Silhouette Cameo

The blade level The Thickness setting
The blade level controls how far the blade is exposed in 0.1 mm increments. This accommodates for how thick the material is. For example, a blade level of 1 = .01 mm, a level of 2 = 0.2 mm, etc. If you have a material such as cardstock where the actual thickness is 0.3 mm, setting the blade to a higher exposure (such as 0.6 mm or a setting of 6) would mean you are exposing the blade beyond the actual depth of the material. This does not allow the blade to cut better. It just exposes more of the blade and if extending beyond the actual thickness of the material can dull down the blade tip much more quickly (or in extreme cases break off the tip). This would then result in ragged cutting results. From that point on, you would then have to expose the blade to a higher level because a setting of 6 would actually be only exposed 0.3 mm since you had worn down the excess tip beyond the material's thickness. We would thus discourage attempts to overexpose the blade to try and get a "better" cut.

Ref: Silhouette America - FAQ - Finding correct cut settings for materials (Test Cut feature) - Printer Friendly - https://www.silhouetteamerica.com/printer-friendly/faq/test-cut-feature