As with any manufacturing process, injection molding comes with its own set of design guidelines, and design engineers who understand these best practices will increase their chances of developing structurally sound and cosmetically appealing parts and products.
Learn about different cosmetic issues that commonly occur on injection-molded parts, and how to eliminate them to improve overall part appearance and performance. This month’s tip discusses sink, warp, flash, knit lines, drag, vestiges, jetting, splay and other cosmetic issues.
Read the full design tip here.
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.
Raised text on part is recommended.
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.