Author Topic: JLC PCB Prototype Assembly - Incredibly Cheap  (Read 44519 times)

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Offline DBecker

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Re: JLC PCB Prototype Assembly - Incredibly Cheap
« Reply #150 on: February 09, 2020, 02:38:25 pm »
I'm getting close to trying this service, so I've written a KiCad plugin that will generate the correct BOM and placement files with a single click, and without having to edit any of the standard outputs.

https://github.com/essele/kicad_jlcpcba

You need to add an LCSC attribute to the components in the schematic with the LCSC part number, then everything else should be taken care of. Extra rotations needed are in the rotations.cf config file ... I blatantly stole the ones in there from somewhere else and have then updated with specifics from the board I'm experimenting with ... these are footprint rotations rather than component rotations, which seems to work fine. They are far from complete.

CAVEAT LIST:

1. I'm not a python programmer (which will probably be evident from the code), this is a rough translation from a perl version, but seems to work ok.
2. I've never written a KiCad plugin before, so this is probably horrible.
3. There isn't a lot of error checking, it seems to work fine for my test board, but I'm sure there will be lots of failure scenarios.
4. I've only tested it on OSX .. don't know if it will work ok on Linux or Windows.
5. I haven't actually ordered any boards with this ... please examine the placement view on JLCPCB very closely before committing.

It it's of use, then I'll put some more effort into tidying etc.

Don't promote this until you have tried out a range of parts.  You don't need to order the boards, but at least check their board visualization tool.

Basing rotation on the footprint alone is *not* correct.  It needs to be based on the part type as well, with the possibility of over-ride when that does not work.  Compare the 0-degree orientation of a tantalum caps, electrolytic caps, and diodes.
 

Offline essele

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Re: JLC PCB Prototype Assembly - Incredibly Cheap
« Reply #151 on: February 09, 2020, 04:56:09 pm »
Thanks DBecker.

I did post it with the expectation that other people could experiment, feedback, and help improve it -- it's far from perfect (as per my long list of caveats)

I was definitely a little hasty, as in my efforts to check what you've suggested I have discovered that it doesn't work for the top side of the board, I'm sure it won't be a complex fix.

In any case, I've just checked a few polarised caps and diodes and (so far) they all seem absolutely fine with no rotation [not correct, see below]. Do you have any examples to hand that you know are wrong?

Also on the footprint vs part ... I probably don't understand enough about how this works, do you have some examples that I could test against?  The code to add per device rotation would be really simple, but I'd like to see some real world examples to test against.

EDIT: top fixed, but you are correct about the caps ... diodes all seem fine with no rotation,  but both electrolytics and tants (at least the ones I've looked at) do need 180 rotation -- I will do some experimenting.
« Last Edit: February 09, 2020, 05:26:19 pm by essele »
 
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Offline nigelwright7557

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Re: JLC PCB Prototype Assembly - Incredibly Cheap
« Reply #152 on: March 01, 2020, 08:05:04 pm »
JLCPCB are so fast I get the item on Monday and two days later I get an email telling me they are on their way !
 

Offline MarkR42

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Re: JLC PCB Prototype Assembly - Incredibly Cheap
« Reply #153 on: March 03, 2020, 08:12:43 pm »
Esselle, thanks for doing that, I've tried it with jlcpcb's viewer,

I updated the code to make it work on Kicad-nightly, and I've updated the rotations.

Diodes - were already good.
SON packages - were ok
sot23 - ok

Only my qfn part had the wrong rotation. So not bad for a first try.

I'll proably be ordering a board later in the year, their prices seem insanely low,

My tiny board is slightly too small for their minimum size, I tacked on an unused section for testing, but if I want to do a short production run I will panelise the boards 2 boards per panel
 

Online up8051

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Re: JLC PCB Prototype Assembly - Incredibly Cheap
« Reply #154 on: March 14, 2020, 01:49:00 pm »
I tried to preview my PCB projects  for SMT assembly in JLCPCB but I always have offsets between element and footprint.
I prepered very simple project but preview is still wrong.
[attach=1]

Different ways to generate Gerbers and P&P files do not change situation.
Does anyone know a solution for this problem?

I tried support@jlcpcb.com but any answer for my question is:

Usually our engineer will check the boards when you upload your file in our website.
They will generate corrected DFM analyse in our website and you can check it .
If there is any components placed wrongly in the DFM analyse ,you can send email to us and we will inform our engineer to rotate it for you .


Regards
up8051 aka JarekC.DIY
 

Offline JLCPCB Official

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Re: JLC PCB Prototype Assembly - Incredibly Cheap
« Reply #155 on: March 16, 2020, 03:16:38 am »
sir, please send your file to rebecca@jlcpcb.com, I will follow up your problem, thank you
 

Online up8051

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Re: JLC PCB Prototype Assembly - Incredibly Cheap
« Reply #156 on: March 16, 2020, 09:48:10 am »
Hi JLCPCB

I sent examples file to support and  I received response that has been  forwarded to technical team.
I am waiting for the solution of the problem.

Regards
up8051
 

Offline STUDER

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Re: JLC PCB Prototype Assembly - Incredibly Cheap
« Reply #157 on: March 16, 2020, 06:07:35 pm »
 :)good
 

Offline essele

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Re: JLC PCB Prototype Assembly - Incredibly Cheap
« Reply #158 on: March 29, 2020, 03:28:45 pm »
Thanks MarkR42 for the comments and code updates.

I've incorporated your changes back into the original tree, along with some more rotation updates.

I've also just placed my first assembly order, so it will be interesting to see how this works out. Not very complicated in terms of variety of device types, but there are quite a lot of line items (22 lines), with about 70 components on each board.

I'll post some photos when they arrive.
 

Offline essele

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Re: JLC PCB Prototype Assembly - Incredibly Cheap
« Reply #159 on: April 06, 2020, 01:28:56 pm »
So my boards have arrived ... I must say I'm very impressed with the speed and support during the process.

The boards were submitted on Monday 30th March, and despite all of the current challenges, they arrived today -- 7 days for assembled boards is very impressive.

For the most part I think things look good ... certainly the placement software seems to work ok, no problems identified so far...

[attach=3]

I have run into a problem while trying to get the first board up and running ... two of the resistors were not properly soldered, one end had lifted and therefore wasn't properly soldered. In some ways this was bad luck as the other 4 boards look ok, but I will do a more thorough inspection.

[attach=2]

I did also have one board that seems to have some etching problems, the tracks have a large number of blobs along the edges, the is only one board and I don't think it will impact anything ... I've never seen anything like this with all prior boards from JLCPBC, and the other four boards are good.

[attach=1]

I'll update if I discover any more issues as I finish populating and testing the boards.
« Last Edit: April 06, 2020, 01:32:15 pm by essele »
 
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Offline SMTech

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Re: JLC PCB Prototype Assembly - Incredibly Cheap
« Reply #160 on: April 06, 2020, 02:45:13 pm »
So my boards have arrived ... I must say I'm very impressed with the speed and support during the process.

I have run into a problem while trying to get the first board up and running ... two of the resistors were not properly soldered, one end had lifted and therefore wasn't properly soldered. In some ways this was bad luck as the other 4 boards look ok, but I will do a more thorough inspection.


This is called "tombstone" the most common contributor to it is uneven heating either caused by crappy reflow or by thermally unbalanced track layout (e.g one end of device basically on a plane and the other connected to a tiny track). However the other thing that can aggravate it is too much solder paste. However nothing on your board looks like its pushing the rules to any great extent so maybe you were just unlucky, normally if everything is setup right its a very uncommon build issue until you get to 0402 or smaller when all the parameters above start mattering a whole lot more.
You may simply have got lucky on your 7days, since the 30th deliveries out of China are somewhat unpredictable, some ship as normal and others get stuck with the courier for days on end and some lucky countries have reduced or no service.
 

Offline MarkR42

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Re: JLC PCB Prototype Assembly - Incredibly Cheap
« Reply #161 on: April 19, 2020, 09:33:30 pm »
So my boards have arrived ... I must say I'm very impressed with the speed and support during the process.

The boards were submitted on Monday 30th March, and despite all of the current challenges, they arrived today -- 7 days for assembled boards is very impressive.

For the most part I think things look good ... certainly the placement software seems to work ok, no problems identified so far...


Great, you could not get them to place U1, U8 or U9 then? I assume those parts weren't in their library?
 

Offline MWP

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Re: JLC PCB Prototype Assembly - Incredibly Cheap
« Reply #162 on: April 20, 2020, 03:57:38 pm »
Not a beginner to PCB design, but a beginner to KiCad and using Jlcpcb (for pcb & assembly).

I have a board design that's circular, and approx 20mm in diameter.
I also have a few other quite small boards I need fabed and assembled.

What's the best way to go about this?
To panelize the designs myself?
Any tips would be appreciated :)
 

Offline OwO

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Re: JLC PCB Prototype Assembly - Incredibly Cheap
« Reply #163 on: April 20, 2020, 04:06:32 pm »
Yes, panelize it yourself but don't put very long slots on the board. You will have to cut the boards apart with a table saw*, but you won't get charged extra for multiple designs.

* There is a technique involving a strip of wet paper towel on the bottom side of the board when cutting that will create a water droplet on the top of the board, wetting the cut surface and keeping dust in the droplet. I might post some details later, but until you can master the technique you have to do it in a dedicated room and avoid breathing when cutting boards.
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Offline ddavidebor

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Re: JLC PCB Prototype Assembly - Incredibly Cheap
« Reply #164 on: April 22, 2020, 07:05:37 pm »
Yes, panelize it yourself but don't put very long slots on the board. You will have to cut the boards apart with a table saw*, but you won't get charged extra for multiple designs.

* There is a technique involving a strip of wet paper towel on the bottom side of the board when cutting that will create a water droplet on the top of the board, wetting the cut surface and keeping dust in the droplet. I might post some details later, but until you can master the technique you have to do it in a dedicated room and avoid breathing when cutting boards.

THAT'S AWFUL ADVICE
PCBs will dull the blade in seconds
Davide Bortolami,
Fermium LTD
 

Online up8051

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Re: JLC PCB Prototype Assembly - Incredibly Cheap
« Reply #165 on: April 22, 2020, 07:51:23 pm »
Not a beginner to PCB design, but a beginner to KiCad and using Jlcpcb (for pcb & assembly).

I have a board design that's circular, and approx 20mm in diameter.
I also have a few other quite small boards I need fabed and assembled.

What's the best way to go about this?
To panelize the designs myself?
Any tips would be appreciated :)

Panelize boards by "mouse bits".
JLCPCB accept this type of panelization.
 
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Online langwadt

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Re: JLC PCB Prototype Assembly - Incredibly Cheap
« Reply #166 on: April 22, 2020, 09:17:54 pm »
Yes, panelize it yourself but don't put very long slots on the board. You will have to cut the boards apart with a table saw*, but you won't get charged extra for multiple designs.

* There is a technique involving a strip of wet paper towel on the bottom side of the board when cutting that will create a water droplet on the top of the board, wetting the cut surface and keeping dust in the droplet. I might post some details later, but until you can master the technique you have to do it in a dedicated room and avoid breathing when cutting boards.

THAT'S AWFUL ADVICE
PCBs will dull the blade in seconds

a diamond tile cutting disc works better, but the teeth on a table saw blade is carbide just like the drill bits used to drill pcbs, so while it isn't something you should use your expensive fine wood working saw blade for, it's not going to self destruct in seconds

 

Offline MWP

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Re: JLC PCB Prototype Assembly - Incredibly Cheap
« Reply #167 on: April 28, 2020, 06:06:19 am »
Panelize boards by "mouse bits".
JLCPCB accept this type of panelization.

Perfect. Thankyou.
 

Offline MWP

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Re: JLC PCB Prototype Assembly - Incredibly Cheap
« Reply #168 on: May 03, 2020, 02:09:18 pm »
If an assembled board isn't full populated, do JLCPCB remove solder paste (or, not apply it) to the pads of un-populated components?
 

Offline OwO

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Re: JLC PCB Prototype Assembly - Incredibly Cheap
« Reply #169 on: May 03, 2020, 02:34:30 pm »
They used to leave solder on all pads, but some time in 2019 it changed to no paste on unpopulated pads.
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Offline thinkfat

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Re: JLC PCB Prototype Assembly - Incredibly Cheap
« Reply #170 on: May 11, 2020, 12:16:30 pm »
I've just recently ordered another PCBA job with them, but I come to the conclusion that their parts catalog is much too limited for me to have them assemble prototypes completely.
Most of the active parts I use are not available, or not listed in the package I need and if they're listed, they're likely out of stock.

So, I've decided to just let them place whatever passive parts are on the PCB and assemble the rest manually. That saves a lot of work already (soldering dozens of resistors and capacitors is boring).
It also costs effectively nothing.
Everybody likes gadgets. Until they try to make them.
 

Offline MarkR42

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Re: JLC PCB Prototype Assembly - Incredibly Cheap
« Reply #171 on: May 11, 2020, 12:53:37 pm »
Happily, JLCPCB had parts which worked for all of the parts on one side of my board.

Kicad screenshot and picture of the finished item attached.

I had jlc assemble one side, two boards per panel, which I panelised myself in the gerbers because my individual boards are very tiny (smaller than jlc's minimum size) and had no space for tooling holes. Those were attached with mouse-bites, and I was able to snap them off easily with no problems, the boards are 1mm thick.

I soldered the radio module to the other side of the board and the finished item is shown in another attachment (with a rule).

Overall, their service was cheap and very good.

What I'm slightly worried about, is if I want to make another batch, the motor driver chip drv8837d is now out of stock ( https://jlcpcb.com/parts/componentSearch?searchTxt=drv8837 ) so I can't order any more of these assembled. Had-soldering this chip is a royal pain in the backside (dfn8, 0.5mm pitch), as I did with earlier prototypes.

I originally used the Atmel attiny3217, JLC didn't have that, but they did have the attiny1617 which is almost identical (less flash memory, still enough) - so I fitted that instead.

I think their service is excellent for short production runs where you want to make  e.g. <100 pieces and another manufacturer would probably charge too much setup fee.
 
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Offline OwO

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Re: JLC PCB Prototype Assembly - Incredibly Cheap
« Reply #172 on: May 11, 2020, 03:29:16 pm »
My designs always contain a LOT of passives, and they are always on opposite sides of the board as the ICs, so I've been using JLC SMT for prototypes for as long as I've heard of it.

This is what my latest board looks like as they arrived from jlc:

bottom:
[attach=1]

top:
[attach=2]

after manual assembly of chips:
[attach=3]
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Offline MR

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Re: JLC PCB Prototype Assembly - Incredibly Cheap
« Reply #173 on: May 12, 2020, 05:39:43 am »
My designs always contain a LOT of passives, and they are always on opposite sides of the board as the ICs, so I've been using JLC SMT for prototypes for as long as I've heard of it.

This is what my latest board looks like as they arrived from jlc:

bottom:
[attach=1]

top:
[attach=2]

after manual assembly of chips:
[attach=3]

Which design application did you use? The memory traces look interesting.
 

Offline OwO

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Re: JLC PCB Prototype Assembly - Incredibly Cheap
« Reply #174 on: May 12, 2020, 08:37:45 am »
gEDA PCB. Kicad should work too. You don't actually need the bus routing and automatic length matching features of more advanced PCB software, and they are actually useless in this case because the Zynq has different internal (BGA substrate) lengths for every pin which you have to account for when laying out the traces. I just extract trace lengths from the PCB using the command report(netlengths) which I then copy into a spreadsheet, and then I adjust the outlier traces until everything is mostly equal.
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