History and "Design" aspect of PCB - Page 1
Forum section: electronics / general

author: nomis
author_rank: Contributor
timestamp: March 22, 2014, 02:02:22 pm
content: Hi all.I am currently working on a talk about the "Design" aspect of PCBs and how the tools used to design a PCB affect their appearance - with a slight focus on Fonts. It will be presented at the Libre Graphics Meeting, the annual conference on free software graphics tools (Gimp, Inkscape, Blender etc.) being held in Leipzig, Germany this year.Unfortunately I did not yet find any photos that show how PCBs were designed/made before the appearance of CAD as well as in the early days of CAD design.I would like to pick your minds and photo archives - can you make photos available to me that e.g. show an early Gerber plotter? Early PCB manufacturing? PCB that really show influences made by the tool used to design them?Also I'd like to showcase that the "design" aspect is important. So if you have any examples for a PCB that impress you on a artistic level, where the designer has gone the extra mile to make it beautiful I'd appreciate photos or references.If you can provide the photos under a creative commons lice that'd be great, but it is not strictly necessary.Thanks for your input.Bye,Simon (simon@gimp.org)

author: sync
author_rank: Frequent Contributor
timestamp: March 22, 2014, 02:21:22 pm
content: An old movie from Tektronix about PCB design and production.http://www.vintagetek.org/tektronix-printed-circuit-boards-1969/

author: Bloch
author_rank: Unknown
timestamp: March 23, 2014, 07:03:21 am
content: That a great link.I have read and heard about how it was done i the good old days.But a video is much better to understand how much easier it is today.

author: EEVblog
author_rank: Unknown
timestamp: March 23, 2014, 08:38:08 am
content: Bishop Graphics tapes on clear cellofilm over a light box was generally the way it was done post that video which is rather old school. This was used in the 70's and into the early 80's.Usually different colour tape and pads for each layer were used, and often done at double or more the real size. For common things like IC pads and TO-92 transistors you'd have templates you just peeled off and stuck down. Everyone had their own method about how they'd mock up the circuit beforehand etc. Personally I just went "straight to tape" and laid out the board directly from the schematic.The film was then photo-reduced onto a negative film. That negative film was then used to expose a negative photo resist coated copper clad PCB and etched as per usual.

author: nomis
author_rank: Contributor
timestamp: March 23, 2014, 12:12:01 pm
content: Quote from: sync on March 22, 2014, 02:21:22 pmThat movie is great, thanks for that.Quote from: EEVblog on March 23, 2014, 08:38:08 amThe production of the PCBs conceptually hasn't changed much over time since their invention, right? It today still is a process based on photographic film used to expose certain photo sensitive materials.What has changed a lot of course is how the design actually happens, today dominated by CAD tools. What I found striking is the visual difference between issue 1 and issue 3 of the ZX81:http://homepage.ntlworld.com/paul.a.kitching/temp/Cimg3394s.jpghttp://www.nightfallcrew.com/wp-content/gallery/sinclair-zx81-16k-ram/img_1811.jpgBetween these two issues obviously CAD happened... This is what I am referring to when talking about how the tool shapes the design...Bye,Simon

author: SeanB
author_rank: Super Contributor
timestamp: March 23, 2014, 12:30:56 pm
content: Cheap PCB's used to be made by punching out a design on a copper sheet, and laminating it to the bare SRBP board then curing the whole sandwich. Another method was to screen print a conductive pattern with ink onto the bare board then plating the whole thing with copper. The stamped boards had a rounded edge to the copper traces and the plated ones had a lot of extra holes that were drilled to separate the individual traces, leaving a lot of short traces leading to a drilled hole. these were all cheap low tolerance PCB's that had through hole parts, often found in mass produced products and most common as panels in cheap consumer stuff like a toy or radio. i have seen some in mass produced things like printers as the keyboard panel holding the switches.

author: AndyC_772
author_rank: Super Contributor
timestamp: March 23, 2014, 01:00:53 pm
content: One very important thing to bear in mind is that a PCB is absolutely, 100%, a functional thing rather than one which needs to have any artistic value - with the possible exception of boards which are sold uncased (such as PC components).The reason why it's so important to remember this, is that the requirements of the two are frequently in direct conflict. For example, it looks 'nice' if all the components in a given part of the board line up exactly. It looks 'right', or even 'more professional'. But if, in order to achieve that, traces have to be made longer, then the board is actually worse in terms of signal integrity, timing margins and EMC. Running traces together in a nice neat, tidy looking parallel bus is theworst possibleway to route them in terms of crosstalk.Laying out a PCB also takes time and effort, and making a board look "nice" uses these up for no commercial benefit. Once a board meets all the requirements of connectivity, signal integrity and mechanical layout, then it is complete, and going on from this point to make it look pretty is not time well spent. Electrons move around based on the laws of physics; they're not influenced by the aesthetic judgment of any person.Having said all that, every layout person I know - myself included - likes to make their boards look nice. It's seen as a mark of professionalism, and the fact that the design not only took longer but may also be objectively, quantifiably worse in the ways that really matter, is frequently overlooked.For what it's worth, fonts are completely irrelevant. They need to be large/bold enough to be clearly readable, and small enough to fit the physical space available - and that's about the only attention they ever receive. It might be possible to identify the CAD package that was used to generate a given board by looking at its font, but that's about it.

author: nomis
author_rank: Contributor
timestamp: March 24, 2014, 08:31:47 pm
content: Quote from: AndyC_772 on March 23, 2014, 01:00:53 pmWhile I see your point I tend to disagree. Obviously there is noneedto have any artistic value, but if it can be added without compromising too much on the functionality of the PCB I do appreciate it. Doubly so if it is invisble later - to me it is an indication that the author cared about his work and took it as important enough to invest time into aspects that are not strictly necessary.Quote from: AndyC_772 on March 23, 2014, 01:00:53 pmWell, Fonts are always irrelevant if you disregard the aesthetic value. That not only holds for PCBs but for newspapers as well. If design were irrelevant, everybody would e.g. use Times, which was expressly designed for the needs of a specific Newspaper.Indeed a huge aspect of font design is making them functional for a specific purpose. There are certain aspects to font design that relate to the printing process of newspapers. And the adoption of CAD resulted in a drastic change: suddenly it was a vital aspect for the font to be able to constructed with the CAD tools, resulting in the fonts built from straight lines we still see today.That is my main motivation for the talk: The introduction of CAD had a drastic negative impact on the font quality on PCBs. The universal exchange format for CAD data has no native support for bezier segments, the most important graphics primitive in other 2d vector graphics exchange formats.Yeah, that is unlikely to change, but I think it is worthwile to think about what is possible with the current state of the art.Bye,Simon

author: AndyC_772
author_rank: Super Contributor
timestamp: March 24, 2014, 09:23:12 pm
content: Don't get me wrong, I hear what you're saying, and I'm not entirely unfamiliar with the concept of putting effort into making quality engineering look nice as well. I think it's an area which is only really developed in "luxury" items, though, where customer perceptions and the "feel good" factor are as important as the functionality of the product.For example, I fully expect the parts of a mechanical Swiss watch to be highly polished and machined to within microns, even though I never see them. Knowing that they're there, and that they've received all that attention, is part of the product offering. And, of course, a watch made like that sells for 10 or 100 times the price of a quartz watch, which probably doesn't look so different on the outside, and actually keeps better time.I think it's probably fair to say that every product I've ever designed has been functional - first, last, and everything in between. People buy products I've worked on because of the features they have and the quantifiable aspects of quality: reliability, cost, size, power consumption and so on. My PCBs all live inside boxes, are never seen or even considered by the end customer unless they go wrong, and they are judged only by how well they work. And that's absolutely OK with me.If I were designing really high-end hi-fi, for example, then things might be different. I'd expect reviewers to be opening up the box and showing photos of the PCB to potential buyers, and I'd expect those buyers to judge the product based as much on how nice the board looks as on how the system sounds. I would indeed put a lot of time and effort into making parts line up, or to have circuits be exact mirror images of each other, or whatever - not because doing so improves the sound, but because non-engineers will look at it andperceiveit to be a quality product.Example: try an image search for "Oppo BDP-95", and look at the audio board. It's a high end Blu-ray player, and the manufacturer has clearly put a lot of effort into making this board look like what you might expect to find inside an expensive model. But there's no way that board is actually optimal from either a cost or performance point of view - it's twice the size it needs to be for starters, and long traces generally pick up and radiate more noise than short ones.I would suggest, though, that 99.9% of PCBs are never meant to be looked at, and nobody is ever willingly going to pay me for the time it would take to make a board which is a functional work of art. There is no reason to.On the subject of fonts, I completely agree that they're important when they're used in a medium where they'll actually be read and appreciated - but few people outside the industry ever even see a bare PCB, and when they do read the silk screen on the board it's for a purely functional reason.The lettering on a PCB needs to be clear (which is generally a limitation of the printing process, which varies a lot between PCB fabricators), and it needs to be positioned logically and correctly. The intended audience is a handful of people involved in the manufacturing chain, and they care about correctly identifying part numbers, component locations and so on.The end customer, whose opinion on aesthetics might actually matter, is unlikely to ever even see the board.For what it's worth, the CAD software I use offers no choice of fonts beyond size and line width. As you mention, characters are stored and reproduced as a series of straight lines, and that's it. I can import graphics from outside (such as a company logo), but even that is a time consuming process with multiple steps, and not something I would ever do just to change the look of my board even if I wanted to.Believe it or not I'm genuinely interested to hear what you find out, but I'm afraid I think you may be looking for ideas and inspiration in a pretty dry, empty place. Sorry.

author: nomis
author_rank: Contributor
timestamp: March 24, 2014, 11:41:25 pm
content: Quote from: AndyC_772 on March 24, 2014, 09:23:12 pmThat probably is true. I'd also like to point out the enthusiast/hobbyist range, where people design their PCBs without a ticking clock in the back of the head. I for myself consider me lucky, that I sometimes manage to dabble in PCB design and tremendously enjoy "wasting" my time in details nobody except me ever will notice - until I blab about themSo yes, we probably have very different approaches to that topic.Funnily if you've ever looked at an Arduino: It has tons of "artistic" silk screening on it. It has a pointless map of italy, lots of beautifully typeset text. It suddenly (accidentially) became a purpose: it makes counterfeiting hard:http://arduino.cc/en/Products/CounterfeitAlso I found this image of a vintage tektronix evaluation board athttp://modularsynthesis.com/tek/from before 1966. They have a detailed (apparently overetched) logo of their company on the board. Which probably makes sense if you're trying to test your processes, but then a test pattern even might have been more useful...There is a (for-the-hobbyist) PCB manufacturer (oshpark) who has put lots of effort in getting the color of the solder mask just the right hue of violet. It suddenly became his trademarkIn Daves teardown photos you'll also find pointless logos, a striking one is in the Rigol Power Supply:http://www.flickr.com/photos/eevblog/9607795214/#in/set-72157635251122253. Dave himself puts platypuses on his PCBs...Have a look athttp://electronics.stackexchange.com/questions/4333/what-is-the-most-amazing-pcb-artwork-youve-ever-seen- really amazing stuff, despite likely being a horror from an engineering point of viewI keep pondering what one can do with the amazing precision we're able to get with current PCB production methods. I believe that there still is a lot of room to explore that for artistic purposes.Quote from: AndyC_772 on March 24, 2014, 09:23:12 pmYeah, as soon as a budget comes into play things like that become a burden. Yet at least some of my examples above have originated in a corporate setting. I take that as a hint that someone really was enthusiastic about their work.Quote from: AndyC_772 on March 24, 2014, 09:23:12 pmYeah, it is a pity that (a lot of) the tools are so bad in that regard. I have some experience with Eagle and their workaround scripts for importing bitmaps just suck - in the end the DRC throws tons of warnings if you want to have a better resolution...I ended up writing python scripts to generate ulp scripts that then create polygons for the artworks. It is a really painful amount of work and totally unfeasible if you want to sell your design to somene else. The results however are beautiful and very satisfactoryBye,Simon

author: AndyC_772
author_rank: Super Contributor
timestamp: March 25, 2014, 08:46:48 am
content: Interesting stuff, thanks for sharing. It's quite apparent that those examples are almost all 'hobby' boards rather than, let's say 'professional' boards for want of a better word. Maybe that explains why I've not come across them before.Perhaps one reason why boards are so often purely functional, is that design engineers rarely - if ever - get known or credited for their work once a product goes to market.In, for example, the music industry, it's the people who actually create the product who are advertised, promoted, and most strongly associated with it. Often it's down to just one individual band member, who becomes well known and with whom fans most strongly associate. If that person leaves and starts another band or a solo career, the fan base follows that person even if the original band continues to exist.The music publisher, on the other hand, may own the brand and take the lion's share of the revenue, but is otherwise rarely mentioned. You just don't see posters with, say, "EMI" or "Sony Music" as the headline, and the name of the band mentioned somewhere in the small print. The fact that a record is published by a particular label is, more often than not, inconsequential.Compare and contrast with the electronics industry. For years I've designed boards for employers, whose names appear emblazoned across the products they sell. The names of the actual developers don't appear anywhere on the finished product, and even if the product is superbly engineered, and customers love it, it's the employer's brand that gets the kudos.They're understandably protective of this, of course. They'd much rather build their own reputation than send out products with my name on them, and I can't say I blame them. Maybe the world would be a better place for (good!) engineers if it were normal for them to 'sign' their work, so customers could recognise who actually designed a product and could infer quality on that basis. But it hasn't happened.

author: Dave Turner
author_rank: Frequent Contributor
timestamp: March 25, 2014, 10:32:31 pm
content: From a different discipline (Architecture) one philosophy I was taught was that form follows function. Whilst this isn't the be all and end all, it also makes sense with PCB design, particularly where higher frequencies are concerned.Mathematicians talk about the beauty of an equation which expresses a fundamental truth; in a way like the principle of Occam's Razor.In my view this can be extended to PCB design where an efficient design will just look right, particularly when limited to double sided boards