What is the difference between the stainless steel and the stainless sintered alloy?

Stainless steel

It is made by cutting a block of stainless steel.

It is used for a roller of the spatter-prevention type limit switch because spatter hardly adheres to it. 

Stainless sintered alloy

It is made by alloying stainless steel powders by applying pressure and heat in a mold. Stainless steel powders with oil soaked through their particles are used for a roller.

Roller abrasion and smear mark appear at the same time, and thus abrasion resistance of the roller is enhanced.