Designed with a strong polyester film backing and sharp diamond mineral, the 3M™ Diamond Microfinishing Film Roll 675L delivers fine finishes on hard metals like thermal spray coating, ceramics, carbides, chilled iron and granite. High-quality Materials for Micro-finishing 3M™ Diamond Microfinishing Film Roll 675L securely anchors micron-graded diamonds to a polyester film backing. Known for its strength and resilience, the polyester film backing keeps the abrasive from skidding or deflecting when run. This backing helps the superabrasive belt stay taut and tough so that it can withstand heavy-duty finishing. The belts are also color coded by grade to help you reduce the risk of selecting the wrong grade. Waterproof Backing Polyester film backings are also water resistant, so the abrasive may be run with a wet surface lubricant, which helps wash away unwanted swarf and debris and keeps the abrasive running cool. When used in roll form for a process like superfinishing, our 675L roll enables slow abrasive feed rates and requires fewer steps, because of its durability, which in turn can reduce costs. Tips for Achieving Desired Roughness Average Many micro-finished products require a specific Ra, or roughness average. To obtain the desired Ra when applying thermal spray coatings, we recommend following a unique sequence of steps tailored to the substrate. A Ra of 2.5 to 5 on Tungsten Carbide, for example, will likely require a film with grade 74u followed by films 45u, 30u and 20u. It is important for operators to consider these factors – Ra and substrate – when selecting the grade of film for this belt. Overall, this micron-graded diamond abrasive delivers the desired finish without compromising the integrity of the substrate. Its strength and versatility make it a suitable abrasive for your finishing needs.