25º set. 2012
With the acquisition of K2 Plastics, Gleason is now a source for strong,
quiet thermoplastic gears containing no weld-lines, with a thru-hole and no secondary machining. "Coupling Gleason's arsenal of nonlinear contact FEA and advanced gear design software, with the latest engineered thermoplastics, Gleason-K2 Plastics' gears are a top choice for all demanding plastic gearing applications," says Klaus Kremmin, general manager of the Gleason-K2 Plastics division of The Gleason Works. Weld, meld or knit lines in a molded gear are where two or more material flow fronts meet. Weld lines create a weak point in the gear, where material strength can be just a fraction of the normal material strength, particularly in fiber- or glass-filled resins. The result is that the typical 2 to 4 times safety factor isn't sufficient for gears with weld lines.
This is also why we continually see frustrated customers who had gears designed and manufactured elsewhere upset with their cracked gears," Kremmin says. "The gears cracked at the weld line due to thermal and contact load cycling beyond the weld-line limits. As the gearing engineer, you are forced to test for weld-line strength yourself to properly select an appropriate safety factor for your design since material data sheets do not provide this information." Gleason-K2 plastic gears can provide optimized gear designs, verified by FEA analysis. In some cases, depending on the material, an additional 1,000 percent improvement in strength can be achieved by the elimination of the weld lines.
Learn more about Gleason K2 Plastics here