To not use a mat, a platter must be made with relief for the thicker parts of a record in order for the read surface to have its best chance of coupling with the platter.
FWIW, I typically NEVER use a mat on Delrin or acrylic platters.
Had lots of success with the 5mm thick Achromat on suspended vintage Thorens, AR & Linn tables (2-piece platters) all with good grip and no slipping. Have had slipping on Rega one piece platters which required thin double-sided (carpet) tape to grip.
The current Luxman mat is a sweetheart on every high mass design system I’ve tried it on. Record weight &/or clamps NOT required.
FWIW, I typically NEVER use a mat on Delrin or acrylic platters.
Had lots of success with the 5mm thick Achromat on suspended vintage Thorens, AR & Linn tables (2-piece platters) all with good grip and no slipping. Have had slipping on Rega one piece platters which required thin double-sided (carpet) tape to grip.
The current Luxman mat is a sweetheart on every high mass design system I’ve tried it on. Record weight &/or clamps NOT required.