Design and Key Technologies for an Integrated Square Bale Straw Baling and Net-Wrapping Mechanism

China boasts abundant straw resources but grapples with notable challenges in straw processing: returning straw to fields can lead to soil compaction and aggravated pests/diseases, while baled straw for off-field storage and transportation tends to scatter. Additionally, domestic netting technology for square bales remains underdeveloped, and imported equipment is ill-suited for small-scale farmers. To tackle these issues, this study developed an integrated straw baling and netting machine by modifying the 9YFSG-2.2 square straw baler. It integrates a conveying mechanism, an offset crank–connecting rod compression mechanism (300 mm crank, 885 mm connecting rod), a two-stage gear-driven net-wrapping mechanism (with hollowed-out large gears for weight reduction), and a sensor-controlled net-cutting device, forming a complete workflow of “straw pick-up–shredding–conveying–compaction–net wrapping–net cutting”. Via coupled simulation using RecurDyn 2019, EDEM 2020, and ANSYS Workbench 2018, straw particles were modeled as 28-mm-long segments (composed of three 7 mm spheres). Simulations showed straw compaction in 0.48 s, with the compression chamber and plate having equivalent stresses of 0.2767 MPa and 173.44 MPa and maximum deformations of 0.0012 mm and 0.66 mm—both well below structural steel’s yield strength. Field tests in Xinxiang, Henan (straw moisture 30.03%), yielded results exceeding standards: 99.4% bale formation rate, 96% regular bale rate, 93% drop resistance rate, 170 kg/m3 bale density, and 12 s per bale efficiency. Controlling netting time further boosted efficiency and reduced consumption, successfully realizing integrated straw baling and netting.