Using new rotary knives on a dull worn anvil will produce unsatisfactory results. However, many companies still use new knives against a dull die block, which results in the new knife producing a rough cut. The problem with this method is that the die blocks dull at about the same rate as a rotary knife, and then require replacement at a considerable cost to the company, typically about 5-6 times the price of a knife.
One of the services I offer is the sharpening of die blocks to factory like new condition for about the cost of a rotary knife. Die blocks can be sharpened multiple times, avoiding the purchase of a new block every time it becomes dull. The recess can be turned down further, resulting in a true factory edge. Solid slitter knives can also be sharpened to a certain point, although excessive sharpening will make the outer diameter too small for use. At this point, the knife must be discarded.
I hope to share this new technique with many companies, and I am currently offering a free trial of my knife sharpening to all new customers!