Part Details Review
| Lettering |
Molded-in lettering is frequently used in injection molded parts as an economical substitute for printing or labeling. For economic reasons, lettering is generally engraved in the mold which appears as raised letters in the parts. Machining raised lettering in the mold is more expensive and often unnecessary.
Engraved lettering in the mold, if not done properly, presents problems in the molded part in the form of unsightly tear drops or flow swirls around the letters. This defect is caused by the inability of the melt to push the air out of the letters smoothly.
To help the evacuation of air, the designer should radius all corners of the letters; keep lettering depth under 0.010", and make the width of the lettering lines at least double their depth . The sidewalls should have a draft angle of at least 30°.
Letters raised higher than 0.010" are unnecessary as they seldom wear out during the life of the part.
