Using EAGLE 6.2.0
I would like to use “Proportional” fonts for my silkscreen layers (21 tPlace, 22 bPlace, 25 tNames 26 bNames, 27 tValues and 28 bValues). Size = 40mil, Ratio = 12% and Font = Proportional.
Can your service process these font types on these layers without making changes to the way they are displayed on the PCB? I will be using your Fusion DRU and CAM files for EAGLE.
I use “Vector” fonts for all copper layers.
What values do you generally recommend for the text properties “Size”, “Ratio” and “Font” on a medium component density board?
Well silly me. I guess I’ve answered my own question. Assuming the board is reproduced exactly like the Gerber files that are provided to the board house, then one would think it would be those files that determine how the silkscreen will look.
To see what the text would look like after the Gerbers were created with different properties applied, I did the following.
First, I entered the text below into the tNames layer on a “test” board file.
I entered each line three times giving the first of each line the properties of Size = 40mil, Ratio = 12% and Font = Proportional, the second of each line the properties of Size = 40mil, Ratio = 12% and Font = Vector and the third of each line the properties of Size = 40mil, Ratio = 18% and Font = Vector.
Using the “Seeed_Gerber_Generater_v0r95_DrillAlign” file found here http://www.seeedstudio.com/depot/datasheet/Fusion%20eagle.zip, I created the Gerber files.
Using Gerberlogix V2.7 to review the Gerber files, I noticed that the 12% ratio Proportional fonts looked the same as the 12% Vector fonts. Either EAGLE or Gerberlogix had changed the Proportional font to a vector based font.
Next, I printed the .GTO layer (the layer with the fonts) from Gerberlogix with a 1:1 scale and printer resolution of 600 x 1200 DPI just to see how fonts compared. I found the Size = 40mil, Ratio = 12% and Font = Vector to be the most legible and will be my choice for the first prototype run I do with SeeedStudio.
None of this is meant to tell you what font properties you should use but rather to explain how I’ve come to my decision.