Beginner Home Assembly Journey Episode 1B: Reflow Updates - Page 1
Forum section: electronics / general

author: meshtron
author_rank: Regular Contributor
timestamp: October 09, 2023, 09:05:18 pm
content: I took all the good advice offered inmy previous postand took another swing at reflowing a board myself this weekend. Unfortunately due to unforeseen time commitments, I only had about 4 hours Sunday to spend on it - probably about half what I needed.Things I did:- Leveled and bound my work tables into one relatively flat, level, contiguous platform (mostly in prep for a PnP, but needed to be done)- Over-engineered and 3D-printed a very basic stencil printer bed- Cut down my WAY oversized (380mmX250mm for a 46x64mm single board) stainless stencil to work with the new green machine- Kneaded my (room temperature) GC-10 on a glass plate before use (saw the consistency become homogenous and even worked a few air bubbles out of the mix)- Made a semi-janky but functional stainless mesh standoff for my T-937M reflow so boards wouldn't sit directly on the tray- Pasted a board (three times!) until I got a decent looking paste- Added some random 0603 passives to that board, and reflowed it using Profile 4 on my T-937MThings I wanted to get done but didn't:- Create a custom reflow profile for my little oven - couldn't get the software to install, gave up the fight as it was consuming time I didn't have (I have since gotten a working T937.exe and I think I can get it going now)- Test multiple reflow profiles to see if one worked better than others- Assemble and flow a whole board, particularly with the thermally tough (and most expensive) chip in place- Make a better stencil-holder hinge with aluminum tape that I know I have, but couldn't locate- Also, I did not have a magnifying glass and couldn't get the stencil under my microscope, you can see in the pics it was still a touch offThis looks MUCH better than the first (fully assembled) board I ran through my oven (twice). But, it still looks a bit off to me. The solder joints look a bit "crusty" and you can see in a couple spots there a spot of brown stuff (presumably flux?) left on the finished joint. It almost looks to me like it didn't quite reflow all the way, but I'm not positive that's the case. Maybe the soak time was too long and the flux activated too soon in the process? I'm not sure. Now that I can get the software going, I am going to make what I think is a very close profile to the one described in the GC10 literature and repeat this process, hopefully with slightly better alignment of the solder paste.Also, the pads for the DRV8144 (not populated pic 10) almost look to me like they don't have enough solder. Maybe just because I didn't populate it and, presumably, doing so would've thinned out the solder vs what I got flowing it bare?Anyway - some progress made. More to learn, hoping I can get some time this week to fiddle with software and be ready to full-court-press on getting a whole board assembled and flowed next weekend!EDIT1: Added link to previous post

author: jpanhalt
author_rank: Super Contributor
timestamp: October 09, 2023, 09:28:05 pm
content: I did none of those things in prep for my first reflow. Oven is a T962 (updated). Paste: Kester. Stencil: OshStencil Location: nowhere near level. A few trial runs to calibrate the TC's, then a for real run. It worked far better than I had hoped (64 pin-TQFP MCU and some other smaller, 0.5 mm chips) .1) Use good solder paste2) Use a reflow oven or something else you can trust3) Use a SS stencil4) When placing parts, be organized and use a desk that is a little higher than an average dinner table to chair distance. Having your arms elevated helps when doing placement.

author: asmi
author_rank: Super Contributor
timestamp: October 09, 2023, 09:45:04 pm
content: Quote from: meshtron on October 09, 2023, 09:05:18 pmThat looks normal to me. Attached is a photo of my board right from the oven, as you can see it looks very similar. I typically wash my boards in an ultrasonic washer, and all that stuff washes away rather easily.

author: meshtron
author_rank: Regular Contributor
timestamp: October 09, 2023, 09:58:29 pm
content: Quote from: jpanhalt on October 09, 2023, 09:28:05 pm1) By all accounts GC-10 is good solder paste2) I am using a T-937M Reflow oven3) I am using a SS stencil as shown in the pics4) Assembly is the easy part - the hard(er) part so far has been getting good reflow, especially on a chip that is sitting on top of 3 big 2-sided pours with via stitchingBut, maybe I'm closer than I thought.

author: jpanhalt
author_rank: Super Contributor
timestamp: October 09, 2023, 11:37:16 pm
content: The obvious things seem OK, but are you sure of the temperature profile? Did you calibrate the oven with a standard TC or thermometer?This is my first board. It had a full ground plane on bottom and ground pour on top. Board is about 2" x 3-3/4". Photo is fuzzy due to handheld old Canon camera. (After careful placement, I accidentally bumped the board as I was picking it up to put into the oven. Some parts moved slightly. Carelessness.)My T962 required considerable adjustment of the TC amplifiers to get the actual profile pretty close to the desired profile. I also did a blank profile just before doing my board to warm things up a bit. Ambient was about 66°F. In brief, I would focus on the temperatures and profile.

author: meshtron
author_rank: Regular Contributor
timestamp: October 10, 2023, 12:11:32 am
content: Quote from: jpanhalt on October 09, 2023, 11:37:16 pmYour board looks great! I did not calibrate my oven, probably need to add that to the list of things to do. My first attempt was rough, this one is closer.

author: meshtron
author_rank: Regular Contributor
timestamp: October 12, 2023, 03:05:13 pm
content: As another update (unfortunately without pictures)...I got a decent magnifying glass in last night which I've been waiting on to be able to better confirm my stencil placement. With that, some paste kneading to get air out and up to room temp, I got what I would consider a perfect paste laid down. One lay-down pass, one clean pass, dead center on every pad - looked fantastic.I ran it through my reflow oven using the same profile as last time (though I now finally got my PC to talk to the oven so can make my own profiles if needed), and it came out looking amazing! Joints were shiny and pretty, fillets all looked nice, and on the tough chip (half large pads, half QFN type pads, big solder pours) it looked great AND no shorts detected. VICTORY!!So, I soldered on all the through-hole parts and powered it up. Immediately noticed no "power" LED came on, so I shut it back off (was on for ~1 second). Felt the LM7805 seemed warm. Put my finger there, flipped it on again and immediately that started getting hot. Did some probing, and somehow I have a short between 5V and GND!It was late, I didn't have tons of time to troubleshoot, but I confirmed every component was the right part in the right position and obviously my schematic doesn't have a short. I think I've got a short under the MCU which is QFN28. I have a couple other random pins that are testing as shorted to GND too, so that seems the logical spot. I tried adding flux and touching the pins last night, but they look okay and didn't change much. I think my next step is to just desolder the MCU, pull it off and have a look. That will also let me test if the short goes away. Going to be tricky to get to the MCU now that I've added all the tall parts (which surround it), but should be doable.IF it turns out that's the issue, I need to figure out what changes to make so that I can reliably reflow QFN parts OR I need to redesign my board for a different MCU that's a bit less fiddly.

author: jpanhalt
author_rank: Super Contributor
timestamp: October 12, 2023, 03:14:27 pm
content: That's good news. At least the reflow part went well.The short is another issue. As you clearly realize, a short anywhere will look like a short, period, and it will be hard to find where it happened. I have not done a QFN by reflow. The only leadless packages I have done were small and had exposed contacts on the sides. I hand soldered them.Edit: I would make my best guess, remove the chip and see if that was the problem. Does the MCU have exposed contacts? If so, it might be hand solderable. I might start with another chip that can be hand soldered. As a final resort. I believe a QFN can be soldered by hot air.Regards, John

author: meshtron
author_rank: Regular Contributor
timestamp: October 12, 2023, 04:04:12 pm
content: Quote from: jpanhalt on October 12, 2023, 03:14:27 pmYeah thanks - I was very happy the reflow part went well, and yeah tracking down the short seems like a pain. Would've been less so before I added the through-hole parts!This QFN28 (ATTiny48) doesn't appear to have side-pins other than a tiny "nub" at the bottom. I noticed after the first reflow the solder didn't really wick up the sides. But, some flux and hot-air got it to where I did get it to flow a bit better, no improvement though on the short.If I pull the MCU and the short doesn't go away, I guess I still learn something!

author: asmi
author_rank: Super Contributor
timestamp: October 12, 2023, 08:02:58 pm
content: How do you guys manage to get shorts underneath QFNs? There is no space for that if the footprint is done right, unless you put a ridiculous amount of solder paste on the bottom pad and the whole part is floating on top of solder. I've soldered and reflowed over a thousand of QFNs and QFN-like parts of all sizes and shapes, and not a single time did I get any short underneath - only shorts between pads which were easily fixed with a soldering iron and flux, and even that has been a while ago. Can you show your footprint and paste layer for this QFN, as well as a full part number so that I can see what manufacturer recommends for it? I have a suspicion that your paste openings are way too large.Also I thought that was kind of obvious, but I always check all power rails for shorts right after reflow, before you solder in any through-hole parts, and then once again check them again right before I power up the board for the first time. And visually inspect the PCB after reflow under a microscope for soldering defects - again, before soldering any further parts, so that you can fix defects before larger parts will get in the way.

author: meshtron
author_rank: Regular Contributor
timestamp: October 12, 2023, 08:45:01 pm
content: Quote from: asmi on October 12, 2023, 08:02:58 pmI'm new at this - but apparently it's a special talent I posses as I did it on my first try.Quote from: asmiI sort of did, but (clearly) not enough. I did visually inspect everything as far as I could tell (I'm definitely understanding how worthless my cheapo digital microscope is now), all the solder joints looked great. Clean, zero bridging, everything nicely lined up (telling me it had flowed and self-centered well). And I did check for shorts between Vbatt and Vout (where I had a problem last time), that being clean thought I was good! I didn't check that +5V and GND weren't connected, definitely will do that on the next one (probably tonight).I ordered the stencil with the boards from JLCPCB - I gave no input on aperture sizing. The part in question is anATTiny48 in QFN28(which they call 28M1). I was able to get a DXF of the stencil (though there appear to be some things that don't match reality - like the rounded exterior corners in the DXF but square corners on the real stencil). I will get an overlay of that on the board here in a few and share.Most of the pins on one side of the MCU tone out as shorted to ground, but I cannot see any bridging or anything that looks different on that side vs the other 3 sides which seem normal. I've flux'd/ironed/hot aired multiple times, but not sure I'm making any difference there. I do think my next step is probably pull the MCU, but I'm not sure I'm up for trying to put it back if I see the problem (or not) - feels easier just to try again with a fresh board.

author: meshtron
author_rank: Regular Contributor
timestamp: October 12, 2023, 09:18:28 pm
content: So - I found what appears to be a "digital zoom" on my terrible microscope, but this is the best picture I can get of the pins that are shorted.All the pins labeled on this pic (and only them, other 3 sides are okay) are shorted to GND. AVCC is connected to +5V, so that's probably my problem there. I have re-re-re-re-touched these and I can make them look slightly different, but not better than this. I can't tell if there is actually a pool of solder underneath the chip that is peeking out at the edges or if that's just reflections from flux.EDIT TO ADD: Makes me wonder if I originally DID have some bridging or shorting under the chip and that damaged the MCU internally. I dunno - either way I think I need to pull it and see if the short disappears with it.EDIT2: First pic had pins mislabeled. GND is the center pin, it's that pin plus the 3 adjacent that are shorted together.

author: asmi
author_rank: Super Contributor
timestamp: October 12, 2023, 09:28:55 pm
content: That looks about right to me. Can you please post photos of the footprint from clean pcb, as well as photo of openings in the stencil for it?

author: asmi
author_rank: Super Contributor
timestamp: October 12, 2023, 09:36:32 pm
content: BTW, if you would like a recommendation for a good digital microscope for inspections, search for "LM249MS" on Amazon. It's relatively affordable and has very long focal length, so you can even solder under it, but of course lack of depth perception will make it harder, for soldering I highly recommend a stereo microscope.

author: meshtron
author_rank: Regular Contributor
timestamp: October 12, 2023, 10:55:27 pm
content: All right - got the stencil vs board pic (at least in the world according to CAD, but presumably these are pretty close).I can't tell if it looks okay or not. Maybe a bit too much void area on the pins, but the center pad has a fair bit of void area so maybe okay?By my calcs, stencil exposes 38% of the center pad - that seems to match with what I've seen/heard recommended. Maybe longer (towards the outside) pin pads would improve my situation.Will be done working soon and can go desolder and see what's under the IC.EDIT: As a sanity check, I pulled out the first (badly failed) board I reflowed, and in addition to the short between Vbatt and Vout, it's also shorted nearly everywhere to GND. Most of that seems to trace back to the MCU also.

author: meshtron
author_rank: Regular Contributor
timestamp: October 12, 2023, 11:07:18 pm
content: Quote from: asmi on October 12, 2023, 09:36:32 pmThank you, that's definitely what I should have bought the first time around. Even has a $40 coupon right now so it's $149!! I have two 4k, HDMI-output scopes on the way right now, should arrive in a week or two. I have a couple monitors set up in my work space now, one of which is also 4k. I'm hoping that once I find the right stands for those scopes, I get much improved workability (with working height) and picture quality, plus the option to put the screen right where I want it.

author: meshtron
author_rank: Regular Contributor
timestamp: October 13, 2023, 12:42:58 am
content: I keep spamming my own post...Anyway, here are some actual photos of the MCU pad and the DRV8144 pad on a clean board. Similar sizes, but the MCU pad has some weird looking solder mask right in the area I'm struggling with. Is this normal? I don't see the darker green solder mask anywhere else on the board.EDIT: Pitch on the MCU is 0.45mm, pitch on the DRV8144 is 0.5mm so not quite the same, but very close. Weird to me how different the masks/pads look.

author: asmi
author_rank: Super Contributor
timestamp: October 13, 2023, 02:25:06 am
content: It looks like your solder mask expansion is too high, so you've got breaks in the solder mask - this is where shorts are coming from. See a couple of examples for QFN-like parts in attachment - this is what correct footprints should look like.Also I see you're using HASL - that explains where excess solder is coming from (because your pads already had solder before you added any solder paste). I only ever use ENIG finish, it's totally worth the premium.

author: meshtron
author_rank: Regular Contributor
timestamp: October 13, 2023, 02:51:37 am
content: Quote from: asmi on October 13, 2023, 02:25:06 amYou know - as I've been going down this path, I keep seeing people saying, offhandedly, "just use some bad or extra boards you have laying around to do XYZ..." And I think to myself "why would you have a bunch of bad boards around?"Until your post I had never heard of "solder mask expansion" nor ever considered HASL vs ENIG, etc. Now I've researched both those things, I think you're spot on. It seems like it should be possible to get this to work as-is, but clearly it's a bit beyond my skills.So, I'll make a couple other tweaks (removing my poorly-conceived low-side reverse-polarity protection diode for one) and order some new boards with tighter solder mask expansion on that spot and HASL finish.Honestly, I am loving this sh**. So many details, so much to learn, so many potholes for me to step in. Some day I'll look back and say "man, those people really were right that doing it myself was a terrible idea!"Sincere thanks for the insights and input. Next step underway!!

author: asmi
author_rank: Super Contributor
timestamp: October 13, 2023, 03:07:31 am
content: Quote from: meshtron on October 13, 2023, 02:51:37 amLOL Every PCB designer has his/her very own "Box of shame" full of botched PCBs for a reason, and don't think even for a second that you will avoid this fateIt has been proven many times that making mistakes is the best way to learn. Successes don't teach nearly as much as failures do.Quote from: meshtron on October 13, 2023, 02:51:37 amI would just solder them manually using a hot air gun. If you can use leaded solder (for example, these boards are for your own needs), it will be even easier. Tin pads a bit, add flux and apply some heat. It may seem hard at first, but eventually you will get a hand of this, and soldering a QFN will take no more than a minute.Quote from: meshtron on October 13, 2023, 02:51:37 amNowadays you can simply zero-out your expansion and let PCB fab deal with it (they typically add a bit of expansion by themselves as required for their process tolerance). I typically set it to 0.05 mm, except for some super-small parts which command even smaller expansion.Quote from: meshtron on October 13, 2023, 02:51:37 amIt's not a terrible idea at all if you enjoy learning. It does have many bumps along the road, but like I said above - making mistakes is the best way to learn.Quote from: meshtron on October 13, 2023, 02:51:37 amYou are more than welcome. Good luck with your endeavors!

author: meshtron
author_rank: Regular Contributor
timestamp: October 14, 2023, 05:19:47 pm
content: All right - removed the MCU this morning and sure enough, the 4 pins in question are very much bridged UNDER the TQFN chip. For grins, I tried reheating and when the solder re-melted, it did not pull away (at all) from those bridges. Everywhere else re-flowed back onto its pad. So, I hit it with an iron and some wick (without any pulling or mechanical stress), and I think what I've got now is basically bare FR-4 between the pads.So, going to stencil a couple of new boards without the MCU pads, reflow them, then try to hand-solder the MCU in place and see if I can get at least one board that is fully working so I can test it out.

author: jmelson
author_rank: Super Contributor
timestamp: October 14, 2023, 05:59:12 pm
content: Yup, WAAAY too much solder there. Remember, the chip sucks down by surface tension, and all the solder is squeezed sideways as that happens. The solder has to be VERY minimal to prevent the excess from squeezing sideways. It is a delicate balance, and there is no way to inspect except X-ray.Jon

author: jpanhalt
author_rank: Super Contributor
timestamp: October 14, 2023, 06:39:03 pm
content: I second ENIG for your next board. Also, there is little reason you cannot extend the pads just a little outside the outline of the chip to make hand soldering, if necessary, easier.

author: meshtron
author_rank: Regular Contributor
timestamp: October 14, 2023, 07:10:12 pm
content: Yep, ENIG on next one and I will see of I can tighten up the mask expansion some. I also think I probably lit up this short like an incandescent bulb when I plugged it in which caused more damage to the board (and maybe the chip).I like the extended pad idea too, no downside and would give me a bigger window to get things right.I am going to try to stencil and reflow another one or two today but going to remove some solder from the pads before assembly and tweak the reflow profile a bit first.If I can't make that work I will leave the MCU off for reflow and hand solder a couple. All good lessons and experience!

author: asmi
author_rank: Super Contributor
timestamp: October 14, 2023, 07:57:21 pm
content: Quote from: meshtron on October 14, 2023, 07:10:12 pmSince you shorted power to ground, I don't think chip was damaged as all current bypassed it via the short.Quote from: meshtron on October 14, 2023, 07:10:12 pmMany vendors publish 3D step models of their parts - use them to your advantage! I use Altium, it contains IPC footprint generator, but after creating it I always try moving pins outside a bit while using 3D model to ensure all pins still have full contact with pads. If you are not pressed for space, "pulling" outside pads a bit away from the bottom pad (even 0.05 mm might help!) will make things easier for both you and your PCB fabricator - because it makes solder mask slivers wider and so there is less chance of them breaking off.

author: meshtron
author_rank: Regular Contributor
timestamp: October 15, 2023, 12:49:02 am
content: Some success today! I decided to bite the bullet and figure out the software for the T-937 and generate a reflow profile that better matched the GC-10 engineering sheet.With no other changes to paste, stencil, etc. I built another one and put it in the oven. And, it worked! I carefully checked everything before adding any through-hole parts and couldn't find anything amiss. So, I soldered on the terminals, switched it on and my green power LED lit right up!Didn't have time to try to program it before evening commitments, but I expect it will take a flash just fine early tomorrow.Doesn't negate the changes I need to make next round, but good possibility I can utilize some or even most of these boards for testing which is great.Thanks again to everyone who's provided input - you were all spot on!EDIT: Took a flash with no problem!!! More testing to do, but feels very close to first FULLY working board.EDIT2: Wow, phone spelling not optimal.

author: HwAoRrDk
author_rank: Super Contributor
timestamp: October 15, 2023, 04:57:08 pm
content: Quote from: meshtron on October 12, 2023, 08:45:01 pmIf the stencil doesn't exactly match your design files in terms of details like rounded corners, then I suspect JLCPCB may have ignored your paste layer file and created the stencil from the solder mask layer (i.e. the pad shapes). I've heard they often do this, even when specifically provided with a stencil file.

author: meshtron
author_rank: Regular Contributor
timestamp: October 16, 2023, 06:31:37 pm
content: Quote from: HwAoRrDk on October 15, 2023, 04:57:08 pmThanks for posting this! My first thought was "I didn't even make a stencil profile, so almost certainly on me." But, I did a little digging. And, sure enough, Fusion 360 (Eagle) by default creates a paste layer awkwardly called "tCream" (I don't have any bottom components). So, I looked at my tCream layer and you are spot on - JLCPCB ignored it and did their own. It appears that some of what they did was good (my tCream shows almost the whole center pad under the TQFN as pasted, JLCPCB broke it up into 4 smaller windows with ~40% coverage), but some was bad (they increased the amount of paste area on the pin pads for the same TQFN part which has way too much solder on it).But, another good thing for me to be aware A) that I'm generating (intentionally or not) and B) could be used or ignored by a fab.Going forward, once I get done with crawling and start contemplating trying to stand up and walk on my own, seems like customizing my paste expectations AND explicitly directing shops to adhere to my design is a pretty important tool to have in my toolbox!

author: asmi
author_rank: Super Contributor
timestamp: October 16, 2023, 06:37:50 pm
content: Quote from: HwAoRrDk on October 15, 2023, 04:57:08 pmThis never happened to me. And the reason I know this is because they often asked me questions about some features of a paste layer not lining up with soldermark layer (this often happens for DC-DC converters as they tend to have weird footprints with several exposed pads underneath, and so you need to have smaller paste apertures to reduce amount of solder paste). I always tell them to manufacture as per paste layer, and so they do.

author: jpanhalt
author_rank: Super Contributor
timestamp: October 16, 2023, 07:13:54 pm
content: Re: "cream"Autodesk bought EAGLE, then decided to roll its own. The solder paste layer in EAGLE is called "cream." Just FYI. I like history, and have been using EAGLE since version 3.

author: meshtron
author_rank: Regular Contributor
timestamp: October 16, 2023, 07:56:54 pm
content: Quote from: jpanhalt on October 16, 2023, 07:13:54 pmI'd never heard it called "solder cream" but a search for that does indeed pull up some results.Also, I'm not sure how much EAGLE is left in the Fusion 360 implementation, but I've been pretty impressed with it so far. Definitely a learning curve moving from "theoretical" library parts to actual models that I can buy and use, but I think I've got that organized now too. I bought my first license of Autodesk Inventor in 2008 (back when one could buy a perpetual) and have been using it since then, so the 3D CAD part of Fusion feels a bit cartoonish to me. But, so far it's been capable of doing everything I've asked it to other than not install on the C drive

author: asmi
author_rank: Super Contributor
timestamp: October 16, 2023, 08:40:50 pm
content: One more thing I always do is review generated Gerbers in external program just to make sure - even though Altium does have a Gerber viewer, I prefer using external program for the "second opinion" so to speak. I use a free edition of ViewMate by Pentalogix, it's UI is a bit weird, but it does the job. I mostly check non-standard footprints for potential issues with mask layers (soldermask, paste layer), end ensure all drills and routes are where they are supposed to be, over time you will learn what PCB features to pay attention to. And don't ever rush to order PCBs! I have a rule of "one day hold-over" - meaning that I never place order on the day I made any changes to PCB, to allow me to review everything next day with a fresh head. This saved quite a bit of money for respins due to stupid mistakes.

author: jpanhalt
author_rank: Super Contributor
timestamp: October 16, 2023, 10:44:36 pm
content: Here's what I use:https://www.easylogix.de/products_detail.php?prog_id=1There are several.Despite the .de, the English version works fine.

author: asmi
author_rank: Super Contributor
timestamp: October 16, 2023, 11:55:12 pm
content: Quote from: jpanhalt on October 16, 2023, 10:44:36 pm249 euro? No, thank you. I'd rather use what I use right now for free.

author: jpanhalt
author_rank: Super Contributor
timestamp: October 17, 2023, 09:50:37 am
content: I use a free version, but haven't used it in over a year. All I have to do is enter a username and password. I was still able to sign on this morning.

author: asmi
author_rank: Super Contributor
timestamp: October 17, 2023, 12:51:08 pm
content: Quote from: jpanhalt on October 17, 2023, 09:50:37 amIt's only free for non-commercial use. Oh, and that whole "sign-in" thing is a no-go - software which phones home is forbidden on my PC and their authors go to the hell.

author: Matt-Brown
author_rank: Regular Contributor
timestamp: October 17, 2023, 02:15:55 pm
content: Not sure if accident or design, but you have non soldermask defined pads.It may also be too tight a space for some boards houses to do quick turn and keep registration, so they remove the mask.For NSMD pads you need an ap reduction on the stencil. that way it will gasket on the pds and not slump as much into the areas where there is no mask and cause the shorting

author: sithebionic
author_rank: Newbie
timestamp: October 17, 2023, 04:33:29 pm
content: HiYou should consider Eurocircuits CPL Editor.On their website you upload your gerbers, bom and cpl file (pick and place file) and they have a neat option where you can see your PCB (your gebers) and they place above their footprint (independent on yours). It is really neat to avoid losing your time on a bad footprint. AND you can download their footprints too for their components if you like. I think they have eagle footprint files too.You can watch it here, this guy and Rick Hartley have teached me much.R.

author: asmi
author_rank: Super Contributor
timestamp: October 17, 2023, 05:54:06 pm
content: Quote from: sithebionic on October 17, 2023, 04:33:29 pmNo, thanks, I'm not uploading my gerbers to random websites.

author: meshtron
author_rank: Regular Contributor
timestamp: October 17, 2023, 06:26:11 pm
content: Again - really appreciate all the input. I think I have a way to check Gerbers offline, and it makes sense to me that outputting from one system and reviewing in another is a more robust way to spot differences.Out of curiosity and planning to try to run 4 or 5 more boards this weekend, I checked a few more of my boards from JLCPCB. The green one in this pic is a bit of a yucky one I found (only the 3rd I checked). The blue one is the prior version (different layout, same chip) I had made at PCBWAY. These both would have been made with identical footprint/solder mask/specifications as I did not touch this footprint between revisions.Looks to me like the PCBWAY version is just cleaner and more consistent AND it's got solder mask where the PCBWAY version doesn't. So, next round - in addition to all the other changes - I'll be going back to PCBWAY to give myself the best chance of decent yield as I assemble and reflow more of these boards. So, even though I've wasted ~$50 on parts on a couple bad boards, tripping over this issue now has taught me lots of important considerations that will hopefully give me a wider window of successful assembly going forward!GREEN = JLCPCBBLUE = PCBWAY