0.2 mm sounds OK, but it's only eight thousandths of an inch. Any defect, even a change of hardness/annealing, in the copper creates a stress-concentration point, leading to a crack. I think you should make the tracks as wide as possible, for good reliability.

On 2024-01-11 16:01, Robert via groups.io wrote:

The lines concerned are I2C clock and data, and yes, I will be
considering them as transmission lines. However, there's no point
laying something down that is electrically just fine if the board cannot
be manufactured reliably or the tracks break during assembly (it will
get bolted down, but before that happens someone will have to pick it up
and move it into position).

Chinese PCB houses can routinely achieve 0.15 mm on normal sized boards.
So am I worrying about nothing, because they will in fact have no
trouble with a track (say) 0.2 mm wide and 500 mm long, if that's what I
would choose from an electrical viewpoint?

Regards,

Robert.

* Plain text email - safe, readable, inclusive. *

The lines concerned are I2C clock and data, and yes, I will be
considering them as transmission lines.?? However, there's no point
laying something down that is electrically just fine if the board cannot
be manufactured reliably or the tracks break during assembly (it will
get bolted down, but before that happens someone will have to pick it up
and move it into position).

Chinese PCB houses can routinely achieve 0.15 mm on normal sized boards.
? So am I worrying about nothing, because they will in fact have no
trouble with a track (say) 0.2 mm wide and 500 mm long, if that's what I
would choose from an electrical viewpoint?

Regards,

Robert.

* Plain text email - safe, readable, inclusive. *

Hi,
Does anyone know of any guidance as to how wide very long straight
tracks should be to avoid manufacturing difficulties or breakage due to
board flexing (or any other potential problem I haven't thought of)??? I
have to run a couple of signal tracks a distance of 500 mm and I'm
guessing that my usual 0.2 mm width would be a bad idea, but I don't
want to make them excessively wide as that would add unwanted capacitance.
Regards,
Robert
* Plain text email - safe, readable, inclusive. *

I wish you could use sheets, but the best I've been able to do is make up a bogus "root" sheet that's never used and then you can have sheets under it.? Messy, but works.

On 29-Nov-23 17:39, John Woodgate wrote:

Is is possible to add a second schematic sheet, not a hierarchical sheet, to a project?? I use KiCad to draw schematics for diagrams in reports, and this particular project requires two quite large schematics that each take up a whole page. I suppose I could just open a new project, but if I can keep all the stuff together in one project, it would be better.

Hi,
I have been a user for about a year here: I have successfully done quite
a few schematics/PCBs with KiCAD r7.0.5, and love it!? However I failed
to learn how to properly organize my libraries upfront and now I get
error messages frequently when searching for parts.
With that being said and taking full blame for my predicament:? If I
uninstall and do a reinstall with r7.0.9 will it prompt me for library
construction so I can start anew with proper organization, or will it
find settings in my registry and recreate or just pile-on the mess?

Thanks for your pity and assistance.
Howie

Yes,

very VERY sad how the opinion of an engineer is worth so little. Not like we make the thing work in the first place or anything!!

Mentioning "fun" customers/managers...

There's the ones that change your BOM to make it cheaper, use regular
suppliers, or who knows why.

I designed some medical equipment which, of course, use high quality
precision parts.? Without telling me, they ordered the boards with
substitute parts.? $5 op-amps were replaced with $0.49 ones, connectors
with locking housings were replaced by non-locking ones they could get
from the local electronics hobby store, and so on.

First test on a patient (hey, maybe the engineer should look at it
first!) gave the patient a shock and apparently they saw a trippy light
show.

Next they found the cables fell off in use.? Gee, if I'd only specified
locking connectors.? Oh, right, I did.? They solved it with large blobs
of hot melt glue.

Then they decided to sell these in Japan and a company official flew
over there with a unit for approval testing.? When they did the
isolation tests, the unit went up in smoke.

Seems Japan has higher test voltages than the USA for this gear, and
nobody told me they were going to Japan.

Hardly ever 'breadboard' anything either.

Not to mention the quality of a circuit build on a PCB. Ground loops, stray capacitance, reduced inductance, etc.

For a large projects with a bunch of 'building blocks', it's quick enough to make new 'blocks' on a small board to allow separate testing. Low cost PCB's allow finding issues before the whole system is integrated. On a board with 1000+ part BOM, this can be a lifesaver.

The prices are ridiculously low even when you include shipping. The time it takes means I rarely breadboard on veroboard anymore and just design straight in Kicad then to pcb.
I remember in the UK when you got charged per drilled hole for pcb?s so after laying out the board I used to spend ages reducing the number of vias to get the cost down.
I still do that as a challenge but not as much as before..