surface finish thickness - Page 1
Forum section: electronics / beginners

author: LaserTazerPhaser
author_rank: Regular Contributor
timestamp: January 13, 2019, 02:27:32 am
content: How thick is this immersion gold thickness for both options?site is allpcb.comIt is unlikely to be 1 or 2 microns thick, its likely referring to some class or standards.

author: ataradov
author_rank: Super Contributor
timestamp: January 13, 2019, 03:28:13 am
content: I think they are literally referring to micro-inches. It seems like a reasonable assumption and IPC standards also use "uin" as a unit of measure for this kind of stuff.

author: wraper
author_rank: Unknown
timestamp: January 13, 2019, 03:44:34 am
content: Quote from: ataradov on January 13, 2019, 03:28:13 amUnlikely, 1 microinch would mean that gold is so thin there is almost none of it. You shouldn't see even a tad of golden color.QuoteCopper thickness is often measured in um.

author: wraper
author_rank: Unknown
timestamp: January 13, 2019, 03:50:27 am
content: Hmmhttp://www.unitechindustriesinc.com/services/enig-4552.htmSeems 1um would be too thick for ENIG. But 1 uin too thin.

author: ataradov
author_rank: Super Contributor
timestamp: January 13, 2019, 04:04:37 am
content: QuoteSo the minimum recommended by the standard is 2.0 µin. It seems reasonable that prototyping service will do bare minimum or less. I'm sure AllPcb will do whatever is requested for real orders.

author: LaserTazerPhaser
author_rank: Regular Contributor
timestamp: January 13, 2019, 04:29:37 am
content: Is 2u" too thin to see?

author: LaserTazerPhaser
author_rank: Regular Contributor
timestamp: January 13, 2019, 05:18:22 am
content: Are there tendencies and even reports of Chinese PCB houses "conserving" on the gold?I mean big PCB houses like ALLPCB, JLCPCB and elecrow.

author: LaserTazerPhaser
author_rank: Regular Contributor
timestamp: January 13, 2019, 05:38:32 am
content: Quote from: blueskull on January 13, 2019, 05:33:20 amIt seems ALLPCB is the most comprehensive and option filled retailer. Unlike other retailers they even permit you to have no silkscreen, determine gold plating thickness and even have no surface finish which is really great for certain boards.

author: LaserTazerPhaser
author_rank: Regular Contributor
timestamp: January 13, 2019, 08:04:53 am
content: Quote from: blueskull on January 13, 2019, 05:50:46 amIt cannot have any soldermask this is not a typicall antenna. But nice of you to detail magnetic issues the nickel layer can cause. I would have made it 2.4mm thick if that didn't demand 2 or more layers.

author: Zero999
author_rank: Super Contributor
timestamp: January 13, 2019, 07:04:55 pm
content: Quote from: blueskull on January 13, 2019, 05:50:46 amWould tarnishing be a problem? I would have thought that as long as there's still enough silver, under the layer of oxide it would still be good or does the oxide have high dielectric losses?

author: KL27x
author_rank: Super Contributor
timestamp: January 15, 2019, 12:57:27 am
content: This thread brings back a bad memory on a collaboration. I did the circuit design and firmware, but due to time constraints, physical quirks, and the sheer quantities involved, my client wanted a more experienced PCB guy. The housing was done by another company.The board was in two parts, with some gold fingers making a contact pressure between the boards. I identified a problem with the prototype because the soldermask on the board encroached on the board with the gold plated contacts. The obvious solution is to enlarge the opening in the soldermask on the bottom board or to reduce the size of the pcb on the top board, so that everything fits without the soldermask getting in between.I don't know what the big deal was, but he insisted to add carbon to the pads to make them thicker. I knew this would cause other issues and I explained it best I can that this was unacceptable. The housing was already done, and it didn't allow for this. I wanted to strangle him through the phone. He finally conceded to not add carbon. He claimed he would thicken the pads with gold plating. So I said sure, but only gold (knowing there's no way he is going to add gold of any thickness to the board out of his own contracted fees).Well, the boards arrived, and they had carbon on the pads. I eventually respun the PCB myself, but not before it cost my client $100,000.

author: langwadt
author_rank: Super Contributor
timestamp: January 15, 2019, 01:26:28 am
content: Quote from: ataradov on January 13, 2019, 04:04:37 amthe IPC i looked at said min. 2uin for default ENIG, but min. 1.58uin can be used for soldering only