About the only way to make it raccoon proof is to raise it high enough so that the cats can still jump up, but the raccoon can not. Raccoons can climb, but they are not good jumpers. What you could do is take and old table that is at least 3 feet tall and then wrap a piece of luan around the table and fasten it to the table. Let it hang down between 6 inches and 1 foot from the table top. Then just put the feeding station on top of the table. You may or may not have to raise the table a little higher by adding some 4X4 legs longer than the original ones.
Make sure that there are no trees or branches that the raccoon could use to drop down from.
Google search "raccoon proof cat feeder" to get lots more.
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On a somewhat separate note.
Anyone that has cats that they are trying to relocate to a barn and wants some place to keep the cats while they acclimate to the new surroundings might want to try this:
Yet from my experience of trying to keep the raccoons out of the food for years, it is next to impossible. I had tried putting some up on a tall table with flashing all around it. Then I had a feral villa my DH made with a very small hole cut out. We thought no way could a fat raccoon get inside. Well, it did.
I hope you succeed in finding a way. But for me the only way to ensure the raccoons stay away is to pick up all food at night.