Game Manufacturing 101: Dice, Domino, & Letter Tiles Inking
Applying ink to the debossed (molded) numbers, letters, or custom images is a very old and simplistic process.
First, the dice or letter tiles are places in simple wooden trays in rows. Typically, a few hundred are inked at the same time.
The ink that is used is a fast drying acrylic ink. As you can see in the photo, it is applied by hand, using a small bottle that has a very fine tip. The ink is then “flooded” onto one side of the die or tile, which results in ink getting applied to both the molded area as well as the outer flat surface around it. After the ink dries (which is within a few minutes), the outer flat surface is then wiped with a small cloth that contains a solvent material that removes the bulk of the ink that is outside the molded area.
The next step is to rotate all the dice in the tray so that the next (uninked) side of the die is face up. Then the inking is started again.
After all the sides are inked and wiped clean, the dice or tiles are then put into wooden bins that are spinning (like a cement mixer). This step removes any residual ink that is left on the flat surfaces.