Hi Jean-Paul, Thanks for the information. I have looked at some videos. Are you aware of some guidelines for THT courtyards?
Also, to answer Michal's question about the courtyard of 0204 SMD resistors, IPC-7351 states a nominal courtyard excess of 0.15mm. See here <http://pcbget.ru/Files/Standarts/IPC_7351.pdf>, page 13. The KLC can be amended On Sat, Jan 10, 2015 at 9:13 PM, Jean-Paul Louis <[email protected]> wrote: > I have not followed the discussion very closely as I am away from home > until end of January, but I would like to make a comment as I see that a > lot of people are confused by te concept of courtyard. The confusion is > very understandable as since the advent of SMT, the courtyard is very close > to the size of the component. > To really understand the concept, one must understand how the parts are > placed on a PCB during the assembly process. Most of the SMT devices are > placed using a vacuum nozzle that is much smaller than the part. So the > courtyard is only needed to make sure that you do not place a part on top > of another. When using automated TH placement, the situation is a lot > different as the machine use grippers instead of vacuum nozzles, so you > need a lot more room around a part to avoid interference with the placement > tools. > To understand better, google terms like VCD, Radial Inserter, DIP inserter > as there are a few videos showing these processes. > > Just my $0.02, > Jean-Paul > AC9GH > > > > > On Jan 10, 2015, at 5:41 PM, Carl Poirier <[email protected]> > wrote: > > > > I was also thinking about C), but discussing it is a good idea. > > > > As for the appropriate measurement, let's make sure we all agree. What > about the courtyard clearance being measured from the edge of the > silkscreen to the center of the courtyard line? There should thus be no > overlap. > > > > Also, THT components and connectors can be at 0.5mm clearance. > > > > Any comments? > > > > On Sat, Jan 10, 2015 at 4:18 PM, nnn <[email protected]> wrote: > > The rule 6.6 is not clear for me. > > > > It's clear that for most of smd components the courtyard should be 0.25 > mm from pads. > > What rules aplly when courtyard isn't determined by pads? > > a) should it be 0.25 mm from silkscreen? > > b) should it only enclose silkscreen? > > c) should it be 0.25 mm from package body and then enlarged to enclose > silkscreen (if necessary)? > > I think the c) is best but it's not defined in convention. > > In cases b) and c) courtyard will be very close to silkscreen. Should it > be allowed that centre of courtyard line lay on boundary of silkscreen line > (0.025 overlap)? Courtyard is area limited by the line, so it seems that > the 0.025 mm overlap should be allowed, but it may look bad. > > > > Line width for courtyard (0.05) should be defined in convention. > > > > The same clearance for 0204 SMD resistor and 5 W THT resistor is > probably bad idea, exactly that electrolytic capacitors has bigger > courtyard because of bigger placement tolerances. Is there any reason for > using bigger courtyard for THT electrolytic capacitor than for eg THT > radial chockes? Why connectors should have bigger courtyard than eg > mechanical switches? > > In document: > http://www.dnu.no/arkiv1/The%20CAD%20Library%20of%20the%20Future.pdf > > in chapter 10.3 it's suggested that it's difficult to determine > courtyard for THT. > > > > > > > > W dniu 09.01.2015 o 20:21, John Beard pisze: > > > > On Fri, 2015-01-09 at 17:54 +0100, nnn wrote: > > There is no information about courtyard line width in kicad library > > convention. > > Can it be 0.05 mm as suggested in: > > > http://www.pcblibraries.com/downloads/temp/PCB_Design_Optimization_Starts_in_the_CAD_Library_8685831.pdf > > ? I used 0.05 eg in Housings_SSOP, so you can check if it looks ok. > > Sounds very sensible to me. Since the guy who wrote that is also one of > > the people on the committee that approved IPC-7351, this is presumably > > consistent with that standard. > > > > Can overlaping courtyard with silkscreen be allowed? It may look bad, > > but it's not specified in rule 6.6. > > As the "IPC" way now is to draw the main silk screen lines at the > > maximum material position for alignment verification purposes, and the > > courtyard by definition is outside that, I think it would make sense to > > at least say that all silk should be contained within the courtyard? > > Otherwise it could be obscured by other components. If the silk extends > > up to or outside the courtyard, that may indicate that the courtyard is > > too tight. > > > > Cheers, > > > > John > > > > > > > > > > > > > > -- > > Mailing list: https://launchpad.net/~kicad-lib-committers > > Post to : [email protected] > > Unsubscribe : https://launchpad.net/~kicad-lib-committers > > More help : https://help.launchpad.net/ListHelp > > > > -- > > Mailing list: https://launchpad.net/~kicad-lib-committers > > Post to : [email protected] > > Unsubscribe : https://launchpad.net/~kicad-lib-committers > > More help : https://help.launchpad.net/ListHelp > >
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