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RS-274-D Gerber file - Thermal Apertures

The problem seems to be limited to the thermal apertures that are located on the negative plane layers PGP0310 & PGP0410. I’ve attached the current workplace file as well as the original RS-274-D Gerber files for the two plane layers. From the *.REP file I can see where the OD of the thermal is specified, but that is the only parameter that is specified so I’m not sure how ID or other specifications (i.e. gap width) are being determined when the apertures are imported. Based on what you said about the ODB++ guidelines, it sounds like the angle and number of spokes is set so it’s only the ID and gap width that needs to be corrected. Maybe the *.PHO files contain the required information but I’m not sure.
I think the reason that the apertures weren’t getting updated when I changed the ID and OD is because the number of spokes was 0 and the gap width was 0, which generated an error that the gap width can’t be zero. I just check this and that was definitely the problem so I can update the exiting thermal apertures as long as I know the correct parameters to use.
So the only issue is that when I imported the apertures it didn’t determine the Gap Width, Spoke Count, Open Ends, and potentially the ID for the thermal apertures correctly. The snap shot I send you from the Gerber viewer shows Thermal Lines, but I think the correct shape is just Thermal (circular).
Let me know what you find out from the RS-274-D Gerber files.

1 Comment

1.  Are these your files generated from a CAD tool?  If yes, I would strongly encourage you to re-export the Gerbers as 274X and everything will be fine.   However if this is customer generated data than we can proceed by updating the Apertures.

Note:  The old Gerber 274D format (from the 1980's and before) is obsolete and deprecated, plus strongly discouraged by the PCB industry - due to potential operator errors and misinterpretation. For example, the aperture list just states THER (without any further parameters -- # of spokes, width of spokes, etc.).  I do not believe the Thermal should be 4 lines as shown in the Gerber viewer.   IT should have the following appearance.

2.  A generic Thermal will have 4 spokes (at 45 degree angles) and the spoke gap width will be equal to 1/2 (OD-ID).

Here's a tutorial how to perform edits on FAB 3000 to add Thermal:

Note:  We have updated FAB 3000 to automatically add 4 Spokes and assign the Gap for 274D Thermals when no parameters are available.  This will allow you to easily import all 274D files and get the desired thermals your require.

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