2017 International Forest Industries Magazines April May 2017 | Page 50

Productivity is essential to a successful operation in the forestry and recycling industries, which is why it’s important for companies to continuously seek out ways to simplify machine maintenance, according to Matt Eul, Marketing Specialist with Vermeer’s Recycling and Forestry division. “For horizontal grinders and whole tree chippers specifically, the chip drum and its knife style can have a dramatic impact on performance, as well as the amount of time needed to perform routine maintenance,” he told International Forest Industries. Babbitt versus non-babbitt knives Dull knives can cause unnecessary wear to the machine and inconsistency in chip sizes, which is why regularly sharpening the jobsite. While non-babbitt knives can reduce maintenance times, many traditional non-babbitt knife designs will require additional maintenance time as the knives work their way out of place during operation, and potentially coming into contact with the shear bar. Developing better solution In 2013, Vermeer set out to develop a better non-babbitt knife style. Through research and testing, Vermeer identified and corrected common issues companies working in recycling and forestry applications were experiencing. In the typical non-babbitt knife, the two push screws are placed on the back of the knife and threaded in-between the bolts that clamp the knife down. This configuration allows the blade to “work out” when processing certain materials, Eul said. Jeff Bradley, product manager at Vermeer: “When Vermeer started to explore converting to It may seem like a small detail for many people, but we understand how important knife design is to the overall performance of a machine and how labor-intensive making adjustments and sharpening can be Jeff Bradley, Vermeer knives is important. However, not all manufacturers use the same style of knives. It is common for manufacturers to use babbitt knives on their machines, often requiring the use of a ladle, bench vice, torch and lead file to aid in resizing and sharpening a set of knives. This work requires a trained professional and often will have to be done in the shop since the process involves working with molten metal. Non-babbitt knives are another style offered by manufacturers. Instead of using molten metal, non- babbitt knives add length to the knife using two push screws on the back of each one. When sharpening and adjusting the knives, the user simply adjusts the push screws, which can be performed on the Visit us on Stand 492 The state-of-the-art chipper knives within the Vermeer units a non-babbitt style knife on chip drums, we wanted to make sure our customers would benefit from the switch. “We knew the labour necessary to adjust the size of the knives after sharpening would be significantly reduced, and there was a benefit of no longer having to work with molten metal. “However, the problem of knives working out of place during the processing of large, hard materials remained an issue. Our testing determined that working out of place could lead to the knives contacting the shear bar, which could cause significant damage to the knives and shear bar.” Vermeer developed a solution to this problem by relocating the screws to line up with the bolts that clamp down the knives. This alignment prevents the knife from working out because the end of the screws protrudes into the knife slot and butts up to the clamping screw. Vermeer’s WC2500XL increases productivity and reduces maintenance 48 International Forest Industries | APRIL / MAY 2017 Placing the screws in line with the bolts also allows the screws to act as a shock absorber in the instance the knives encounter a contaminant. Instead of the knife absorbing the damage from hitting a foreign object, the shank of the screws sticking out of the knife body will buckle, helping to minimize the damage. All Vermeer grinders and whole tree chippers utilize this patented non-babbitt knife design in the chip drum mechanism to better meet the needs of recycling and forestry professionals. “It may seem like a small detail for many people, but we understand how important knife design is to the overall performance of a machine and how labour-intensive making adjustments and sharpening can be,” adds Bradley. “The non-babbitt knives on Vermeer grinders and whole tree chippers will help keep you up and running.”