Talk:Printed circuit board/Archive 2

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Archive 1

Archive 2

Multilayer board?

Not one mention. How about a paragraph. — Preceding unsigned comment added by 69.151.60.126 (talk • contribs) 08:26, 12 June 2011

X-ray picture

I have removed this image from the article. It is a nice picture, but I don't quite see the relevance that it has to the article text (it was inserted into the test section). If it does have relevance, we need some text to go with it to explain. SpinningSpark 12:20, 5 April 2010 (UTC)

I can get some x-rays of maybe a 4-layer PWB's with out components, so it will not be cluttered. This image has the components installed. Very confusing. What I can do maybe is an image of the top of of the board and then an x-ray of the same area showing all the stuff inside you don't see. I'll put it on my list. -- :- ) Don 05:38, 14 October 2012 (UTC)

Electroplating

Didn't want to risk changing this erroneously so I'll post a comment to see if anyone else can confirm.

PCB copper electroplating machine for adding copper to the in-process PCB
PCB's in process of adding copper via electroplating

The PCB substrate in these images appears to already have copper on them and a coating of what appears to be already developed photoresist - if this is the case then these boards cannot still be in the process of electroplating nor are they likely to still be in the machine designed to do so - more likely some sort of drying rack ready to be etched. Tim Bell87 (talk) 02:11, 3 June 2010 (UTC)

Just stumbled upon this article. They are doing what is called pattern plating. The laminate with copper on both side already, is drilled, then imaged with photo resist, and then plated. This is usually used for heavy copper plating or fine line technology. They may start with 1/2 ounce copper laminate, then plate 0.001-0.002" of copper in the open image area. After copper then tin-lead or some other protective metal is plated over the copper and the blue photo resist stripped. When it goes to etch, there is only the original 1/2 ouch of copper that needs to be removed. -- :- ) Don 21:15, 8 August 2012 (UTC)

Wired Chassis

I've seen the term wired chassis and wired chassis assembly used as an alternative "technology" relative to printed circuit boards. I'm not an expert; should this be clarified in this article? If not, would a knowledgeable person please find a good redirect link for these terms? —Preceding unsigned comment added by 192.31.106.35 (talk • contribs)

This is point-to-point construction (or a version of it) already mentioned in the article. SpinningSpark 01:21, 5 June 2010 (UTC)

Error

The sentence, "In 1949, Moe Abramson and Stanislaus F. Danko of the United States Army Signal Corps developed the Auto-Sembly process in which component leads were inserted into a copper foil interconnection pattern and dip soldered." is in error. The original designer of this process was Samuel J. Lanzalotti, an electrical engineer and inventor, who, with the two aforementioned electrical engineers, worked at Fort Monmouth, New Jersey. The prototype Lanzalotti designed shows the three layers within the circuit board and displays side-by-side two different methods of etching that could be used. With Lanzalotti's design notes in hand, the two others applied for the patent and received a $10,000 award from the government. This information was never disclosed to the public.--96.242.73.244 (talk) 11:12, 4 September 2010 (UTC)

If the information was never disclosed then it is not possible to verify and thus cannot be included in the article. See: The threshold for inclusion in Wikipedia is verifiability, not truth HumphreyW (talk) 11:26, 4 September 2010 (UTC)

The existence of

SF Danko and SJ Lanzalotti, "Auto-Sembly of subminiature military equipment," Electronics, vol.27, pp.94-98; July, 1951

would seem to suggest that Lanzalotti did indeed have a lot to do with this, but I don't have access to a copy. Danko, in his publications, would also appear to be citing Lanzalotti if this search of Scholar is anything to go by. SpinningSpark 13:24, 4 September 2010 (UTC)

CEM-3 and FR-4

Article states "Well known prepreg materials used in the PCB industry are ... FR-4 (Woven glass and epoxy), ..., CEM-3 (Woven glass and epoxy) ..."

I read elsewhere that CEM-3 is not woven, which is its main difference from FR-4. Sorry that I do not have an authoritative reference on this. — Preceding unsigned comment added by Zlel (talk • contribs) 04:42, 14 December 2010 (UTC)

Composite Epoxy Materials (CEM) are a group of composite materials typically made of woven glass fabric surfaces and non-woven glass core combined with epoxy resin. The core is non-woven fabric! That's the difference between CEM material and FR-4 material.--203.163.97.36 (talk) 05:19, 29 June 2012 (UTC)

general electronics assembly

Is there a more general article that compares and contrasts the many ways of electrically connecting and mechanically supporting electronics components? Or a general category to simply list these techniques? solderless breadboard, point-to-point construction, wire wrap, Project Tinkertoy, general-purpose printed circuit board: prototyping stripboard and prototyping perfboard, custom printed circuit board, etc. --68.0.124.33 (talk) 03:26, 26 October 2010 (UTC)

General comments

this article is full of fundamental errors, e.g.:

drilling is performed before etching, but the sequence of sections suggests otherwise

section "Exposed conductor plating and coating" sentence "PCBs[2] are plated with solder, tin, or gold over nickel as a resist for etching away the unneeded underlying copper.[3]" is nonsense

212.159.59.5 (talk) 14:09, 15 February 2011 (UTC)

BGA by hand

Article states that it is impossible to solder BGA by hand. This is not true. It is possible to remove, reball and replace BGA and uBGA devices using a hand held hot air rework station. — Preceding unsigned comment added by 138.38.32.168 (talk) 08:40, 26 July 2011 (UTC)

You are right. I have softened the wording a little. HumphreyW (talk) 10:03, 26 July 2011 (UTC)

Errors in materials

>Some of these dielectrics are polytetrafluoroethylene (Teflon), FR-4, FR-1, CEM-1 or CEM-3.

PTFE is only used in high performance PCB for ultra high frequencies. One supplier is i.e. http://www.rogerscorp.com . Cost can be easily over US$1000 per raw sheet. Beside PTFE there are a few other exotic materials.

>FR-2 (Phenolic cotton paper), FR-3 (Cotton paper and epoxy)

XPC, FR-1, FR-2, FR-3, CEM-1 use cellulose paper, not cotton paper.

> CEM-3 (Woven glass and epoxy)

CEM-3 uses a glass felt and not woven glass. — Preceding unsigned comment added by 203.198.92.79 (talk) 03:21, 4 August 2011 (UTC)

Breakout Boards

Why does Breakout Boards redirect to here? This article does not use the term Breakout Board, which means anyone coming to the article redirected from "Breakout Board" will be confused into thinking there might be information about Breakout Boards here. — Preceding unsigned comment added by 24.90.207.40 (talk) 07:02, 11 September 2011 (UTC)

Multiwire section does not belong here

The Multiwire board section does not belong here; it is not a printed wiring technology. It should be mentioned in the wirewrap article. Multiwire board may deserve an article of its own.

The redirect at Multiwire should be a dab.

Glrx (talk) 15:45, 29 September 2011 (UTC)

Maybe a short section on alternatives to printed wiring would be useful with links to other articles where they exist. Spinning Spark 20:24, 29 September 2011 (UTC)

Reliable sources needed

<ref> (original internal documentation of inventor Seymour Golub and NOMA catalog) </ref> is not a usable citation. A citation tells you how to find the original document; this doesn't even tell us which edition of a "NOMA catalog" to look for. --Wtshymanski (talk) 13:20, 7 October 2011 (UTC)

Party Quiz Game

I have moved the following from the article for discussion here first:-

NOMA Electic Company, NY, NY unwittingly produced the first commercial printed circuit board in 1946 with its Party Quiz Game. It was an electrical board game with replaceable question cards and two electrodes which, when placed in the proper positions to answer a question correctly, caused a bulb to light. Initially hardwired, the game was made thinner by hot pressing aluminum foil into a shirt cardboard with the electrical contacts made into the board.^{[citation needed]}<ref> (original internal documentation of inventor Seymour Golub and NOMA catalog) </ref>

The main question here is that aluminium foil pressed into cardboard may look superficially like a pcb, but was it produced by a printing process? Are there any reliable sources describing this as a "printed circuit"?
The reference cited is useless. No information allowing it to be found for verification such as title, date of publication, publisher, index number such as ISBN, ISSN or OCLC, or hyperlink is provided. Even if it could be verified, company internal documents and catalogs are generally not considered reliable sources.
I am sure NOMA Electric did not unwittingly invent this - they quite deliberately intended to manufacture exactly what was produced. It seems to me to be a later synthesis to describe this as "printed circuit.
Spinning Spark 16:34, 7 October 2011 (UTC)

Suggest merge

Through-hole technology mostly duplicates what is already here. It could be merged for context and coherence. --Wtshymanski (talk) 19:30, 20 December 2011 (UTC)

Oppose Duplication is mostly left-overs from when you already tried to merge it with one of your unattributed copy-pastes.

PCBs are a huge topic that should rightly spread several articles to give well-structured coverage. Through-hole is rightly one of those. Andy Dingley (talk) 10:58, 31 December 2011 (UTC)

Well, all PCBs were through-hole until surface mounting came out of the niche aerospace/hybrid ICs area. Any worthwhile discussion of printed circuit board manufacture is going to spend a lot of time talking about making and plating holes, which is pretty much the whole contents of the through-hole article. PCBs are indeed a huge topic but we're not expected to cover it all in a general encyclopedia article. And as is ever true in Wikipedia electronics articles, we spend lots of space on "what" (including useful rules-of-thumb for sizing holes), but never explain *why*. --Wtshymanski (talk) 18:47, 31 December 2011 (UTC)

They weren't all through-hole. Some of the very earliest (to avoid the time-consuming drilling) were more like tag strip. As you have already managed to confuse through-hole and plated-through-hole, I have to question your technical knowledge to make technical judgement calls in this field. Andy Dingley (talk) 19:39, 31 December 2011 (UTC)

Oppose. Through-hole technology is long enough and detailed enough to stand on its own. Spinning Spark 19:19, 31 December 2011 (UTC)

Oppose. THT could cover a lot more than it does -- material that would bog down PCB. Glrx (talk) 20:53, 1 January 2012 (UTC)
- It would help if you could give some examples. What should be added, that's not how-to or textbook material? --Wtshymanski (talk) 19:56, 2 January 2012 (UTC)

Lead benders, insertion equipment (even manual such as DIP inserters), cinchers, wave solder (compare IR/vapor surface mount soldering). Glrx (talk) 20:33, 3 January 2012 (UTC)

Oppose - I've added several sources to improve the Through-hole technology article. Through hole technology is significant because it almost completely replaced earlier electronics assembly techniques. Thus, as very a notable topic in its own right, it is worthy of its its own article. Northamerica1000^(talk) 06:22, 11 January 2012 (UTC)

Comment by nominator I find it very amusing that Wikipedia gives the impression that "through-hole techology" is somehow a separate topic from "printed circuit boards". "Through-hole technology" is a term coined for "the way every single PCB was ever made except for surface mount, and even they have holes in them" - but the Wikisages have spoken. --Wtshymanski (talk) 15:01, 11 January 2012 (UTC)

Multilayer boards?

Hardly any information. — Preceding unsigned comment added by 69.150.170.241 (talk) 09:24, 11 January 2012 (UTC)

Buy a book if you want infomation. The lowest-rent TAB paperback at least was written by an identifiable professional author and professional editor. Getting information from a Wikipedia article is like asking the guy sitting on the next bar stool. --Wtshymanski (talk) 15:03, 11 January 2012 (UTC)

I can work on that. I've designed too many multi-layers. See suggestion below. -- :- ) Don 21:27, 8 August 2012 (UTC)

Reorganize

This page is a bit confusing with pieces of the processing out of order and scattered here and there. I think it would be more understandable if it was arranged in the order of operations with the most common variations listed in each appropriate section. Drill => Plate => Etch => Mask => Legend. Multi-layer is not talked about much, but probably accounts for 50-75% of the PWB dollar volume produced today. That would require the addition of Image => Laminate before the standard processing described above. Or, in the case of blind vias, Drill => Image => Plate => Laminate.

Yeah/Nay? -- :- ) Don 21:24, 8 August 2012 (UTC)

Go for it!. As always, references and citations would be nice. Any history you run across would be of great interest. We've got a great deal of "what" but never enough answers to "why" in most electrical articles. Any annual volume estimates would be also interesting - just how many billion dollars worth of PCBs are made today, compared to, oh, say, 1962? 1952? --Wtshymanski (talk) 14:50, 9 August 2012 (UTC)

I did it again. :-( I don't have time to do the things already on my lists. However, I have added this article and will poke at if from time to time. -- :- ) Don 15:53, 9 August 2012 (UTC)

Can we just link to this? It looks good and comprehensive. -- :- ) Don 03:56, 3 October 2012 (UTC)

Here are a series of images I have been working on. This is start of panel plating. I figure to include a top view also above each section view. I know there are technical problems, but general comments? Then we can get to technical issues. Thanks. -- :- ) Don 15:51, 14 October 2012 (UTC)

This works. -- :- ) Don 21:40, 14 October 2012 (UTC)

Panel plating processing steps

Vital Articles

This article is in the Vital articles list. Ideally vital articles should be "Feature Class". This should be better than its current Class-C or Class-B. We need diagrams, flow charts, pictures. I have been working on some flow charts and processing pictorials. Any ideas on how these could be presented? There are many variations, I hate to clutter up pages with too many. Something like the collapsible lists, but how to do with .PNG's? I don't think pop-ups are allowed. Sub-pages may be too slow. HTML5 has lot of options available, but I'm not sure what Media-wiki's implementation plans are. -- :- ) Don 05:31, 14 October 2012 (UTC)

Feedback from reader

71.230.79.235 did not find what they were looking for. 6 days ago

Regarding your description for printed circuits, it was my understanding that Harry Rubinstein was credited by the IEEE in 1984 with the invention. http://www.ieee.org/documents/brunetti_rl.pdf 1984 - HARRY W. RUBINSTEIN Sprague Electric Co. Grafton, Wisconsin "For early key contributions to the development of printed components and conductors on a common insulating substrate." Here's a note from an award ceremony from the University of Wisconsin alluding to this fact. HARRY W. RUBINSTEIN For his innovations in the technology of printed electronic circuits and the fabrication of capacitors. Harry W. Rubinstein (BSEE '27) was president of Sprague Electric Company, Grafton, Wisconsin, from 1952 until 1970. He retired in 1971. Faced with problems of weight, space, and shortage of strategic materials, he developed the printed electronic circuit for the proximity fuse used in bombs in World War II. That project, in addition to the work of the National Bureau of Standards, was the forerunner of the laminated plastic base printed circuits so widely used today. In 1946, he was a cofounder of Herlec Corporation, which concentrated on manufacturing and distributing ceramic disc capacitors. Herlec merged with Sprague Electric in 1948. Mr. Rubinstein was responsible for Sprague's Grafton, Wisconsin, plant, set up factories in Nashua, New Hampshire, and Hillsville. Virginia, and was a consultant to many of Sprague's 31 factories worldwide. He helped improve manufacturing processes, reduce costs, and avoid duplication of facilities and effort. He holds 19 U.S. patents. He and his wife Else have a daughter and two sons. http://www.engr.wisc.edu/eday/eday1984.html I would have thought this information would be found on this site: http://en.wikipedia.org/wiki/Printed_circuit_board Thanks. Dr. Cohen

I see User:Ocyan already added. I need to check some of his patents, to ensure they are relevant to the current technology, he could have been printing capacitors. -- :- ) Don 05:56, 14 October 2012 (UTC)

PWB and PCB

This article talks mainly about a PCB although the technology, point to point connectivity, it technically a PWB (Printed Wiring Board). A PCB (Printed Circuit Board) is a board that has a printed RF element on it. Also, technically an assembly for these boards is a CCA (Circuit Card Assembly) or in the case of a backplane a Backplane Assembly as defined by H6 (http://www.dlis.dla.mil/H6/search.aspx). — Preceding unsigned comment added by Jschwa01 (talk • contribs) 20:41, 10 August 2011 (UTC)

That link is dead. I think you need to provide sources saying your definitions are widely used. As far as I am concerned PCB is the universally used term with PWB occasionally found in military specifications. The IPC may have created definitions but there is no evidence that anyone actually uses them. Spinning Spark 15:53, 15 August 2011 (UTC)

Umm... actually the term PWB is still in active use - it just depends what part of the world you are in. We use it throughout our commercial design practice...63.133.161.234 (talk) 18:06, 10 April 2013 (UTC)

Jschwa01 is technically correct. They've always been PWB's and PWA's(Printed Wiring Assembly) or CCA's to me and the military and aviation industry. But, PCB is the common everyday term used. -- :- ) Don 21:07, 8 August 2012 (UTC)

pcb masking using laser prints on plain paper made translucent with oil

I added an item listing this as a technique that can be used to make PCBs. I know it to work and I learned about it from a forum. I cannot (yet) cite a published reference.

Somebody anonymous removed this entry without any reference to me or making any note of what they did and why that I have found. As this was my first ever update to Wikipedia I am somewhat miffed. Is this how you treat contributors?

The normal approach when a citation is missing seems to be to add 'citation needed'. However, given that the entry was under the heading 'hobbyist', how likely do you think it is that hobbyists will bother to formally publish their findings? The particular entry is important because it reduces the cost of making PCBs in small quantities dramatically.

Another Geoff (talk) 12:18, 1 May 2013 (UTC)

Sorry this has happened to you on your first edit, this is a common experience for newbies. The reverting user is not anonymous, their name and reason can be found in the page history. The reason given for the revert in this edit is "odd/uncommon method; unsourced". Whether to apply the {{cn}} template or just remove the material is a matter of editorial judgement and personality of the editor concerned. Personally, I think templates should be used if one thinks the material is likely to be true and referenceable, and is relevant to the article. There is no rule requiring discussion prior to removal, but there is a rule requiring a citation to be provided before reinsertion - see WP:V. References are not required to be peer reviewed (although that helps a lot), they are only required to be reliable - but that does not include forums. If the information cannot be verified in a reliable source then it does not belong in Wikipedia. Sorry, that's the way we work. Spinning Spark 14:54, 1 May 2013 (UTC)

The odd thing is that I added a third item under two pre-existing others, neither of which had references or requests for citation. One rule for some it seems. The information I added was hardly contentious, it can be verified in a few seconds that putting olive oil onto plain paper makes it translucent.Another Geoff (talk) 16:07, 1 May 2013 (UTC)

There is no question of "one rule for some". Anyone is entitled to challenge material they think is dubious or insufficiently notable. Just because no one has challenged it so far does not mean it has some special privilege, but if no one challenges it ever, then it's fine to stay. It is not a question either, of me doing an experiment in my kitchen to verify you are right - I'm sure you are. Verification is required from a reliable source, not our own original research. This can be frustating at times on Wikipedia, for instance primary line constants has an empty section tag. Now I know perfectly well how to make these measurements, I used to do it as part of my profession. But I am trying to get the article to Good Article status so I cannot write uncited material into it. Spinning Spark 17:41, 1 May 2013 (UTC)

I'm the editor who reverted, and I certainly do not want you to feel unwelcome here. I do not doubt that the oil method can work, but I do not see it as a common practice. WP is not a catalog of all possible construction methods. Glrx (talk) 03:10, 2 May 2013 (UTC)

IPC terminology

I have just copyedited the recent insertion in the lede about IPC terminology. It now reads,

The IPC preferred term for populated boards is CCA, circuit card assembly.[1] This does not apply to backplanes; asssembled backplanes are called backplane assemblies by the IPC.

However, my impression from this is that the IPC is describing card racks (why is that a redlink by the way?) and the cards that go in them, not PCBs in general. Also, I am not convinced that this terminology is in widespread enough use to go in the lede anyway. Our article should not be driven by how the IPC would like the world to be, but rather how it actually is. Spinning Spark 12:38, 21 June 2013 (UTC)

Yes, IPC tends to spew specs (specifications), whether needed or not. From time to time, one of their specs stick.
Card rack is either embarrassed or the page does not exist.
Lede = Lead?? -- :- ) Don 14:27, 23 June 2013 (UTC)
- - "Lede" is a print industry spelling of "lead", allegedly instituted to avoid stupid print workers becoming confused and prematurely starting to pour hot lead. Spinning Spark 19:23, 23 June 2013 (UTC)

So shall we remove it? Spinning Spark 19:23, 23 June 2013 (UTC)

Earlier era tag type circuit assembly processes?

What is "earlier era tag type circuit assembly processes"? can't find on web at all... 71.139.166.154 (talk) 22:47, 28 August 2013 (UTC)

"tag strip" might find it.

Metal contacts (usually two solder eyelets and a rivet) were mechanically attached to paxolin insulating board. These boards were standard and the tags were in fixed one- or two-row layouts. Components were soldered between these tags. Andy Dingley (talk) 23:05, 28 August 2013 (UTC)

Actually, mass-produced items like TVs mostly used the tags on the components bolted or riveted to the chassis (valve holders and large electrolytics etc). Very few tag strips were used in such products. Tag strips were mostly used for prototyping or small scale and custom production. Spinning Spark 08:55, 29 August 2013 (UTC)

If you look at "turret tags", these were the densest form of tag strip. The tags were small cylindrical pins with a forked end rather than an eyelet. They were used in two rows on a board, with enough space between for components. This was (and still is) a common form of electronics construction for avionics and military in the 1950s and 1960s, still in production in the 1980s at least and still being serviced for front-line use today. Andy Dingley (talk) 10:49, 29 August 2013 (UTC)

Laminates

I think the section on laminates is too detailed for an encyclopedic article. I suggest to remove the table and other technical details. Burning objections, anyone? Karloman2 (talk) 20:53, 31 August 2013 (UTC)

I think you are right that it is too detailed for this article, but I hate to see information removed altogether. Moving to a separate page would be preferable, perhaps along with some of the text and just leave a summary here. Spinning Spark 21:13, 31 August 2013 (UTC)

I fully agree that it would be a pity to throw away the information. The question is where to put it. It is barely worth a separate article. There is an article on laminates, but this is very general; maybe I could create a chapter on PCB laminates and copy the content there. However, I don't want to spend too much time on this. Any suggestions? Karloman2 (talk) 22:02, 31 August 2013 (UTC)

There is enough variation and specialisation in PCB laminates (high frequency low loss for instance) to make a worthwile article. But you don't have to write it now, a stub article is fine. My suggestion would be to copy the entire section "as is" to a new page then reduce what we have here to a summary. That involves the bare minimum of effort (other than do nothing). When creating the new article don't forget to state in the edit summary that it is being pasted from printed circuit board. This is needed for licencing reasons. You should also link printed circuit board somewhere in the new article and add {{main}} to point to it from the summary in this article. Spinning Spark 15:43, 1 September 2013 (UTC)

Makes sens, I will do that when I have some time. Karloman2 (talk) 09:03, 2 September 2013 (UTC)

Chordwood and Multiwire

Multiwire has nothing to do with PCB. Chordwood may or may not use a PCB, but it is not a PCB, and many manufacturing methods use PCB's. IMHO multiwire and chordwood have no place in a PCB article. I suggest to move them to separate articles. Burning objections, anyone? Karloman2 (talk) 22:08, 31 August 2013 (UTC)

They justify a brief para or two, and that's what they have. Andy Dingley (talk) 22:38, 31 August 2013 (UTC)

They do justify the amount of words spent on them. But what is it doing on a PCB page? Multiwire is an alternate connection technology, just as wire-wrap is, or stripboard, or breadboard. The same holds for chordwood. Neither multiwire or chordwood are PCBs. So I suggest to move them to a separate article, just like wire-wrap, stripboard and breadboard have a separate article. (Maybe a good soul will make an overview article of connection methods, historic and actual.) OK? Karloman2 (talk) 22:57, 31 August 2013 (UTC)

Isn't the example image of cordwood implemented in PCB? That makes it relevant to this article. I agree with Andy that a brief section on alternative methods is useful. PCB technology has become so ubiquitous nowadays that readers may well run away with the idea that it is the only way that electronics is done. Perhaps they should both be under one heading that makes it clear that these are alternatives to pcbs rather than variations. Spinning Spark 15:27, 1 September 2013 (UTC)

I've rarely seen cordwood that wasn't a PCB (sometimes crossed stripboard for diode matrices). Tag strip and turret board were often used very similarly to cordwood (large tight-packed components in a neat grid and random wiring between them), but in a less dense 2D than the 3D shown here.

Well, I understood cordwood uses PCB, but is not a PCB. This article is not about the myriad items that use a PCB. But then, admittedly, I never saw a cordwood, and I may be wrong. But then the cordwood section need some work. But whatever, I will of course bow a consensus.Karloman2 (talk) 16:08, 1 September 2013 (UTC)

Cordwood is an assembly method, as is printed boards. It is not to be compared to the numerous applications of PCBs. Spinning Spark 08:40, 2 September 2013 (UTC)

An assembly method seems indeed what it is. Do you propose to keep it in the PCB article, or make it a separate article? Karloman2 (talk) 09:00, 2 September 2013 (UTC)

As to Multiwire, then isn't that a PCB anyway? Not an etched PCB, or even a subtractive PCB, but still a PCB. Andy Dingley (talk) 15:56, 1 September 2013 (UTC)

Hmmm, it is connection method and it is board, just like a breaboard. But it is not a PCB, as defined in the beginning of the article: "A printed circuit board, or PCB, is used to mechanically support and electrically connect electronic components using conductive pathways, tracks or signal traces etched from copper sheets laminated onto a non-conductive substrate." But again, I am sure both positions have some merit, let us see if there are some other voices.Karloman2 (talk) 16:08, 1 September 2013 (UTC)

Multiwire is a bit more dubious, which is why I suggest describing it as an alternative rather than a variation. But I do take issue with your principle that we should exclude anything that does not meet the definition in the lede. Would you, for instance, exclude additive processes, which do not meet that definition but are unarguably printed processes, or would you conclude that the definition is deficient and amend that instead? Spinning Spark 08:40, 2 September 2013 (UTC)

True. Do you propose to keep it in the PCB article, or make it a separate article? Karloman2 (talk) 09:00, 2 September 2013 (UTC)

I wasn't proposing doing anything, I was responding to your proposal. To answer you, I think cordwood should be kept in this article. Multiwire could be moved to a stub article or kept here, I am neutral. If kept, it should be under an "alternative technologies" heading. If moved, we can still usefully maintain a list of alternative technologies with links to articles where they exist. Spinning Spark 16:53, 2 September 2013 (UTC)

I will leave the article as is. For me this section is closed.Karloman2 (talk) 06:42, 3 September 2013 (UTC)

Undo on 2-Sep-2013

My last edit was undone. It did two things on the intro section of the article.

The intro contains "Printed circuit" redirects here. For the defunct company, see Printed Circuit Corporation. I removed this. Other entries such as PWB also redirect to this article. I do not thing the reader cares. It is not clear to me why Printed Circuit Corporation is so important it deserves such a prominent mentions, or even a mention at all. There are hundreds of defunct PCB manufacturers in the west.

The intro also contains They therefore are cheaper, faster to manufacture and potentially more reliable for high-volume production. I changed this in They therefore are cheaper, faster to manufacture and potentially more reliable. (Admittedly, I forgot to mention this, sorry for that.) These benefits also hold for medium, small and very small volumes. I think adding the volume stuff is misleading. Of course, both version are unreferenced.

I think the changes made the intro more concise and more correct.

However, I certainly do not want to start an undo war, so I leave this to the community. (I will no longer edit this article in the foreseeable future.) Karloman2 (talk) 08:48, 3 September 2013 (UTC)

It was me who reverted you here. Taking your second point first, your edit summary says "Remove self-redirect" and since this was clearly nothing to do with removing a self-redirect and deleted material without inserting anything, I concluded (apparently incorrectly) that that was merely an accident. Feel free to restore that part of your edit.

As for the hatnote, I sympathise with the feeling that hatnotes can give prominence to trivial unrelated subjects, but this is the standard method of disambiguation on Wikipedia. If you want to change that you need to get the WP:DAB guideline changed. The alternative method is to have a disambiguation page at printed circuit (as there once was), but in my opinion this article is the main meaning of the term and it should therefore redirect here, so a hatnote pointing to the disambiguation page would still be needed. Also, since the number of terms needing disambiguation has been reduced to just one, a hatnote for it is the really the only way to go.

Printed Circuit Corporation needs disambiguating because a user could plausibly enter Printed Circuit as a search term and will end up at this article instead (different capitalisation rules apply in the search box compared to redlinks). This has nothing to do with whether or not the company makes PCBs. It is solely because the names are similar. On the other hand PWB does not need disambiguating here because it does not redirect here, but rather, takes the reader to a disambiguation page. Spinning Spark 16:02, 3 September 2013 (UTC)

On the hatnote. What you write makes a lot of sense. So be it.

On the other removed words. I will do as you suggest and restore that part of the edit. But this is really my last edit in the foreseeable time. Other work, and all that. Karloman2 (talk) 16:44, 3 September 2013 (UTC)

Most common process

This edit recently removed "The majority of printed circuit boards today are made from purchased laminate material with copper already applied to both sides" and now states that the semi-additive process is the most common process. Is this true, and if so can we have a cite for this please? I am not current enough to know if this is right, but it always used to be the case that the pcb process would start with copper-clad laminate board. It is possible the editor may have mistakenly copyedited the statement that the semi-additive process is the most common additive process into it is the most common process. Spinning Spark 07:51, 4 October 2013 (UTC)

Hi. I indeed removed the sentence "The majority...". This is not because it is wrong, but because it does not contribute to this section. Maybe is has a place in the materials section. It is confusing because additive processes do not start from such material; this is my main objection to this sentence, and the reason I removed it.

About the most common process. The original article already stated that semi-additive is the most common process. I simply left it in place. Apart from that,I believe it is true.In the west it is in nearly universal use. Japan uses a lot of panel plating, which is more subtractive. I have no references. However, I am not sure if this is true or not, which is why I left this as it is.212.78.197.250 (talk) 08:57, 4 October 2013 (UTC)

Under the original structure it was a paragraph under additive processes so it clearly originally meant it was the most common additive process. You have changed the meaning and I don't think you should do that unless you have a source or are sure of your facts. Spinning Spark 13:28, 4 October 2013 (UTC)

Weak points

Appearantly, companies introduce weak points in PCB's/consumer electronics they design so the device becomes defect quicker, with the result that the consumer need to buy new devices quicker. Appearantly , in motherboards it's mostly caused by capacitors they place on the boards (not sure why these are needed at all). Perhaps mention in article. KVDP (talk) 17:44, 16 February 2014 (UTC)

I've never heard anything so dumb. See Capacitor#Applications. Spinning Spark 23:52, 16 February 2014 (UTC)

Try Special:Contributions/KVDP. 8-(

KVDP, will you _please_ stop contributing to any sort of technical discussion until you stop being so clueless and gullible. Andy Dingley (talk) 00:09, 17 February 2014 (UTC)

English variety actually en-US?

First author is User:Ray Van De Walker whose page states he's US. first edit. Glrx (talk) 00:09, 30 April 2014 (UTC)

I was going by the spellings such as "labour" and the "-lly" ending already in the article. I did not see any unquestionably US spellings, so currently the article is UK spelling. That seems to have been established for a long time. WP:RETAIN does not say anything about the nationality of the first author. It advises against changing an established style. In the event of a dispute we should look at "the first post-stub contributor to introduce text written in a particular English variety". Is there a dispute? Spinning Spark 00:34, 30 April 2014 (UTC)

I questioned the pronouncement; I'm not big one way or the other. Using your word, there is one instance of "labour" and two instances of "labor". Glrx (talk) 23:05, 30 April 2014 (UTC)

There is? I missed that. Looking at the history, the first insertion of "labor" was in this rather substantial series of edits by user Hydrargyrum so I guess that means we should use US English. I have reverted my edit. Someone should go through the article and make it consistent, preferably a native US speaker. Spinning Spark 00:07, 1 May 2014 (UTC)

Thanks. I tagged this talk page as {{American English}}. Glrx (talk) 21:47, 1 May 2014 (UTC)

Reverted edits

I added some useful topics about precautions while using PCBs. Those has been removed. Please let me know the issue with the edits User talk:Pcbapc — Preceding undated comment added 07:10, 9 June 2014 (UTC)

Start by reading some of our guidelines: WP:V, WP:HOWTO, and MOS:YOU. That should explain most of where you are going wrong. Spinning Spark 11:59, 9 June 2014 (UTC)

Patterning methods

The current text on patterning method by volume contains the following:

Large volume

   Silk screen printing–the main commercial method.
   Photoengraving–used when fine linewidths are required.

I do not believe that silk screen printing is the main method, I believe photo-engraving is. (The statement is unreferenced.) I know quite a number of manufacturers, and few use silk screen printing, but I have no statistics, proof or references. Consequently, I am not comfortable to make statements about this. Still, I would like to change the text as follows, sidestepping the volume question.

Large volume

   Photoengraving – used when fine line widths are required.
   Silk screen printing – used for PCBs with thicker lines.

Are there burning objections? Or does anyone has references about this?

Karloman2 (talk) 16:25, 23 January 2015 (UTC)

As there are no objections, I will now make this change.

Karloman2 (talk) 08:37, 8 February 2015 (UTC)

Placement of history section

An IP editor recently tried to move the history section to the top [1]. That was reverted by User:Karloman2 with the comment "I dont think history comes first. People looking at this article are probably not interested in the history." I agree that history should not be at the very top, but on the other hand I don't necessarily agree that it should be relegated to the very bottom. There should be enough in front of history to explain what the subject is all about and introduce terms that might be used in the history. Karloman, you are making assumptions about why readers come to an article. Those who work with pcbs and understand the technicalities would be ill advised to come to Wikipedia for technical information. For the general reader of a technical article, the history is often the most accessible and easily understood part of the article. It may even be what they came to the article to find. SpinningSpark 07:57, 6 September 2015 (UTC)

Well, one has to make assumptions on why readers come to an article, I think, otherwise it is not possible to write it. One can only hope these assumptions are not too far off. Whatever, I fully agree with you that the history must not necessarily be put at the very bottom. I suggest putting it just after, or maybe just before, the section "PCB Characteristics".Karloman2 (talk) 10:22, 7 September 2015 (UTC)

Opaque ink pens were also used

Straight onto boards before exposing them, I laid out my first that way. did my 2nd with 1:1 tape onto a board (1 sided, early-mid '70s). And for photo-lithography, I'll bet freehand drawing was used as well, the Flipchip in the 2nd photo looks like it might have been hand drawn, not done with tape. Note the short thick section in the bottom trace, inconsistent with tape, but not with pen and ink, and in general doing curves like that with tape would have been a real pain. Hga (talk) 19:17, 8 November 2015 (UTC)

I've still got such a pen. Don't think that it's a viable technique any more though, electronics has got too small for that. I don't think you are right about the board being done freehand. The roundels are too round and the trace widths are too consistent. The thick piece you point out looks like a solder blob to me. Curves are actually quite easy with crepe tape, which is what we used to use, especially with thinner traces like on this board. The clincher for me is that the top trace goes off the boundary of the board, a very unlikely mistake for someone drawing directly on to the surface. SpinningSpark 20:28, 8 November 2015 (UTC)

Good but rationalization would be an improvement

It is obvious that a lot of work has gone into this article and there is a load of good information, but suggest that some rationalization of the the content/heads would make it more readable. A bit of copy editing here and there would help too. CPES (talk) 10:49, 9 June 2016 (UTC)

You're doing a good job, but it is my non-expert and possibly incorrect recollection that when using IR reflow on surface mount PCBs, that glue is not always necessary; the solder paste has sufficient adhesion for small parts. Not so? Constant314 (talk) 12:01, 9 June 2016 (UTC)

Decreasing trace impedance is not correct

Currently the articles states that "The impedance of transmission lines decreases with frequency", even though earlier it is stated that the dielectric constant (Dk) is "usually decreasing with frequency". Actually, if Dk decreases with frequency, that means the characteristic impedance will increase. Lower Dk means lower per-unit-length capacitance, which means higher sqrt(L/C).

The article should state that trace impedance will increase for typical materials which have Dk decreasing with frequency. — Preceding unsigned comment added by Mbleslie (talk • contribs) 17:49, 28 November 2016 (UTC)

Why are circuit boards usually green?

Potential sources:

Anyone interested in either writing this up, or researching further? :-) Quiddity (talk) 04:19, 26 August 2017 (UTC)

My recollection from the early 1970's is that Bakelite boards were brown and fiberglass boards were a pale gray green without the solder resist. I don't know why.Constant314 (talk) 22:30, 26 August 2017 (UTC)

Massive edit on December 5th by 173.59.13.98

The re-ordering of section is probably a good thing - the article could do with some reorganization. Adding an Overview section is a good idea. I did not look at the copy-edits, but I assume they are improvements. However, I have two remarks: 1) The new Overview section and the new words in the intro are wholly without references. Zero. I think that either references must be added, or the new content removed. 2) The intro section is now much longer than the original one, and somewhat rambling. The benefit of an Overview is that the intro can be short. Those that want to know more can go to the Overview. For a casual visitor, that wants quickly to know what a PCB is, I think the new intro is daunting. I suggest to drastically shorten it. Opinions? Ludwig Boltzmann (talk) 09:08, 7 December 2017 (UTC)

As the editor who made this "massive edit" (which indeed it is), I appreciate your constructive criticism, and I am pleased to see that since the major edit, the article seems to be evolving nicely and that my work (which took may hours of my time) appears to be generally appreciated. I welcome and invite more feedback by you and others.

And now, a (semi-)massive talk page entry. :) (Massivette?) (OK, as talk page entries go, it's really, really big.)

I am particularly happy that you appreciate my reorganization of the sections. I did notice that someone moved the History section back to the end. I think that is OK, but perhaps it would be better to place it somewhere above the very end. I had moved it to the top (after the Overview) because A) many other WP technical articles have a History section first, and B) there is a nice general cognitive flow from history to the PCB characteristics to the process of making a board from design layout through bare-board fabrication to populating, soldering, testing, and shipping.

Come to think of it, I didn't notice much in the article about packaging PCBA's for shipping, i.e. ESD protectio packaging, a box to protect against comprssion forces with bubble wrap or foam to protect against shock and vibration, etc. There is one paragraph that mentions ESD, but at present no link to a main article on that subject and little detail. I think "protection", in the sense of encapsulation as by conformal coating, and "packaging" should be separate subsections, and the latter should be about three paragraphs long. I didn't have time to thoroughly review and improve all of the article (and I spent over 4 hours as it was); as my edit summary says, the bulk of most of the detail section, I only copy edited. Even that, I did not do thoroughly, skimming some sections and probably missing some language flaws even in sections where I did make significant copy edits.

I have been a Wikipedia editor for many years. (So far, I choose to edit anonymously rather than to create an account.) As a typical modus operandi, I usually do not add references for general material that I add; I leave that to other editors. The main contribution I aim to make is in the writing—wording, organization, grammar, flow, etc.—and general information content, from my knowledge, which is deep in a number of areas. I generally do not write new content into articles about subjects with which I am not familiar, though I do often make copy edits for punctuation, grammar, and language anywhere I see them (which is to say, all over the place). My hope as I edit is that the community will decide that what I have added or changed improves the article enough that if it needs references in order to be retained, someone will find and add the appropriate references. If not, it can go (although I think that would be a waste, throwing away value). Usually my edits do not get reverted, though I have had a few civilized conflicts with other editors. Long ago, I found that the improvements I made were retained much more often than discarded, so I keep editing.

I should note that when I add material without citations, often it is common-sense deducible from facts alreday in the article or from common human experience or common knowledge (at least in modern America, and at least among those with some frequent contact with the relevant subject area). I do not add proprietary statistics or other obscure quantitative data without citations; it would be very difficult for anyone to find the correct source to add a reference, so that would just be bad citizenship (and a waste of time, since such uncited numbers should be deleted more quickly than they appeared).

Though I usually do not myself add citations to work that I add to a WP article, that is not always the case. Particularly in "legacy" computer-related subject areas, where I have many primary references on hand, I sometimes do add citations. (When I have added those, it was often more because I thought pointing the reader to the referenced technical document was valuable in itself, rather than because I thought it was a value to prove that the statement was authoritative. Not to say that the latter had no value; it just was not the majority of the value that I perceived. As I have said, there are so many unproven statement in non-Featured WP articles that my citing sources for one or two of them would be like painting a 2-foot-square patch of a living room wall a new color and hoping that would count as redecorating.) In one particular recent case, where I added a single important point (one or two sentences) to the article "Great Chicago Fire", without citations, only to have it reverted for lack of sources, I recognized that the criticism was valid: this particular point was sure to be controversial, and I thought the phrasing of the last clause I had written might technically be susceptible to a claim of original research. I reinstated the edit with five specific citations (found through other WP articles—the controversial claim at hand was well documented as a fact in multiple other WP articles) and a main-article reference to the WP article on the subject. In this case, this was my duty, and I accepted it gladly (enough), because I really wanted this oft-forgotten major point of historical fact to be included in the story; its absence made for a distorted view of the historical situation surrounding falsely-accused Mrs. O'Leary and her much-maligned cow. This goes to support two assertions: That I recognize when citations are truly needed, and that material that I add without citations is often valid enough to be worth either keeping as-is or researching to add references. (If I were getting paid to do the research, then I would. I'm not, so I'll do the work that I enjoy and appreciate, while others are free to do the work that they enjoy and/or appreciate.)

As for the introduction, I will admit that it was very long, as I wrote it. It was even longer in an earlier draft; I moved as much as I thought I could appropriately to the new Overview section. Now it has been cut down, by someone who simply discarded six whole paragraphs. This is not good; too much important material has been discarded, inclusing at least two paragraphs that were long-established before I ever saw the article. Breakout boards, which were discused on the talk page (archived), are gone. Terminology and the abiguity of "PCB" as populated or unpopulated, gone. Neither of these paragraphs were my insertions, though I edited them. Other paragraphs that I inserted are also entirely gone. Text into which hours of work was invested seems to have been deleted with minutes of consideration. I agree that the Introduction should be shorter than it was in my version, and more of the details that I left in it should be moved into the Overview or other specific detail sections, but the essential theses (asserted points of fact) of most of these sentences should be retained somewhere in the article.

Also, I added the paragraph which primarily defined the terms "populated" and "unpopulated" after noticing the first of these jargon terms used in the caption of the first image but not defined anywhere in the article. That paragraph was summarily deleted, apparently without recognizing its purpose and importance. Perhaps it could have been stripped down, but "populated" in this special sense must be defined before it is used in a caption, which means this definition must appear in the introduction, or the caption must change. In that case, perhaps a different image (one with both bare and populated boards) would be better.

I am tempted to revert that edit (02:08, 8 December 2017, by, Wtshymanski) but I don't want to appear to be edit warring, so I would prefer that someone else reinstate most of this content—the abstract content, not necessarily the language—in some form.

To digress for a moment, I find it slightly ironic that this image shows a PCB from a 1983 ZX Spectrum, yet the article seems to be written, and the History section placed, on the presumption that most readers will mainly be interested in modern PCB mass production. I would actually think the opposite: if you are going into industry, you are not going to use WP as a technical reference. Someone else said this in an archived talk page section. I think you would get a book (or books) from a major publisher, read Brittanica, or take a college course. I think the main audience for this article among WP readers consists of small business operators and employees, individuals doing projects, and students writing research papers, all of whom will be more interested in the fundamental properties, methods, and materials of PCBs and in the history of their development than in technical details of industrial volume production of PCBAs. An article must be written assuming some audience; this too was mentioned in the talk page archives. I think this one was largely written for the wrong audience. The Overview section that I added was mainly intended to address the audience of readers who want a reasonably thorough but only moderately detailed picture of the whole sphere of printed circuit boards, including what exactly they are, how they work, how they are assembled, and how they are used. I envisioned that many readers (who do not want to read all the detail in the main sections that were present before my major edit) would read only the introduction and Overview, being satisified to have all the information they needed.

I also think that an unbiased article should not pressume a general focus or worldview. Not everybody thinks that industrial business is the center of the world and human society. (Some people think that human actions and interactions are the center.) By eliminating prototyping and manual production, the article gives the imprssion that printed circuit boards are exclusively a large-scale industrial technology, and by only focusing on the advantages of this modern technology, the article subtly promotes the cult of the new, all instead of aiming for a balanced objective view. There are a lot of great things about PCBs, but there are also some some really lousy things about them, for some purposes, for which older technologies, or simpler (one or two-sided) PCB technologies, are better. PCB circuits are harder to modify and repair than point-to-point circuits or wire-wrap circuits. Modern industry has all but abandoned the concept of repair, so it doesn't care, but not all individual citizens agree with and follow the lead of modern industry. Circuits on multi-layer boards are nearly impossible to modify in major ways, and very difficult to analyze (especially with field equipment, as opposed to million dollar industrial test hardware). For people who like to have control over their machinery, to understand fully how it works, and to maintain it by personal effort both while and long after it has industry support, this technology (multilayer PCBs with SMDs) can be a major obstacle and a gross, unquestionable disadvantage over earlier technologies. Industry certainly can't be expected to embrace earlier methods again, even for limited applications, but that doesn't change the fact that pretending the newest technology is universally and unequivocally "just better" is biased and not the truth. The article does not even hint that there is any perspective other than the mass industry (throw-away society) perspective. And I did not add this to the article, because I have no published sources for it, so it would probably be challenged as original research, which frankly, it might be to some extent. But can we try to move a little closer to unbiased objectivity? PCBs are a lot of things to a lot of people, precisely because they are ubiquitous, and it would be nice if someone would add some of that diversity to this article, with sources. I, for myself, have already spent too much time on it, and probably will not get around to working on this.

Getting back to discussing the "massive edit", I agree that as that the introduction, as I submitted it, was too long, perhaps even "daunting" to some readers. (After so many hours of work, you have other things to do, and you have to submit something less perfect than you would like, so long as you are confident it is an improvement over what it is replacing.)

I fully agree that the advantage of an Overview is that the introduction can be short, and I fully endorse the movement of as much introductory content as possible, other than the first paragraph and maybe one or two more key paragraphs, into the Overview. Perhaps to do this well, the overview should be divided into two or three subsections: terminology and applications, physical description and characteristics (i.e. abstract concepts), design and fabrication processes and techniques.

The problem was that the article prior to my big edit did not serve the casual visitor well. The introduction was at once too technical (and industry-myopic) and too patchy, covering some facets well and others not at all. The first paragraph hits on all the main points but is not really illuminative for someone who is not already familiar with printed circuit boards, and the rest of the introduction before I edited it did not really change that. This was what spurred me to make a major edit to the article in the first place. The body of the article had (and retains) some good, solid detail material, but the introduction was mediocre. I worked on describing the subject and the set of concepts surrounding it in a way that would be complete and fully comprehensible to a person who had no knowledge of it beforehand. "Printed circuit board? What's that? Is that one of those gizmos they use in inkjet printers?" To a person familiar with a thing, there are a lot of aspects and details that are so intrisic to your concept of it that you don't even realize they are not obvious, but they are not, so they need to be stated. I think the introduction and overview together were good, maybe very good, but not great the way I left them; there was the potential to daunt the casual reader. I think now they are just good; they are missing some important information.

173.59.13.98 (talk) 13:18, 8 December 2017 (UTC)

I thank ‎Wtshymanski for cutting back the intro to a suitable length. ‎Ludwig Boltzmann (talk) 16:32, 8 December 2017 (UTC)

Seeing that it seems to be what the people want, I have stripped the intro down even further. Anything that might not be a loss, I cut. (Unfortunately, already stripped data doesn't compress much further.) Also put in 2 short sentences hinting at neutral balance, one replacing a cut sentence. I do think now the intro is much better than I first left it. I have also resurrected those two paragraphs I didn't originate, to the Overview, while cutting some other parts of the Overview a little bit. And if we don't define "populate" until halfway through the article, we should refrain from using it until then: Done. (I also tried to delete a lot of my massivette treatise of earlier today, since I get it that "no one" is going to read through most of it, especially those parts I tried to cut, so why make them scroll past it? But "a filter" won't let one edit even one's own words on talk pages, even the same day, so that's that.)

Shame there isn't more detailed feedback & editing coordination here. That's it for me; been wasting too much time. At least the article is a lot better than it was before the 5th, and that will probably benefit many people. Over & out. 173.59.13.98 (talk) 20:49, 8 December 2017 (UTC)

Judgy

Obviously the best material for a printed circuit board is fused corundum, plated in pure silver-109, hand-etched by Circassian virgins of noble birth. Back in the real world, you use the material that does the job; a mouse won't work any better with an FR 4 or Teflon circuit board. Anyone who's lived long enough on this planet to learn to read has also learned their are cheap things and expensive things. We dn't need to beat this over the reader's head. --Wtshymanski (talk) 21:21, 20 December 2017 (UTC)

Reference 14

There is a sentence that states the IPC standard is to use the term CCA and the reference states IPC-14.38. IPC-14 does not appear to fit the IPC numbering system and is not listed in the IPC Standards Tree. — Preceding unsigned comment added by 67.30.143.130 (talk) 15:34, 15 March 2019 (UTC)

The recent copy and paste from the website www.911eda.com is a copyright violation. Since the material appeared in a copyrighted website, the material is considered copyrighted for Wikipedia purposes. The policy is designed to keep Wikipedia out of legal trouble. However, if you are the owner of the copyright, you can give Wikipedia permission to publish the material. There is a little bit of bureaucratic record keeping, but it is straight forward. See Wikipedia:Requesting copyright permission. The purpose is to establish that you are giving the proper rights to Wikipedia and understand what those rights are.

However, www.911eda.com is a commercial site offering services for sale. It would be considered SPAM to cite www.911eda.com as a source. So, you can use the material, with permission, but you need to cite reliable independent sources.

Since you appear to be associated with 911EDA, you need to adhere to conflict of interest WP:COI and WP:SPAM policies. Constant314 (talk) 20:00, 28 August 2019 (UTC)