The original size of the coaster is (80 x 80 mm). If you want to scale it bigger, I added a version with a thinner bottom part (0.5 mm, the original was 2 mm), so it does not become so massive.

I used PETG to print, so there won't be any problems putting a hot coffee cup on it. PLA should be also fine in most cases.

Printer: Ender 3 Pro 

Supports: No

Resolution: 0.2

Infill: 15

Filament material: PETG