HASL and fine pitch soldering - Page 1
Forum section: electronics / general

author: sdouble
author_rank: Frequent Contributor
timestamp: February 08, 2021, 08:50:37 pm
content: Dear friends,I usually order y PCB with an ENIG finish. This time I would like to go for HASL. I do not try to save a few bucks but JLCPCB still pipes out PCBs during the chinese new year period but they pospone all orders including a non HASL finish.The PCB includes fine pitch components like a few 0201 caps and a LT3094 LDO in DNF12 package.How safe is it to foresee such a combo ?thanks for you tips.

author: SMTech
author_rank: Frequent Contributor
timestamp: February 08, 2021, 09:40:57 pm
content: ENIG is always totally flat, so you know exactly how much material is going into your solder joint and the stencil is nice and level across the whole PCB. HASL can be way more variable with lumps and bumps in it, so you don't have that consistency. In all likelihood you won't encounter any problems but the potential is there. When using a manual stencil setup, I personally find it slightly more of an eye-strain lining up a HASL board than a nice gold one but that could just be me.

author: 48X24X48X
author_rank: Frequent Contributor
timestamp: February 09, 2021, 01:25:11 am
content: Quote from: SMTech on February 08, 2021, 09:40:57 pmTotally agree on lining up the stencil with the PCB is painful with HASL. Everytime I thought of saving some money on the prototype, I just decided not to and always end up with ENIG again for the reasons stated above. With ENIG, you have a better consistency. Unless the components size are large, I would recommend sticking to ENIG.

author: S. Petrukhin
author_rank: Super Contributor
timestamp: February 11, 2021, 07:58:38 am
content: The hills of HASL did not prevent me from soldering 0201.But it is really more difficult to lining up the stencil, you need to add a little light.

author: sdouble
author_rank: Frequent Contributor
timestamp: February 12, 2021, 02:24:55 am
content: big thumb down to JLCPBC. they do claim they keep producing during the CNY period but simply get huge delays. I paid for a 2 day production and the process barely started 3 days after validation of te file.

author: phil from seattle
author_rank: Super Contributor
timestamp: February 12, 2021, 03:05:01 am
content: QuoteNot going to defend them but you really should not expect normal operations during CNY. It could be worse - they could have completely shut down.For what it's worth, I have a completed assembly job that has been sitting at "Waiting for courier pick up" for 2.5 days

author: sdouble
author_rank: Frequent Contributor
timestamp: February 13, 2021, 05:15:16 am
content: They do claim that operate during the CNY period. they do sell pcbs wuth 2 day production as a paid option...Quote from: phil from seattle on February 12, 2021, 03:05:01 am

author: phil from seattle
author_rank: Super Contributor
timestamp: February 13, 2021, 03:59:33 pm
content: Well, they did make my PCBs and assemble the boards during CNY. Unfortunately, they are still on the loading dock waiting for DHL to show up...

author: jmelson
author_rank: Super Contributor
timestamp: February 17, 2021, 02:50:02 am
content: i had a huge bad experience with some kind of gold flash finish many years ago. If the pad didn't solder, then it turned black, you had to lift up the chip lead and scrape the pad down to copper and tin it before soldering the lead. Horrible mess!So, I do lead-free HASL with parts down to 0.5mm lead pitch (TQFP-144). I had some issues in the past, but now that I'm using Loctite GC10 I am having VERY FEW problems with the soldering.Jon

author: SMTech
author_rank: Frequent Contributor
timestamp: February 17, 2021, 08:39:30 am
content: Quote from: jmelson on February 17, 2021, 02:50:02 amIt's called black pad, and a known historic issue that used to accompany ENIG, but the process is now so universal & tuned in its now very rare.

author: sdouble
author_rank: Frequent Contributor
timestamp: February 18, 2021, 08:37:45 pm
content: yep tens of ENIG finihed boards produced and never saw a black padQuote from: SMTech on February 17, 2021, 08:39:30 am

author: jmelson
author_rank: Super Contributor
timestamp: February 19, 2021, 04:48:17 pm
content: Quote from: SMTech on February 17, 2021, 08:39:30 amYup, black pad! It was awful, but not discovered until I tried to put a batch of boards through final test. This was in 2007, but the experience scarred me enough that I never want to go through that again. Anyway, I am having incredibly good results with lead-free HASL and Loctite GC10 solder, so I can't see a reason to change what is working.We have something coming up that may use a leadless 100-pin package, so that may push me toward a more planar finish.Jon