POST

Horner Field Service was recently asked to troubleshoot a vibration issue with a combine. The call came in to Ralph Coonce on a Thursday afternoon. It didn’t take long for Ralph to determine that he was going to send me. I have a strong background in both vibration analysis and farming, having spent years operating and repairing equipment, including combines. Growing up on a farm, I often worked in an auger wagon, planted crops, and occasionally ran the combine— typically reserved for the equipment owner. This hands-on experience gave me a solid understanding of how combines function. When Horner Field Service received a call about a vibration issue with a combine, I was well-prepared to tackle the problem and headed out the next morning. Before I get into the nerdy analysis, I should explain the back story of the company that called us. Ben Dillon, who grew up on a farm in Logansport, Indiana, founded his company with a vision to revolutionize combines. Frustrated with traditional combines holding only 200 bushels, he aimed to create one that could hold 1,000—eliminating the need for an auger wagon and allowing a full truckload per dump. Starting in the 1990s, Ben modified two Case IH combines before perfecting his design, which now sits in his Logansport barn. The company combines, tested in Indiana’s high-yield soybean fields and Kansas labs, are designed to hold a semi-load of grain, streamlining harvesting efficiency. Now, back to the testing. When we first arrived on site, we were told we only had 2 hours to work. Beans can be cut around 10 or 11 am when the dew dries off. Until then, beans are too tough, and the knives of the combine head will plug up. When the time was right, they were going to cut, period! To make a long story short, we found that the oscillating frequency of the knives in the head was almost a direct match to the natural frequency of the cab assembly. There are eccentric oscillators on each side of the 35-foot head that cause the sickle bars to move back and forth. This is what cuts the stalk. The black rotating wheel that we are all familiar with is what pushes the material on to the belts that feed into the machine. Since the cab assembly had a natural frequency close to the oscillating frequency of the knives, the combine operator was complaining about excessive vibration in the cab. Nobody wants to spend 12 hours in a cab that shakes. Tyler Wilson and I were able to identify the frequencies present and point them to the source of these frequencies. Before the combine was sent in the field, we were asked to explain our findings to a group of about 6 Brazilian engineers. They seemed to know exactly what we were talking about, and they looked like they were excited to go to work resolving the issue. To tune out the vibration issue in the cab, Tribine will have to change the stiffness,
mass, or damping of the cab assembly. Another option would be to change the speed of the sickles in the head. But we were quickly told that these needed to run at 450 rpm for the best performance. This tuning will likely require the use of multichannel equipment and detailed analysis that the EMDS group will need to conduct. Horner Field service was able to jump in with a very small window of opportunity to point the design engineers in the right direction.