Stats

  • Locked Locked
  • Replies 12
  • Subscribers 167
  • Views 18328
  • Members are here 0
More Content
This discussion has been locked.
You can no longer post new replies to this discussion. If you have a question you can start a new discussion

Two Layer Board with copper fill on top and bottom; Problems with Void touching Shape

NelsonsTrfgr

Allegro 16.3. I have created a simple two layer board with copper fill on top and bottom. This copper fill is my ground plane. I followed a manual that explained how to create the shape, assign a net name and create voids. Everything seems ok, I have several SMT footprints and through hole parts and several vias installed on the board. When I do the update DRC, it returns with no DRC errors detected. When I go to produce the artwork, I choose RS274x, select all films and create artwork. It returns an error:

 ERROR: aborting film - Shape with first seg=(841.447 1910.321) [layer=TOP]
 has a void with extents [(1771.492 748.691) (2223.750 978.392)] that touches
 another shape with first seg=(25.000 25.000). Manually resolve problem.

I followed several of the posts on this forum to attempt to resolve this issue. I moved the entire ground fill (on the top only) away from all other components. This solved the problem. I can get the artwork with no errors. When I try to pin point the offending part, it seems every part on the board will cause the error above. I selected the "Global Dynamic Shape Parameters" menu and set the minimum aperture for gap to 500 mils, along with teh suppress shapes less than 500 mils. This solves the problem, I can get the artwork with no errors. However, my ground plane has shrunk from a 2 inch x 2 inch plane to about 1/8 inch by 1/8 inch in the lower right corner (this is not acceptable). The bottom ground fill does not have these problems. It also has no SMT parts on the bottom.

I know this must be a rookie mistake. But, I followed most of the fixes that were suggested on this forum and nothing works. I also tried to merge Shapes, but this does nothing. What am I doing wrong?

Thanks, Richard

  • redwire
    It's very common for "film" layers to be used as a quick way to set up different visibility during routing.  These layers are not necessarily candidates for Gerber output.  This is what appears to be the case for your board...and I support that method as it has been the way Allegro was initially designed to be used.  So I think if you choose the correct layers in the Artwork output window you will get an error-free result.   Post back up if you have more questions.  Happy routing!!
  • NelsonsTrfgr

    Hi Redwire,

    I have come across another problem. I added two internal plane layers to my *.brd design. One is labeled GROUND_1 the other is GROUND_2. I followed the directions to add Shape->Rectangular and selected the correct layer in the Options tab Etch/GROUND_1. Set the 'Shape Fill' to Dynamic copper. Then added the shape. I selected 'Assign a net name' to my GND net. After that was complete for both ground planes, I verified in the Visibility tab that the layers were there. The problem is no artwork is created for the ground planes. I go to Manufacture->Artwork and select the correct parameters. In the available films window, neither of the ground planes show up to be created. Is it possible I have a setting incorrectly enabled?

     Thanks, Richard

     

  • stump1019

    You have to add the two ground layers to your fim files. Have you done that? For these film files you also need to determine whether you added your planes as a negative or a positive in the cross section, that also needs to be reflected in the film file.

  • redwire

     Like stump says...you need to set up the artwork to generate the layers.   Take a few minutes to peruse the artwork output tab and right mouse on some of the existing layers and see what is there...try right clicking on a folder and add->new; you can exit out of artwork and set up the layer you want to generate artwork from and go back in to Manufacture->artwork and right click on the folder, "match display" and you're pretty much done.  You'll need to decide if you want to turn the planes positive or negative and choose a few more options and then generate.

  • NelsonsTrfgr

    Thanks, Stump/Redwire.

     I think I have the gerbers complete. I have zipped them up and attached them. Would either of you have a moment to look over them and let me know what mistakes need to be corrected before I send these files out to be fabricated?

     Many thanks, Richard

     

    ept_3000_tw_u1a.zip
Cadence Guidelines

Community Guidelines

The Cadence Design Communities support Cadence users and technologists interacting to exchange ideas, news, technical information, and best practices to solve problems and get the most from Cadence technology. The community is open to everyone, and to provide the most value, we require participants to follow our Community Guidelines that facilitate a quality exchange of ideas and information. By accessing, contributing, using or downloading any materials from the site, you agree to be bound by the full Community Guidelines.