Pushing the edge of the cutting edge
Femap with NX Nastran helps get innovations to market sooner and is critical to entering new markets
Cutting at its best
Key Knife, founded in 1986, is a world leader in chipping, flaking and planing systems for the wood products industry. Each Key Knife system is custom-designed to meet a mill’s specific needs. Sawmills, pulp mills, oriented strand board (OSB) plants and particleboard plants use Key Knife’s innovative technologies to improve recovery, chip/flake quality, production and product quality. The company’s products are sold in North and South America, Europe and Asia.
Key Knife’s R&D department allows the company to maintain its market-leading position by continually incorporating innovative wood-cutting technology into new products. The challenge over the years has been to go from an innovative idea to a marketable product more quickly. “We have one overseas competitor and several others here in the Pacific Northwest. There aren’t that many but we still have to make sure our technology stays ahead,” says John Greiner, a mechanical engineer at Key Knife. The R&D department’s other mission is to help Key Knife diversify into other industries. Currently the company is looking at applying its cutting technology to plastics recycling.
Key Knife’s engineers use the Femap™ with NX™ Nastran® finite element analysis (FEA) solution from Siemens PLM Software in both aspects of the R&D work. Greiner adds, “Femap with NX Nastran speeds time to market, and in the case of new applications where we start out with no idea of the forces or the environment, without this software we wouldn’t know where to begin.”
More user control
Femap with NX Nastran is actually Key Knife’s second FEA system. Originally the company used CosmosWorks, a program that integrated well with its CAD software, SolidWorks. But after a while, CosmosWorks began to seem limiting. “We were looking for more control over the FEA program,” Greiner explains. “CosmosWorks didn’t give us the resolution we were looking for. We couldn’t do some of the problems we wanted to solve and we didn’t have the ability to break the problem down in a way that made sense.”
Key Knife chose Femap with NX Nastran on the recommendation of the local reseller, George Laird of Predictive Engineering, who had performed FEA for Key Knife before the company brought that capability in house. “With Femap we can break things up more, control our mesh more and apply more loads and restraints in ways that make sense to us,” Greiner says.
Predictive Engineering provided a one-week training course in the new software. “We wanted the training because Femap has more options than CosmosWorks and that was different for us,” he adds. “George is fantastic – one of the most knowledgeable people about FEA that I have ever known, and a pleasure to work with.”
Analysis replaces prototypes
Key Knife is still using SolidWorks as its CAD system. Engineers import the SolidWorks geometry (in Parasolid® or STEP format) into Femap to prepare the analysis model. They use Femap when they are designing new wood-cutting systems to see how they function under a known load, either the chipping load (the force required to cut the wood) or the impact load.
“A log is carried toward the cutting head at 200 to 1,000 feet per minute,” Greiner explains. “It may hit other components before it hits the knife and these components must be able to handle that load.” Engineers typically look at displacement plots created by Femap to see how the system moves under these loads. They also use stress plots to get an indication of where the stress risers are.
An important benefit of FEA is that it has allowed Key Knife to significantly reduce its need for physical prototypes. In the past, a new product required between eight and 10, at a cost of approximately $10,000 per prototype and development cycle of two to three weeks each. Today, the company needs only one prototype to verify the operation and safety of a new machine before going into production.
For Key Knife, Femap with NX Nastran provides a better ability to compete in its core business area by helping engineers incorporate new technology into products faster and at a lower cost. Looking to the future, Femap with NX Nastran will help the company weather the ups and downs of lumber business by guiding it toward new applications for its expertise.