Since this is always a issue with all designs I will revisit this thread...
Fonts used for designing then converted to 3D must NOT have-
Small lines, joins or tight angles that will not print!
varying thickness or closely aligned spacing ( small tight gaps will fail checks!)
Small circles or dots in loops and letters like AQDBROP09864 problems with 2 3 E K C and especially "S"!
Small connections, gaps or spacing must be fixed!
There are three kinds of font printing
1) Engraved
2) Embossed
3) Self Supporting
Examples of the first two are most common as the names imply.
With "Engraved" or "etched" the letters are formed by first by removal of material or at SW the lack of printing. these are always "gaps" to SW designs.
Raised text that is above the models surface is "Embossed" but always supported from underneath for all letters. these are "walls"
last is harder to define bu simplly a design that uses letters/fonts as the primary surface and must be self supporting, water tight or have no parts that will "fall off" after printing...these vary greatly...
For each use and each material the best fonts will always vary. No universal constant is true, however some are better than others. If you search for a font try simple, clean or bold lines and fonts keywords. Also in some applications "stencil" is a good search term.
Customization of fonts and tools to create your own do exist...most are not totally free.
http://www.textsketcher.com/
I have found several fonts that work but each depends on the minimum material specifications... Also since we cannot control orientation of our Models (hint/hint) then this is a good tutorial link-
Here are some to try- (see attached)
ERCK Gillis
The BLACK LAB Design
Beta Decay byproducts