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SMT electronics assembly manufacturing forum.


assembly with/without TH components

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#79587

assembly with/without TH components | 9 January, 2018

Hi SMTnet, I'm newbie here and searching for information on a pcb reconvertion. So in order to reduce costs on a small pcb+ componentes+assembly I need your experience on assembling only SMT components vs SMT+TH; the point is actually my PCB has about 7 SMT componentes + 2 TH components (USB-A vertical receptacle + 3mm led). What would be the advantages (in assembly terms) to convert to all SMT? This change implies mecanical changes, will need a guide for SMT Led light, but no mecanical changes around USB. My doubt here is, will I have problems with long term fixing the USB rcpt to board (USB-A vertical receptacle) if not using TH fixations? I've seen a lot of that on cell-phones charging connectors. Thanks to all

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#79590

assembly with/without TH components | 9 January, 2018

The truth is that TH will give you better mechanical stability. If it is a part where you risk strip off the pads of SMT connector, don't make this transition to SMT. If it is a one time cable plug there and there will be not too much pressure, go for it.

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#79592

assembly with/without TH components | 9 January, 2018

> The truth is that TH will give you better > mechanical stability. If it is a part where you > risk strip off the pads of SMT connector, don't > make this transition to SMT. If it is a one time > cable plug there and there will be not too much > pressure, go for it.

Thanks for your reply Evtimov. About assembly costs I was doing some online simulations and found huge diferences (sometimes 50%) when comparing 7SMT+2TH and 8SMT+1TH. Is that normal(usual)?

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#79594

assembly with/without TH components | 10 January, 2018

Simulating with what? In developed countries manual labour is expensive but is also still the most common solution to fitting though hole parts, even if the board are then wave-soldered. Mixing SMT and THT on what sounds like a very simple product will make a far more considerable difference than on a board with 100's of SMT parts and a couple of THT connectors. Consider that by mixing technologies you are introducing 2 processes both of which will have an effective minimum time to process a board regardless of how many parts it involves. However with USB-A you probably don't have much choice.

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#79596

assembly with/without TH components | 10 January, 2018

Obviously the cost difference between only smt and smt+th is huge though TH only 1 components,they need different material,machines,tools and control methods,so if possible just use only smt process to assemble all components,but to verify if the usb can be fixed firmly,just design an experiment in which plug/unplug outer usb to/out of the usb fixed on pcb with smt process,for example,for 5000 times of plug/unplug in 1 week,

DaiShang

http://www.SMT-precise.com.cn

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#79597

assembly with/without TH components | 10 January, 2018

Thanks to all for your quick answers. I will do a prototype to test mechanical stability on USB-A, SMT version and will decide the next steps for there. Best Regards.

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#79604

assembly with/without TH components | 11 January, 2018

You might want to look at pin in paste. It is not very common but I have seen it work very well.

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