In this week’s tip, we look at best practices for designing text on parts, and answer questions like raised or recessed, which fonts to use and alternative options.
Raised or Recessed?
Features can either be raised up or recessed in to part surfaces, but which way is best? Because molds are machined, we prefer to mill the actual text or logo instead of milling around those features. This allows for faster machining, easier polishing and eliminates very small mold features that may break off.
Please extrude the text/logo features by a minimum of 0.010 in. and a maximum of 0.020 in. This allows your text to be legible and not stick in the features while molding — any deeper and you risk having the text peel off and remain in the mold. So, design raised features on your CAD model to improve moldability during manufacturing and legibility on final parts.
If you must have recessed features on your part, many of the same guidelines still exist, but there is one additional concern that you will need to address in regards to the spacing between characters. Having text recessed on your part now means that the features in the mold are raised and we need to machine between each character. Features with less than 0.125 in. of clearance require spacing between each character at a minimum of 0.020 in. to properly remove all material to ensure the legibility of text.
Font Size and Type
The next question to tackle is how wide or narrow your features can be? Again, due to the fact that CNC machining uses ball and flat end-mills, a few important details should be followed during part design. The diameter of end-mills that can produce the majority of part features that have less than 0.125 in. of clearance and can create features no less than 0.020 in. That means 20-point font sizes or greater work best on parts.
Many font types can be machined, but I would recommend against serif fonts leaving them as simplistic as possible to once again improve moldability and legibility. Typefaces such as Century Gothic Bold, Arial or Verdana (san-serif fonts) work well.
It is possible to have features that may be pronounced than text that has been designed into your part. Secondary operations outside of Proto Labs are available including laser engraving, stickers, pad printing and painting.
If you have further questions about applying text to molded parts, or any other questions on designing for manufacturability, please contact our customer service engineers at 877.479.3680 or firstname.lastname@example.org. Make sure to follow our monthly design tips that dive even deeper into subjects around part design for 3D printing, CNC machining and injection molding.