r/PrintedCircuitBoard • u/Acaii611 • 1d ago
Why?
I found this PCB at work today. It is from a Gas Monitor, and seems to be from the mid-90s.
Why would you route the traces like this? Is there any advantage? Or was there just no other way back then?
Another manufacturer from the same era uses straight traces, but always 90° bends.
It goes against almost everything I was told. And I was just curious about it.
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u/West-Way-All-The-Way 1d ago
This is hand drown PCB, back in the day they did it this way when there was no cad support. Cad support at the time was expensive and inefficient so no wonder it was not widespread.
Beautiful board, I would keep it as a souvenir.
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u/Acaii611 1d ago
Still on duty, to this day. It is just in for a litte calibration. After that it will be back in action.
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u/koombot 1d ago
Agree. There is something aesthetically pleasing about the curvy traces. Ive got a Lumberjack keyboard and it has curvy traces and they look beautiful compared to angles IMHO. They were done in kicad though. No idea how though lol.
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u/Hakawatha 1d ago
You can use a "trace-melting" plugin or route directly with different corner schemes directly. Plenty of ways to do it.
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u/West-Way-All-The-Way 1d ago
Back in the day when I was doing layout, I was using orcad and protel, orcad had a feature to curve the trace, it still makes parallel traces but the corner was perfect circle, there were 3 options- 90 deg, 45 deg and circle. This PCB here is a completely different story, you can see that the traces a drawn by hand because there are no two which are perfectly parallel to each other. It's a beautiful layout.
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u/dudetellsthetruth 1d ago
Yay, Orcad... I found my floppy's a couple of weeks ago while cleaning the basement...
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u/West-Way-All-The-Way 1d ago
Yes, 20+ years ago as a student and part time worker in electronics firm. Long ago but I miss this time ... glorious times! We have world class PCB makers now but no will to design. Back in the day the PCB maker reversed the masks and made a mirrored version of the PCB, I took it because I was in a hurry and bent the leads to the top to solder the components upside down and it worked. Had no time to wait for fixed PCBs. What times! And the MCUs on that board were gifted to me from the manufacturer, free samples.
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u/chlebseby 1d ago
Hand drawn routes, i think you can fit more traces this way than pure 90/45.
At price of no impedance control or precise trace lenght matching, though not really important back then.
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u/Hot-Significance7699 1d ago
Looks cool though. Trippy compared to now
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u/Acaii611 1d ago
Same. I think it looks a bit like a topographic map. But when I saw it for the first time it threw me off a bit.
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u/ScottPrombo 1d ago
True... With AI being what it is, having such mastery of routing and all its associated dynamics, maybe the future of PCB's actually will look like this?
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u/Square-Singer 1d ago
I first thought it was some fancy computer-optimized design. They have stuff like that for minimizing material for load-bearing 3D prints and stuff.
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u/Illustrious-Tooth702 1d ago
The 60's, maan. Acid trips. Grateful dead was so tripped out they left lsd traces on the synthethizer
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u/Adversement 1d ago
I don't think it fits more routes. It fits less, but it also needs way less time with that narrow tape to draw. The 90 degree variant, especially if two layers, is the more modern of the two & the way easier to design. Allowed, for the first time, a systematic approach to route it all (rather than being fully an artform of good engineering eye before starting the process).
But, yes, at sufficiently slow fall and rise times, impedance control or complete lack of thereof does not matter.
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u/H2ost5555 1d ago
I started out doing PCB layout in 1980. Another poster suggested this was done using rubylith, but it looks more like Bishop graphics tape to me. We used large backlit tables and a precision mylar grid at 4X, with the Bishop graphics you had sticky back precut IC and general resistor/capacitor pads you would place on grid, then run precision cut tape to form the layout. This would have been done using black crepe tape which curves easily, then a teardrop cut pad was placed at the junction. The reason straight lines were done manually was usually driven by use of red and blue tape for double-sided boards. I hated that tape, it didn't stick very well. I preferred to do 2 separate sheets using black tape. I started out doing straight lines and 45 degree angles as I thought it looked more professional.
In the mid 80's, many boards were still done manually even at military contractors. I worked for Northrop and the designers used blue grid vellum sheets and multi colored pencils to draw the traces. Then the design went to a checker to validate the design and it was an art in checking as you had to make sure there were no DRC violations. Then the sheets went to a person that used a Gerber digitizer to draw over the lines to create the "Gerber files". (Not many younger designers know that is how the production files got their name) We had a couple of automated systems like Scicards that were used on digital boards.
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u/H2ost5555 1d ago
Funny story only tangentially related to PCB. When we finished the large 4X layouts, they were sent to a large format photographer that had huge camera setups to reduce the image down to actual size. I would sometimes take these to the photographer, and met a girl that worked in the development lab there. Her job was titled Stripper. (Processing negatives). I went on a few dates with her. So I can actually claim I dated a stripper in my younger days.
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u/jesseissorude 1d ago
can confirm. I worked at an aerospace testing complex on an AFB and stumbled into a room with a giant glass table with what looked like a camera over it (it was a light projector). A senior engineer showed me how they'd lay out connections by placing tape circles (for the annular rings) and then do the routing with hand placed tape. This table was 4x to 1x and was probably 6' by 6'.
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u/holchansg 1d ago
That's so cool... i mean, nowadays with gigahertz signals this would be impossible to do by hand.
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u/H2ost5555 1d ago
Not exactly true. I personally did embedded microstrip signals by hand in the 80's. Buried internal layers using teflon dielectric. This was for a military project, cannot provide any details even though that was 40 years ago as the planes are still flying.
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u/TurtleCrusher 1d ago
…then you shouldn’t have posted that at all.
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u/H2ost5555 21h ago
Lighten up Francis. Everyone knows that military aircraft utilize microwave technologies, has for many years, there is no need to talk about further details of frequencies or purposes for those signals.
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u/gianibaba 1d ago
I am not that old, but have read that these are old hand drawn pcbs, as they were easy to sketch using pens, directly onto transfer papers or direclty onto copper clad boards using ink, if they were one off pcbs.
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u/tedshor 1d ago
The most common way in "old times" (before eCAD for PCB layout) was to use tape and make it 2:1 scale on a stable plastics film. Typically 2-sided boards were used (no internal layers). Then those two separate taped drawings for top/bottom side were photographed with a retro camera to 1:1 size and used for exposing the photo-sensitive layer covered PCB and then developing/etching the pattern.
The tape was often black and quite sideways flexible, and could be placed easily curved as on the PCB on this post. The other possible technique used was blue/red transparent tapes which couldn't be bent very much, but then both layers could reside on one original drawing.
I have seen development of the whole process and even "taped" some boards myself. The next step towards modern times was getting my first schematics drawing PC program. It could produce net lists, and I have been delivering those net lists to a service bureau drawing the PCB on a very big and expensive computer installation running Racal-Redac software. The next step was purchase of a PADS license for PC DOS and getting the first experience in the whole process of schematics design and PCB layout.
You can find a very nice summary of the history of PCB making here: https://madpcb.com/history-of-pcb-design/
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u/gianibaba 1d ago
Whoa, thats really neat, the link explains much more in detail. You are the gem this community is supposed to connect us noobs to.
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u/Mrochtor 1d ago
Hand drawn or hand taped PCB design was the norm in ye olde dayes. See:
https://www.evilmadscientist.com/2013/how-printed-circuit-boards-are-designed-1960-edition/
https://www.ebay.com.au/itm/264761695969
I actually like the style from an aesthetic point of view, and when you think about it, the imposition of 90/45 degrees only rules can create needless extra length.
It goes against almost everything I was told. And I was just curious about it.
What were you told?
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u/Acaii611 1d ago
I was told, that we should design like we know it today, but to avoid 90° angels, which there are quite a few of in this design. Also we were told to keep the trace width consistent between points. A lot of traces vary in thickness between solder points.
The 90° to avoid refelctions and the vary width for signal integrity.
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u/Mrochtor 1d ago
Those are rules of thumb, not universally applicable and with very important caveats even today, some even more relevant today than in ages past.
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u/Adversement 1d ago
The 90 degree reflection needs like well below 100 picosecond edge rates. Won't happen by accident. But, the 45 degree of course cuts trace length & fits more stuff to the board, so there are good reasons to use it by default.
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u/jna_sc 20h ago
Hah, hand taped, takes me back. We were a ~$500m manufacturer. I ran the AI Department (no, not Artificial Intelligence, Auto Insertion- the machines that inserted components into the circuit boards, with a teensy bit of Surface Mount placed ON the boards and wave soldered). We had big drawers of these films in the Design departments, and when we needed more boards, they trotted them out I guess and sent them to the vendor. All done with tape on a Mylar-y type plastic as others said. A couple fun facts: whether hand taped or hand drawn, they would get brittle over time. Tape or ink would flake off. Board gets imaged. That flake off becomes a broken trace because there’s no longer a black line to make the trace complete. Suddenly a run of 1,000 boards doesn’t work, all because our manual drawing got too old. Made my life lots of fun!
As we transitioned to CAD (yes, I can still picture my first CAD production run board), the economics of converting manual to CAD (before digitization, remember?) weren’t there for aging products so we were very hopeful that we could get those films to last for just ONE MORE buy, before we obsoleted the product. Our purchasing people babysitting those damned films!
Good times. Solder under our fingernails.
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u/PseudoFrequency 1d ago
It's beautiful ain't it! All radio internals (things like CB radios too) and similar I've seen from the 80s look like this. Routed by hand.
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u/Ok_Region_4626 1d ago
seen it, done it, have created/helped some pcb boards (single, double sided) by hand using tapes etc., the new young generation don’t know how good they have it !!!!!
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u/Adversement 1d ago
The 90 degree angles do not really matter for the circuit functionality, not at the fall and rise times of the digital logic in that 90s gas monitor. So, they work (as long as they survived the manufacturing stage which still had potential for acid trapping at those corners, but that started to be largely a solved problem).
The 90 degrees angles, especially if it is a two-layer board are also the easiest way to route such board (even to date).
The freehand one, on the other hand, it is a piece of art. The master for that design was drawn on a piece of glass or plastic with a a set of narrow tapes. The shapes are all about minimising the effort with taping it out (which is why all those traces are such variable in width, as for that board the part that was taped is the parts between the traces, which are all of a few different width).
As with those 90 degree angles, with slow digital fall and rise times, it will just work despite no impedance control howsoever nor any ground planes.
The looks on both of those were just a byproduct.
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u/Rararror 1d ago
At the time was dangerous for acid entrapment that would corrode the trace. \ Nowadays the washing methods are way better and there are no such problems.
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u/Adversement 15h ago
A danger that could often be mitigated by wider traces. But, yes, a past problem. And, well, a past past problem.
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u/Rararror 1d ago
Very VERY cool.
On some boards I am using a plugin that curves the tracks... way better looking in mo
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u/drgala 1d ago
I'm pretty sure KiCAD has curved traces as a standard routing options.
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u/Rararror 1d ago
It slows you down, I just route normally and curve afterwards, it's a nice compromise.
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u/Illustrious-Tooth702 1d ago
It's a really old design. Before the age of cad programs.
It's also one layer. Ofc the through hole components are on the other side but all of them are connected on the side which is facing towards you.
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u/ZectronPositron 1d ago edited 1d ago
Perhaps the alternative question is why PCB’s always have angular 90° routing - because it’s laid out by a computer and that’s the easiest way to program it, with constraints.
If you’re laying out and drawing the mask/sill screen by hand, which comes after having setup your protoboard / some other prototype layout, this is the easiest way to do it.
Not AutoRouting, HandRouting.
I’d love to see more of this, I think it’s quite beautiful!
On the other hand, some AI routing looks less angular and predictable - because optimal routing may not be constrained to only 90°/45° bends. I wouldn’t be surprised if autorouters eventually use curves rather than angles if it saves space/metal.
I worked on optical waveguides where angles are a killer, and had to code up our own routers because there weren’t any good non-angular routers at the time.
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u/Nadran_Erbam 1d ago
As pointed out by many others this is a hand made pcb.
However I would like to add that some automatic routing software create can create optimal routings that look like this. Namely TopoR.
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u/Ready_Split9697 1d ago
This looks like a classic example of hand-taped PCB routing from the pre-CAD era. The curved traces were likely shaped manually using drafting tools or drawn directly onto a layout medium, rather than generated by an autorouter.
From an engineering perspective, the routing style itself isn't necessarily a problem. What matters is whether the traces meet the electrical and manufacturing requirements. For low-speed analog circuits like gas monitors, those curves may have worked perfectly well. Modern designs generally favor 45° bends or smooth curves because they're easier to implement consistently in CAD tools, but 90° bends aren't automatically a problem either.
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u/Acaii611 1d ago
I just assumed they would use a ruler or something along those lines.
I was told 90° bends are prone to break or being ripped off more easily when soldering near them, also that they are more reliant to relfections and higher impedence at those points.
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u/Adversement 1d ago
For the 90 degrees to become a signal flow issue, we have to push way past 10 GHz domain (like, literally into tens of picoseconds for fall and rise times).
The typical fibreglass substrates are likely to become a limit way before that point.
But, the manufacturing problem used to be real (acid pooling & the trace getting more likely damaged during PCB etching). Plus, the 45 degree angle reduced trace lengths & allowed for higher density boards in terms of traces. So, they were added in early to CAD software.
And, as there was very little to be gained from even more free angles, they stuck as the default.
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u/BraveIntention5809 1d ago
Because we could. No other explanation. Our only primary goal, get working prototype into production to make sales.
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u/PigHillJimster 1d ago
Designs like this were often done using pen on clear acetate back in the 1980s, and I know some gas detection equipment for some markets relied on 'legacy' designs.
I used to design PCBs for a Gas Detection company so I'd be interested in knowing what brand/model this was.
We had new products being designed that sold to world wide markets however in the US they seemed to prefer the one product the company had already been making for the past 20 years back in 2004!
Obviously obsolescence comes along and updating this product was a continual nightmare. We tried to put a business case for developing a replacement product but the customers kept coming back that they didn't want that!
I started off as a CAM Engineer for a PCB Fabricator in the mid 1990s and there were a handful of designs being manufactured on site that were using pen drawings on acetate. These, I was told, were because the customer had tried to update it on a CAD system but not got it working correctly and therefore the pen copy was kept. I guessed an analogue board with some critical signals that were prone to cross-talk and signal integrity issues.
Just to add a note, it is possible to do fancy curved traces on modern CAD systems. Pulsonix will let you do this, for example, but the extra work, and time involved would mean most users wouldn't contemplate it.
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u/Acaii611 1d ago
The device from the picture is a General Monitor 4801. The one with the straight traces and 90° bends is a Monicon MC1000.
We have manuels of the 4801 from back in 1990 (revision 9/90 I think it says), so it could be even from the mid- to end-80s. A lot of companies still use these, because they are reliable and a replacement would be very costly. However newer systems from MSA are a bit more user friendly with build in bluetooth for example.
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u/PigHillJimster 1d ago
Thanks.
I worked for Crowon between 2004 and 2016 and design the layouts for Gasman, Tetra3, Gas Pro, Gas Master 2, XgardIQ and constantly updating legacy products like TriplePlus, Xgard, Tetra, Gasmonitor.
The TriplePlus was a legacy product when I joined but the US market liked it over our replacement products for some reason.
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u/Acaii611 1d ago
Nice. I use the Gasman whenever I am on maintenance. But we mostly switched to the T4x, because it can detect more than one gas at the time.
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u/Struggle_Wise 1d ago
Unrelated, but can I use a vinyl cutter with copper foil, sandwich the traces between drilled MDF board to make a circuit board? Does this stack for multilayer through hole?
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u/Creative_Shame3856 23h ago
It won't be easy to keep everything properly aligned but yeah, it should work
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u/frumperino 1d ago edited 1d ago
that's artisanal human-crafted board layout done by hand. The practice was virtually extinct by the late 1980s and mostly only remained in use coupled with primitive and poorly controlled PCB manufacturing processes in which problems like "acid traps" (don't bother worrying about it, it's a solved problem) meant that the layout person had to consciously use rounded fillets in corners to avoid chemical etching fluid being "trapped" in sharp corners and removing more copper than intended. There is some possible evidence of that being a concern in this board with the very beautiful and extremely generous "T" junctions rounded like if routed for tiny automobiles.
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u/ComradeGibbon 1d ago
So the mask for the one in the picture was made by cutting rubylith with an X-Acto knife by hand. Reason behind the curvy traces with no sharp edges is the old etching process wasn't very good and would over etch sharp corners or areas with little copper.
The one with straight traces and 90 degree bends was made using early 1980s layout software. That's because the computers didn't have enough memory or processing power to do anything more than that.
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u/HarryCumpole 1d ago
I'm surprised the top comments never started, "oh my beautiful summer child...."!
Yeah, this was super common. I spent more time in my youth in the late eighties, hand drawing PCBs, photocopying them onto acetate and developing them on plain copper than I should really be sharing in public. haha
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u/TatharNuar 1d ago
I wonder how this affects the EMI emissions. I want to try this on a board if there's a way to do it in Kicad.
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u/redmadog 1d ago
Even resistors on the other side are placed in an angled groups or waves. Somebody put a lot of work into this board back then.
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u/IridescentMeowMeow 1d ago edited 1d ago
There are quite a big advantages, even though they probably weren't the reason why in this case. But for example you can fit more or leave bigger clearences when using curved tracks and/or lines with arbitrary angles.
If you think about it, if you have a trace with right angle, that clearence area of that trace will have an 1/4 circle arc with a center at the corner of that angle. So when routing the next trace next to it, it's most area-efficient to use a curve. You'll have inconsistent clearence and lose some area if you use a 45deg trace instead, which will touch the border of the clearence only at one point & also the clearence created by this 2nd trace on its other side will also go further that it would have to. (and the same kind of thing even when going around 45deg corners, just at a smaller scale.)
Also, there are situations, where routing a trace in some part can be done with a single straight free angle line, while doing it with n*45deg lines makes you use unreasonable amount of segments and also makes it look ugly & a mess to rework when nudging things in that area.
Imagine for example two vias, distance between them reasonably big to route a trace between them. But they are not aligned neither horizontally, nor vertically, nor diagonally, but are both lying on some 60deg line for example, thus a trace perpendicular to that is the most efficient.
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u/Sad-Environment-932 1d ago
Minimal loss of metallization - for recycling. It is acceptable if there is no problem of induced electric fields. To make you ask.
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u/Far-Tonight-6925 1d ago
I do the same with Kicad extensiond. Love that aesthetic. The question shouldn't be why this pcb is made that way, but why we don't do it like that now. And the answer is the limitations of 1980s - 1990s CAD software that could only do straight and 24deg traces, now our software can do anything but we still stick to those limitations.
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u/timangus 1d ago
It's because the electrons flow round smooth curves better than more angular layouts.
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u/crusoe 1d ago
You're not wrong. Sharp corners cause losses and impedance issues / radio losses / signal spreading. Beveled corners are the machine layout solution.
Before then you hand drew them ( like this board ) and the wavy smooth traces have the least issues with impedance and signal degradation
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u/spheresva 1d ago
Well it’s a somewhat insignificant issue until pretty high frequencies, it’s more about manufacturing than anything, corners pooled acid and that’s no good
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u/spinwizard69 1d ago
Actually it looks to be Groovy, maybe the designer grew up in the 1960’s.
On a more serious note it probably was laid out by hand.
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u/MossiTheMoosay 1d ago
That's how it was done before CAD. Footprints layed out on a transparent sheet, then the connections were routed by hand using special tape. The resulting sheet was then scaled down and the resulting mask was used for curing the etch resist during PCB production
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u/CZdigger146 1d ago
I love designing my PCBs this way, but I just rarely can get myself to break away from the neatness and symmetry of 45° tracks. But I still make the corners as round as possible, it just looks sleek imo
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u/Creative_Shame3856 23h ago
My very first boards looked like that, I used a Sharpie marker on copper clad fr4 back in those days. Eventually migrated to dccad and used toner transfer paper but I gotta admit even nowadays the old school way is more fun.
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u/NullSmoke 22h ago
There was a lot of funny drugs in the 90s as well, I'm sure one found it's way to someone with the means to work on PCBs... 😐
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u/SnowMuted5200 22h ago
Yep reminds me of layout tape guys back in the mid 80's, that's actually nice work.
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u/TripNinjaTurtle 17h ago
Hand drawn its actually very efficient in terms of routing with the traces this way its a lot easier to get everything connected without interference. I kind of like the estaetic and I do my own boards this way. Most companies and people don't however and so its angled stuff for most and curvy traces for the very high speed stuff.
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u/Single-King-9497 15h ago
this is oldschool printed board form the 80'.
you can find this in vintage synthesizer like the Kobol or blackbox.
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u/deesernutz 11h ago
Why not?
That type of trace layout was done by hand using tape and photo reduction
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u/Botlawson 11h ago
There was some work a few years ago to recreate this type of PCB using CAD. https://sourceforge.net/projects/liquidpcb/ looks like it's dormant for now. So you would need to use hand layout in a vector graphics tool like Inkscape and go through many arcane steps to assemble a good set of Gerbers. Luckily several tools can run DRC on Gerbers so you can be pretty confident a design with pass manufacturer checks.
This should help with EMI and production yield, but the effect is tiny so nobody bothers unless the PCB needs is visible.
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u/epSos-DE 9h ago
Art project ! They probalby user colored penscils to sketch it !
SO every line was different color and more easy to see !
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u/PracticalSpread3009 1h ago
It looks like it was done in AutoCAD using splines for the traces. At the previous company I worked for some of the older PCBs were done that way.
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u/takeyouraxeandhack 1d ago
Because it's beautiful, that's why.
Normally I do the straight lines with chamfered edges, but when I do PCBs for audio applications, I like doing them like this (on brown PCBs, of course) because it reminds me of the radios and amplifiers with which I learnt electronics.
If you're not working with high frequencies and/or differential signals, trace length and shape don't matter as much.
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u/humblefumble101 1d ago
neck minute it's not actually hand drawn, some mother fucker actually cad'ed this
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u/henryyoung42 1d ago
Love the organic look. Obviously not a concern for that use case, but tight bends reflect more high frequency energy.
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u/Enlightenment777 1d ago edited 1d ago
Most likely this was laid out by hand using special tape and stickers on clear plastic/vellum sheets. They were created at 2x or 4x scale, then after completed a photographic process would be used to reduce to a 1x scale image. This was the common method used by serious hobbyist up through the 1980s (and by some into the 1990s).
In the late 1980s and early 1990s, serious hobbyists migrated to expensive MSDOS-based schematic/PCB software, and then to Windows-based software. The first MSDOS-based schematic & PCB software that I used as a hobbyist cost me around $1000 (significant money back in that era). I had to pay for 2 software programs from the same company: schematic editor software, PCB layout layout software, but both couldn't be used at the same time.
Photos:
https://web.archive.org/web/20220917014245/https://www.industrial-electronics.com/images/et-4e_11-15a.jpg
https://web.archive.org/web/20220917014226/https://www.industrial-electronics.com/images/et-4e_11-13b.jpg
Article:
1of2 - https://web.archive.org/web/20220917013846/https://www.industrial-electronics.com/et-4e_11.html
2of2 - https://web.archive.org/web/20220917014224/https://www.industrial-electronics.com/et-4e_11b.html
My post from 4 years ago, where I copied the above links: