Design and experiment of stalk pressing type cotton field mulch film collectors

A mulch film collector is one type of picking mechanism in the recycling of mulch film at present. However, the conventional configuration cannot fully meet large-scale production, such as severe film clamping, the requirement for cotton stalks crushing, and low film content. The existing drum-type pickup mechanism of mulch film has also serious film enwinding and a low film content rate of recovered mulch film. In this study, a mulch film recycling machine was developed with the stalk pressing type in the cotton field. The mulch film pickup mechanism with drum type was selected along with the one-film and six-row machine cotton harvesting and planting mode in Xinjiang. The cotton stalks' recycling and reliability greatly contributed to the resource utilization of cotton stalks. A box was added to bundle the stalk. A guided pickup roller of mulch film was built with anti-winding and impurity cleaning functions. A pneumatic film removal device was also added to rapidly remove the film. The film picking, film stripping and contamination removal operation were realized in the improved device at one time. The structural parameters of the stalk box, mulch film picking roller and film removal mechanism were also determined using kinematic and kinetic analysis. The working parameters of key components were analyzed after optimization. The front tilt angle of the stalk box was designed to be 30° considering the congestion and the forward resistance of the machine. The motion position and oscillation of the hook teeth at each station of the film pickup roller were combined to clarify the motion trajectory of the roller center. The mathematical model of the slide profile curve was established using the analytical method. The kinetic analysis of the film pickup roller was carried out, where the rotation speed range of the roller was determined to be 41-68 r/min. A systematic investigation was implemented to explore the relationship between the full pressure at the outlet of the film removal hood and the rotation speed of the film removal shaft using aerodynamics. The rotation speed of the film removal impeller was 980 r/min. To verify the operational performance of the device, A three-factor, three-level response surface test was conducted with the machine advancing velocity, the depth of hook-tooth into the soil and the rotation speed of the film pickup roller as the test factors, and the film pickup rate and the film content rate as the test indexes. The response surface model of each factor was established to optimize for better operational performance. The test results showed that the significant effects of the test factors on the film pickup rate were ranked as the rotation speed of the film pickup roller, the machine advancing velocity, and the depth of hook-tooth into soil. The significant effects of the test factors on the film content rate were the rotation speed of the film pickup roller, the depth of hook-tooth into soil, and the machine's advancing velocity. The best operation was achieved, when the rotation speed of the film pickup roller was 65 r/min, the machine advancing velocity was 5 km/h, and the depth of hook-tooth into the soil was 50 mm. The optimized performance was verified for the average film pickup rate was 86.8 % and the average film content rate was 14.9 %. The findings can provide a strong reference to design the subsequent machines for the stalk-collect mulch film.