Author Topic: JLC PCB Prototype Assembly - Incredibly Cheap  (Read 44534 times)

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Offline MR

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Re: JLC PCB Prototype Assembly - Incredibly Cheap
« Reply #175 on: May 12, 2020, 09:26:09 am »
I just wondered because the length matching is quite creative.
 

Offline uer166

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Re: JLC PCB Prototype Assembly - Incredibly Cheap
« Reply #176 on: May 19, 2020, 05:07:57 am »
Just wanted to show my first experience with this assembler. Got 2 of these babies for $160 shipped, pretty amazing! Every part here (except big inductor) was placed by them. No idea if they work, there's some fiberglass dust from the post-assembly routing, but looks pretty good! Maybe 1/5 of the price from Allpcb and such, but I did have to design using their components..
 

Offline MarkR42

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Re: JLC PCB Prototype Assembly - Incredibly Cheap
« Reply #177 on: May 19, 2020, 08:20:11 am »
That's a lot of caps. But please try it, and let us know the results.

My much smaller, simpler boards (with a lot fewer parts) seem to have a 100% yield so far...
 

Offline uer166

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Re: JLC PCB Prototype Assembly - Incredibly Cheap
« Reply #178 on: May 19, 2020, 06:35:54 pm »
That's a lot of caps.

It's actually not enough, those Lelons don't quite handle the 4A ripple current that well..
 

Offline danie1

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Re: JLC PCB Prototype Assembly - Incredibly Cheap
« Reply #179 on: May 23, 2020, 04:58:02 pm »
I've made a tool to scrape LCSC product info for the parts in the assembly service to make a more usable tool for finding parts if anyone is interested:

https://github.com/cs2dsb/lcsc-scrape.rs

There's a pre-built database in the releases folder so you don't have to run the scraper (takes hours to do all 37k plus they might ban you? who knows).

I made it because I was fed up of libreoffice/google sheets taking minutes to update when attempting to apply a filter. The SQLite database can be queried in < 1 second for complex queries and contains basically all info available from both LCSC and JLC including all parameters listed on the LCSC product page, stock and basic/extended state from JLC and prices from both. It's at least as accurate as the spreadsheet from their SMT assembly page and has a lot of extra info for the majority of parts.

Every field is directly in the database as a string but I've also "post-processed" it to convert prices and voltages to floats so you can do numerical comparisons on them without mucking about with casting in SQL. These fields are prefixed with "pp_". I imagine I'll add more post processing as I use the DB but for my test case of finding a DC-DC with specified in & out voltages it worked great.

If you want to use it as a scraper to get up-to-date info please read the whole readme first - there are various ways to update subsets that doesn't result in you hammering LCSC & JLC with requests for hours. The workflow I'm using is update from the parts spreadsheet to get new parts (a handful of http requests), planning the design mostly to completion and finally updating only the set of products I've picked for my design with the latest JLC stock info. Obviously I'm manually checking the datasheets before the final order since the info on LCSC & JLC isn't always perfect or complete.

There's some example SQL at the bottom of the readme in the above repo including simple queries like finding categories, listing parameters available and filtering by criteria.

Open to feature requests/bug reports.

Let me know if you find it useful!
 
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Offline phil from seattle

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Re: JLC PCB Prototype Assembly - Incredibly Cheap
« Reply #180 on: May 25, 2020, 05:12:25 pm »
Is anyone else having trouble getting through to their part library?  I'm trying to fill out the JLCPCB numbers and price in my BOM and keep getting system errors, timeouts and network busy (no duh...).  If I keep at it I can make a little progress - 4 out of 22 part numbers so far.

I've got their spreadsheet but not sure the part numbers match up. And the prices look like they are in Yuan, not $ though the site quotes dollars (to me, anyway).
 

Offline danie1

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Re: JLC PCB Prototype Assembly - Incredibly Cheap
« Reply #181 on: May 25, 2020, 05:32:19 pm »
Yea it's broken today.

The db I posted directly above contains all the prices in US dollars as of 2 days ago.... so you could use that.

Edit: If you are on windows or mac and can't use the app I posted the database is just sqlite so you can use any sqlite client.
« Last Edit: May 25, 2020, 05:34:00 pm by danie1 »
 

Offline phil from seattle

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Re: JLC PCB Prototype Assembly - Incredibly Cheap
« Reply #182 on: May 25, 2020, 05:42:44 pm »
Thanks, I saw that. Appreciate you putting out the effort. I'm in a windows ghetto for my dev machine. I made a mental note to do what it takes to use your data but it WAS kind of low on the list. Maybe not so much now...
 

Offline danie1

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Re: JLC PCB Prototype Assembly - Incredibly Cheap
« Reply #183 on: May 25, 2020, 06:03:37 pm »
Not affiliated but I used https://sqlitebrowser.org/ on my mac for browsing sqlite DBs.

You can browse the table just a spreadsheet if you like or use the query editor in it to execute scripts similar to what I put in the readme.

You wouldn't have to download the huge cache folder to do that, just the binary + db release.
 

Offline phil from seattle

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Re: JLC PCB Prototype Assembly - Incredibly Cheap
« Reply #184 on: May 26, 2020, 12:35:21 am »
JLCPCB seems back on line.  I actually had some luck just using the downloaded spreadsheet and simple searching and filtering in the open office spreadsheet. I'm probably a week away from putting in an order - need to get my first version of the PCB back and verify first but getting a pretty good sense of what it takes.

One thing that seems clear - I really need to keep a close eye on available components while designing my board.
 

Offline MarkR42

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Re: JLC PCB Prototype Assembly - Incredibly Cheap
« Reply #185 on: May 26, 2020, 07:03:56 am »
Yes, absolutely, I've found that they run out of stock of components often (not the basic stuff) and my design went from out-of-stock of one part, then that part was available, then out-of-stock of another part, then (happily) all the parts became available, so I ordered a batch.

Now I'm looking at possibly ordering another batch and I just hope they stay in stock until I'm ready...

I suspect that the trick may be to use "very common" components and they can stay in stock. But I'm not compliaining as JLC setup fee is very low, and the turnaround time was unbelievable. Will use again.
 

Offline phil from seattle

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Re: JLC PCB Prototype Assembly - Incredibly Cheap
« Reply #186 on: May 26, 2020, 04:08:40 pm »
Yes, 100% agree use the most common parts though it's hard to say what qualifies as "common". Wish they would help with this - maybe keep stats on how many get used in a given period.  As I get more into this, I'm getting a sense of the "best practices" to make JLCPCB work well. 

Another one is to reconfigure your components.  My board has 10 optoisolated inputs and the original design used 2 4-channel ICs and 1 2-channel IC incurring 2 extended charges (no basic optoisolators at all). I first looked at switching to 5 2-channel optos. While reducing to 1 extended charge, it actually increased the price of the components slightly. Though, still a net win.  Then I poked around the database and found a 1-channel opto that was less than 1/4 the cost of the 2-channel one I was using and tons in stock. Specs look right and I may try to order a couple to check out but am pretty sure they will work. The redesign took all of 15 minutes. The net result is a score! more than $1 off the price per board.

[edit] Found a Basic Optoisolator that probably will work! slightly more expensive in quantity 1 but a big break at 100 which when building 10 boards, I get. And no extended part surcharge. Had to tell someone 'cause my wife looks at me like I'm talking Swahili.[/edit]
« Last Edit: May 26, 2020, 08:05:19 pm by phil from seattle »
 
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Offline uer166

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Re: JLC PCB Prototype Assembly - Incredibly Cheap
« Reply #187 on: May 27, 2020, 07:38:13 am »
It works, programs, and the current sense and control loops and protections are good! Software-defined boost DCDC, about 95% efficient at 130W, 30Vin, 120Vout on one of the two phases. The superfast diodes had to go and got replaced with SiC though, reverse recovery created massive ringing..
 
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Offline Marmotta

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Re: JLC PCB Prototype Assembly - Incredibly Cheap
« Reply #188 on: May 28, 2020, 08:43:57 pm »
What has people's experience been with waiting for extended parts to be restocked? I redesigned my first intended order around a far more expensive THS7368 amplifier based on what they had available, thinking that the time saved soldering that single component would be worth the extra cost, but that part is now too low in stock for me to order the 50 boards I'd intended on getting. It is worth crossing my fingers and hoping or should I just use my original design with a far cheaper THS7374 and hand soldered the IC? Their FAQ just seems to suggest checking back regularly.
 

Offline danie1

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Re: JLC PCB Prototype Assembly - Incredibly Cheap
« Reply #189 on: May 28, 2020, 08:59:15 pm »
The max31855 I was waiting for came back in stock after a few weeks.

Support said they didn't plan to order more but they reappeared nonetheless.

I've also seen people post support responses that say they've ordered a reel after the customer asked for them. So who knows.

Maybe email them and ask if they've ordered some/will order some. 50 boards may not be much to them but if the overhead of getting another reel of something they want to stock anyway isn't that high, maybe they'll do it for you?
 

Offline JLCPCB Official

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Re: JLC PCB Prototype Assembly - Incredibly Cheap
« Reply #190 on: May 29, 2020, 06:06:43 am »
Hi, friend. Rebecca here.
We will have new functions to solve this problem. Users can set up a private component warehouse according to their own production plan, and reserve / pre-order components to be stored in the jlc warehouse, which can reduce the cost of use (batch is cheaper) while ensuring that components are available, jlcpcb has ordered hundreds of SMT placement machines to expand production capacity and will remove the 50-piece limit.
feel free to approach me by rebecca@jlcpcb.com
 

Offline nuclearcat

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Re: JLC PCB Prototype Assembly - Incredibly Cheap
« Reply #191 on: May 29, 2020, 06:28:36 am »
Hi, friend. Rebecca here.
We will have new functions to solve this problem. Users can set up a private component warehouse according to their own production plan, and reserve / pre-order components to be stored in the jlc warehouse, which can reduce the cost of use (batch is cheaper) while ensuring that components are available, jlcpcb has ordered hundreds of SMT placement machines to expand production capacity and will remove the 50-piece limit.
feel free to approach me by rebecca@jlcpcb.com
Wow! Thats great news. And 4-layer prices drop...
Well done, at least some good news at these times!
 

Offline JLCPCB Official

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Re: JLC PCB Prototype Assembly - Incredibly Cheap
« Reply #192 on: May 29, 2020, 07:17:11 am »
 I think so. Last week I communicated with our manager, he told me discount and better service should be more and more. We do hope JLCPCB will help the community. Price & service matter much, the logistics as well. From my side, I can deliver you guys’ suggestions to our company, I will be there always.  >:D >:D >:D
 
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Offline danie1

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Re: JLC PCB Prototype Assembly - Incredibly Cheap
« Reply #193 on: May 29, 2020, 01:40:39 pm »
Has anyone else had strange behaviour from the STM preview window in the last week or so? I've tried firefox and chromium in case it's browser specific.

It seems to be rendering rounded pad corners inverted or something - I've attached examples, the pink one is from my local gerbv and the green one is from the JLC preview.

I also can't get the preview to show components when attempting to populate the bottom of the pcb. I've tried flipping the signs of x and y in case there's some oddness with mirroring the bottom layer but that didn't help. I tried taking the same pos file, gerbers and bom and just flipping a single component to the bottom and that still doesn't work. As far as I can tell kicad outputs reasonable pos files in all cases and I'm renaming the columns as per the JLC FAQ (the same rename and pos stuff works on the top side).

I'm sure they'd check the rotation and fix it for me but I'd really rather see the preview myself and make sure my output is correct.
 

Offline OwO

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Re: JLC PCB Prototype Assembly - Incredibly Cheap
« Reply #194 on: May 29, 2020, 02:57:34 pm »
gerbers have the origin set at the bottom left corner, while most EDA software have the origin at top left. The generated xy files may be either. It is also ambiguous where the origin actually is; most EDA software outputs coordinates relative to the edges of the gerber file, while fabs usually expect coordinates relative to the PCB edges. In my experience JLC will handle any offset although the preview only works if the origin is set to the bottom left corner of the gerber.
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Offline essele

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Re: JLC PCB Prototype Assembly - Incredibly Cheap
« Reply #195 on: May 29, 2020, 03:55:40 pm »
There are some challenges with the placement previewer ... I had a problem yesterday with a fairly complex board where it put my components in the wrong place. I've got a set of 60 SOIC-8's and each one has a resistor and cap right next to it. The resistor and cap were in the right layout, but next to the wrong IC??

Obviously my first assumption was that my plugin for creating the placement files was wrong, but after reducing the BOM and placement files to just the first three resistors and caps I still saw the wrong placement, and bizarrely in different places to previously (despite not changing the position information.)  If I removed a load of footprints from the PCB then it all started working.

So I suspect there are limitations with how complex the board can be ... not sure why, some buffer overflow or wrap I would imagine.

I have given them all the details, I hope they can fix it ... I also rely on that preview, I'd feel very uncomfortable ordering a board without seeing it first!
 

Offline danie1

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Re: JLC PCB Prototype Assembly - Incredibly Cheap
« Reply #196 on: May 29, 2020, 04:44:39 pm »
OwO's hint about the origin got me fiddling with that + gerbv locally (converting .pos to drill to get it to render) and I've "solved" it. Kicad has options for what to use as the origin in the plot menu (gerbers + drill) but not in the pos dialog. As far as I can tell the pos dialog always uses the grid origin, which could be ANYTHING given I keep accidental hitting that hotkey!

In the end, it wasn't necessary to update the origin, it seems to work fine with it set to 0,0 (top left) but the pos file needs the X coordinates flipped. I suspect kicad is flipping them once and the JLC preview is flipping them again, or maybe neither is flipping them but the gerbers are being flipped on the preview. Who knows!

essele, I agree that there are some weird flakey things in there that I haven't been able to figure out - the most recent one was if the CPL has less than 4 components in it, it only works if you add "mm" after the X and Y positions but with > 4 components it works fine with no units specified.

Still haven't figured out the weird pad rendering but I can ask about that when ordering I guess. As long as the placement is correct I'm sure it'll be fiiiiine right?
 

Offline thinkfat

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Re: JLC PCB Prototype Assembly - Incredibly Cheap
« Reply #197 on: May 30, 2020, 12:57:51 pm »
OwO's hint about the origin got me fiddling with that + gerbv locally (converting .pos to drill to get it to render) and I've "solved" it. Kicad has options for what to use as the origin in the plot menu (gerbers + drill) but not in the pos dialog. As far as I can tell the pos dialog always uses the grid origin, which could be ANYTHING given I keep accidental hitting that hotkey!

In the end, it wasn't necessary to update the origin, it seems to work fine with it set to 0,0 (top left) but the pos file needs the X coordinates flipped. I suspect kicad is flipping them once and the JLC preview is flipping them again, or maybe neither is flipping them but the gerbers are being flipped on the preview. Who knows!

essele, I agree that there are some weird flakey things in there that I haven't been able to figure out - the most recent one was if the CPL has less than 4 components in it, it only works if you add "mm" after the X and Y positions but with > 4 components it works fine with no units specified.

Still haven't figured out the weird pad rendering but I can ask about that when ordering I guess. As long as the placement is correct I'm sure it'll be fiiiiine right?

I never had to manipulate any files to get the placement positions to work. I'm using "JLCKicadTools" and it just does all the magic for me. I've ordered 3 PCBA jobs now and they all worked out fine.
Everybody likes gadgets. Until they try to make them.
 

Offline MarkR42

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Re: JLC PCB Prototype Assembly - Incredibly Cheap
« Reply #198 on: May 30, 2020, 01:50:22 pm »
Has anyone else had strange behaviour from the STM preview window in the last week or so? I've tried firefox and chromium in case it's browser specific.

It seems to be rendering rounded pad corners inverted or something - I've attached examples, the pink one is from my local gerbv and the green one is from the JLC preview.

Yes, JLCPCB does that every time for me with Gerbers from Kicad nightly. This does not appear to affect the final product though. The corners aren't inverted in the actual gerber files, it's just a bug in the previewer.

It's not just assembly, it does it on the pcb gerber preview too.

UPDATE: To be clear, I wrote in the comments section when ordering, and the JLCPCB technician wrote back to me very quickly with screenshots of the (correct) copper layers in his own tools.
« Last Edit: May 30, 2020, 01:52:16 pm by MarkR42 »
 

Offline essele

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Re: JLC PCB Prototype Assembly - Incredibly Cheap
« Reply #199 on: June 03, 2020, 12:55:08 pm »
Just managed to get this board powered up and working...

[attachimg=1]

It's a PoE GPIB board ... really nicely done by JLCPCBA, everything was them apart from the RJ45 port, the GPIB port, the PSoC MCU (not on their parts list), the 10 pin programming port, and the PoE module.

So it basically only took 15 minutes of work from opening the box to having it up and running (well, powered at least ... software still to do!) ... I do love this service -- 2 assembled boards for $30!

I've also just ordered my first 4-layer board with them for assembly ... and it did suffer an alignment problem as I mentioned earlier, definitely their system and not my position file. However they did fully correct it "manually" and the DFM report showed everything in the right place. I'm still worried about this as that's fine with general positioning problems, but rotation may be more of a problem.
 
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