat critical : 0 ° means that the component does not have to be rotated as it comes off the roll. However, the manufacturer's processing software is clever enough to correct the component rotation based on the printed circuit board if necessary.
If everything is correct, you will receive a preview of the circuit board and the component positions before submitting the order. If they do not converge with the layout shown, it is better to try again after revising the CPL table, otherwise, an "engineering fee" (4 to 7 US dollars) may be due.
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| If the data is correct, the previews for layout and assembly should be congruent. |
When designing the circuit board, you should only use components that the supplier has on the machine at all times - other (stored) components are considered "extended parts" and cost a small extra fee. For example, the popular ATmega328PA (price: 1.79 US dollars for 10 pieces) is a "Basic Part", while the ATmega168PA is an "Extended Part". The resistors and ceramic capacitors in the types 0402 to 1206 are usually (except for crooked values) "Basic Parts" (price example for a purchase of 100 pieces: 100n capacitor 0.4 US cents, 74HC164 shift register 6 US cents).
The order numbers of the components with the specified information on the footprint (housing design) must be in the CPL list anyway, so you should look for the components beforehand from the JLCPCB inventory. Then everything goes very quickly: Upload BOM and CPL, check the preview and send the order. As shipping methods, JLCPCB offers the options DHL Express (expensive, but extremely fast and reliable) and EuroPacket, whereby the latter goes through a European shipping center for customs clearance before shipping and arrives a few days later (the package is then 6 to 8 days on the way). The final invoice amount already includes the customs duties, you can pay conveniently with PayPal.
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| Almost two weeks after ordering, we received our assembled sample boards |
Our double-sided sample boards were of good quality, carefully assembled, and soldered; Positions not specified in the CPL / BOM are simply left unequipped (important for manual replenishment: pads are bare and do not have any soldering tin on them). It is also worth mentioning that different solder mask colors are available at no extra charge and the tinning is led by default (can be switched to lead-free as an option). The latter should be irrelevant for home users who are still led because of nicer soldering points.
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