Aug 20, 2015 Off Comments in Laser Cutting by

In the early days of industrial CO2 lasers, a fair amount of attention was focused on pursuing laser cutting abrasive (sandpaper) discs (FIGURE 1) as a viable market. The logic was clear, as a laser solution would eliminate the need for hard tooling. However, the economics were not favorable, as the capital cost of implementing laser technology was just too high and the production rates were too slow when compared to existing die-cutting solutions.

Additionally, those die-cutting processes were well established and there were no compelling reasons to pursue a laser solution because die cutting did not present challenges that a laser process would solve. In recent years, that has changed. This article reviews the history of producing abrasive sanding discs from well-established die-cutting practices to a laser process required to meet new demands placed on abrasive disc manufacturers.

Abrasive disc production

Abrasive material is produced in 48-in.-wide or wider master rolls, with the abrasive grit on one side of the roll substrate and a means of attachment to the backup pad on the other. The attachment methods are typically a pressure-sensitive adhesive or, more commonly, a polymer ‘loop’ material that will physically bond to the ‘hook’ surface of the backup pad (think Velcro). While the material handling systems for die cutting and laser cutting are different, they all require the ability to unroll the incoming material, process the material by performing a periphery through-cut and, if needed, produce dust-extraction holes on the disc surface, singulating the disc from the roll, removing the unused waste skeleton, and stacking the discs into counted piles for insertion into boxes for purchase by the end user.

Abrasive disc production has always been the domain of flat-bed die cutting, and for good reason. Even though lasers offered advantages, die cutting was (and in many cases remains) the most cost-effective means of production, especially for discs that only require a periphery cut or a periphery cut with large dust-extraction holes.

Flat-bed die systems use an upper platen that is attached to a hydraulic ram. The steel rule die is secured to the platen and once the hydraulic ram is actuated, the steel rule penetrates the abrasive material and the part is produced. These systems are capable of production rates up to 60 strokes/min. Additionally, if the die board is steel-ruled with three 6-in.-diameter discs, it is possible to produce 180 discs/min, resulting in high production rates for a nominal investment. A steel-rule die also has a long life and low cost because the die only costs a couple-hundred dollars and it self-sharpens while die cutting the abrasive. With this background, it is easy to see why die cutting has been the process of choice for most abrasive disc-processing applications.

Read more: Cleveland Ohio Laser Cutting: CO2 lasers advance next-generation abrasive disc technology