An Original UV Adhesive Watermelon Grafting Method, the Grafting Device, and Experimental Verification

Abstract

This study is aimed at traditional vegetable grafting using a large number of plastic clips, which cannot be recycled in time and cause serious pollution within the planting environment. This paper proposes a new grafting method based on a UV adhesive instead of plastic clips. First of all, a UV adhesive spray grafting device was designed. The structure includes seedling adsorption positioning mechanisms, a butt joint mechanism, a handling mechanism, a spray valve, a UV curing lamp, etc., to facilitate the adhesive spraying. For the rootstock and scion, a horizontal, lateral seedling and negative pressure adsorption and positioning method is adopted, with fluid dynamics simulation of the diameter and quantity of the adsorption holes in the rootstock adsorption mechanism carried out using Fluent 2022 R1 software and completion of the optimization of the parameters of the adsorption and positioning mechanism. The fluid volume method is used to simulate the adsorption and positioning mechanism. For optimization, the volume of fluid method (VOF) and the discrete particle method (DPM) are used in a coupled simulation of the UV adhesive spraying process, and the value range of the spraying influencing factors is determined: the selected glue pressure, atomization pressure, and spraying height for three-factor, three-level orthogonal simulation. A grafting test is also verification, deriving the significance ranking of their impact on the success rate of the grafting: atomization pressure > spraying height > glue pressure. Under the condition of a 0.25 Mpa atomization pressure, a 0.15 Mpa glue supply pressure, and a 10 mm spraying height, the grafting success rate for watermelon was 100%, the effective spraying rate was 83.03%, the healing success rate was 94.5%, and the length of the film was 7.86 mm. The results of the study can provide a research basis for the research and development of new types of spraying and grafting robot technology.