The problem is most board houses do not update the Cam tool software
and do not have the latest release of 274X.
Lou
Dave Roesler wrote:
> Gerry,
>
> I don't think that the RS 274X standard is the issue. This standard has
> been around for a long time. Generally, if there is a problem it is due to
> the interpretation of the standard by CAD and CAM system developers. I had
> a lot of experience with this issue because I ran a software development
> group who developed CAM and pre-production analysis software. We also
> owned a number of service bureaus. Therefore, I saw data from any number
> of CAD and CAM systems. As a service bureau we had to be able to read
> whatever was thrown our way regardless whether it matched the standard or
> not. Whenever possible, I would contact individuals who produced
> "incorrect" data to get them to put pressure on their software vendor to
> correct the problem.
>
> I have been involved in many meetings with CAD vendors including IPC
> sponsored events. Generally, the CAD vendors do not put much effort into
> output translators because good output is not viewed as a feature that
> sells more systems. They put their emphasis on routing, placement, etc.
> In more than one meeting I was told, point blank, that output did not get
> much development effort. As a result, many of the RS 274X outputs from the
> CAD systems, though correct per the format spec, are very poor.
>
> This leaves the CAM vendor with the responsibility of trying to read every
> flavor and interpretation of RS 274X. One of the biggest issues is
> polygons. CAM systems attempt to police valid polygons. They are required
> to do this because they must produce photoplotter output and, therefore,
> the polygons must match the requirements of the photoplotter. I would
> venture to guess that most of the polygons that VALOR CAM says are illegal
> would not plot if sent directly to the photoplotter. In this case, the CAM
> software must be robust enough to handle the illegal polygons and make them
> plottable. It is too bad that the CAM systems must compensate, but until
> we can get the CAD vendors to produce good output it is the way it has to
> be.
>
> Dave Roesler
> TRI-C Design, Inc.
>
> ----------
> > From: Gerald G. Gagnon <[log in to unmask]>
> > To: [log in to unmask]
> > Subject: Re: [DC] RS274X format problem
> > Date: Thursday, October 15, 1998 7:20 AM
> >
> > Hi All
> >
> > The recent posts regarding RS274X have been very timely as I have seen a
> > rash of problems with a vendor not being able to read these files into
> > their VALOR CAM system due to "illegal polygon fills". I believe this
> > issue is different than the compositing issues from this thread. Other
> > board shops either do not seem to have the problem or have developed
> > suitable workarounds to keep their jobs going.
> >
> > What concerns me most is whether or not this is an RS274X standard
> > issue, a CAD RS274X translator issue, or a board shop CAM RS274X issue.
> >
> > Any comments?
> >
> > Regards
> >
> > Gerry Gagnon
> >
> > Interconnect Technology
> > AlphaServers Platform Development
> > 129 Parker Street
> > Mail Stop: PKO3-1/20C
> > Maynard, MA 01754-2198
> >
> > ' Phone: (978)493-1210
> > * Fax: (978)493-0941
> > * Email: [log in to unmask]
> >
> >
> >
> >
> >
> >
> > -----Original Message-----
> > From: Hawes, Adam [mailto:[log in to unmask]]
> > Sent: Thursday, October 15, 1998 3:35 AM
> > To: [log in to unmask]
> > Subject: Re: [DC] RS274X format problem
> >
> > Dennis,
> >
> > You're not alone.......
> >
> > Composite layers are when the CAM software uses several layers to create
> > one
> > artwork layer i.e. what exists as one layer in Allegro e.g. your power
> > plane
> > is made up of several layers in the CAM environment. (forgive me if you
> > already knew this!)
> >
> > The fabricator only has a limited number of layers available to play
> > with
> > and we have had a problem with RS274X, especially on boards with several
> > PWR/GND layers, where the fabricator has complained of not having enough
> > layers to complete all the composites.
> >
> > I believe there is a Skill routine on the Cadence Web site that allows
> > you
> > to reduce the number of layers needed for composites. I've never used it
> > so
> > I don't know how reliable it is or if it's any good. Other than that,
> > the
> > only thing I can suggest is that you talk to your fabricator.
> >
> > Hope this helps.
> >
> > Adam Hawes
> >
> > > -----Original Message-----
> > > From: Dennis Ward [SMTP:[log in to unmask]]
> > > Sent: Wednesday, October 14, 1998 12:49 AM
> > > To: [log in to unmask]
> > > Subject: [DC] RS274X format problem
> > >
> > > Hello,
> > >
> > > The fab house I'm using has encountered a problem importing my RS274X
> > > artwork.
> > > I believe their software is having a hard time compositing(?) the
> > power
> > > plane layers.
> > > I'm still unsure what exactly is happening - I plan on visiting them
> > > tomorrow and see
> > > first hand.
> > >
> > > My software (output) - Allegro designer - version 13
> > > Theirs (Input) - Tibor Davos - version unknown.
> > >
> > > Has anyone else experienced any difficulties with RS274X formatted
> > power
> > > and ground planes
> > > generated from Allegro??
> > >
> > > Any (I do mean ANY) help would be appreciated.
> > >
> > > Thanks
> > > Dennis Ward
> > > Net to Net Technologies
> > >
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--
Lou Dallara PCB Design Engineer
"Civilization is a limitless multiplication of unnecessary necessities" -
Mark Twain
http://www.waterwheel.net/~ldallara/
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