Various gerber formats can be usually exported to STL format (Stereolithrography) for 3D printing. You can use programs like ACE 3000 converter for this, but you can probably find more alternatives for gerber to stl conversion. Sometimes you need to use a specific gerber format, for example gbr.
Convert Printed circuit board photoplotter file to Stereolithography CAD file.
We have found one software suitable in our database for this conversion.
Microsoft Windows software - convert gerber to stl on Windows
A CAD and Gerber conversion software
Convert from gerber file format
The table with program actions contains information about what each program is capable of doing with their files. This may be a good pointer for further searches for certain file conversions and help you find the converter you are looking for if our search result is insufficient for you. However, it is far from perfect and may sometimes show results which are not really usable because of the nature of the software handles the files. So a conversion that appears as possible, just because of matched actions, may in fact not be possible.