The purpose of this pet feeder is to keep ants out of the pet's food. This design uses a 2L reservoir (discarded soft drink bottle) of water to create a shallow water-filled moat that ants will not cross. If salt water is used in the moat, slugs may be discouraged.
This is designed to print in three parts: the tray for the water (10.4cm x 20.6cm x 1.7cm), the bowl holder (13.2cm x 13.2cm x 3.3cm); and the bottle ring (11.7cm x 11.7cm x 3.5cm). You must supply the bottle and the bowl. My bowl shown in the photo is about 12cm diam at the bottom of the tapered base, and about 16.5cm diam including the rim.
To assemble: Screw the bowl holder onto the tray; slide the bottle ring onto the bottle; fill the bottle with water; and then hold the tray upside down while screwing the bottle onto the tray. Quickly flip the assembly upright. Put the bowl with food in the bowl holder.
Concepts: Atmospheric air pressure prevents the water from leaving the bottle as long as the air inside the bottle is at very low pressure. As the water in the tray evaporates, the water level in the tray will lower and will allow some air bubbles to enter the bottle. A small amount of water will flow out of the bottle until the air pressure in the bottle is reduced again to very low pressure. The purpose of the bottle ring is to reduce the amount of deformation of the bottle as the reservoir empties over time. The bottle ring will help your bottle keep it's shape over repeated cycles. Keep debris from blocking the water exit in the tray.
I used PLA.
How I Designed This
I used Blender.