On Thu, 02 Dec 2010 15:44:34 -0500 Rick Collins <gnuarm.2...@arius.com> wrote:
> I'm not asking about the pick point. I'm asking about the > centroid. They are completely different things. As I think I said, > the centroid is to tell the assembly house where to put the > part. The pick point is a point on the part where the machine will > attach the nozzle and has nothing to do with the position where the > part is to be placed. Further, regardless of how you set your files, > the pick point is selected by the assembly house to optimize how they > pick the part. You have no way of knowing where this will be. That is good news. > The centroid needs to be a spot on the part that everyone knows > without requiring it to be explained. Unfortunately for oddly shaped > parts, it does not seem to be well understood how to select the > centroid. One document I have from "Screaming Circuits" says it is > the center of the part including the pins and the body. I have yet > to be able to find this info in an IPC document. The IPC document > seems to leave out some other important info about rotations. You > would think they would figure out this is a problem and fix it... > > I can't say if your centroids will give you trouble, but from what > you are telling me, you are not defining them correctly. From what I > have read, I'm not sure PCB does it correctly either. I found some > references on the web that says they use the geometric center of the > pins not including the package. I don't think that is right. > > Screaming circuits is not the ultimate reference for defining how > this is to be done, but they have a document that covers all the > bases and is easy to understand. In fact, when I pointed out that > they had a discrpancy with the IPC docs, they immediately fixed it > and put the updated doc on their web site. www.screamingcircuits.com Okay. Thank you for pointing out all that. I think I'll be fine with the centroids. It states that the centroid must be the center of the entire footprint. It gave me some information about the rotating angle. I go and tweak my script. Thank you again, Levente -- Levente Kovacs http://levente.logonex.eu _______________________________________________ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user