Design and processing parameter optimization of automatic grafting machine for oil tea seedling

Oil tea cultivation offers significant economic and ecological benefits and has seen rapid growth in recent years. Traditional manual grafting of oil tea scions is costly, with low controllability of quality, while existing oil tea seedling grafting devices cause high mechanical damage to seedlings, limiting their application. This paper introduces a motor-driven automatic grafting and shaping device for oil tea seedlings with a low damage rate, propelling the continuous development of the oil tea industry.

The paper is grounded on an analysis of the grafting principle and selection of the grafting process. Key components such as clamping and fixing, cutting and shaving, and a centering apparatus are formulated based on geometrical parameters obtained from random samples of rootstocks and scions. To assess the design's validity, the Abaqus software simulates the dynamics of seedling centering during grafting. Furthermore, a response surface and a multi-objective optimization model were established using Design Expert software to optimize key parameters in the grafting process.

Dynamical simulation results indicated that the maximum deformation of rootstocks during grafting is 0.416 5 mm, with seedling clamp diameter ranging from 3.0-3.7 mm. The average offset of rootstocks post-centering is 0.066 7 mm, 2.7% of their axial diameter, demonstrating the device's excellent stability and grafting quality assurance. Optimal centering speed, grafting depth, and seedling opening angle of 30.52 mm/s, 53.55%, and 6.89° were identified, respectively.

The device designed in this study uses multiple electric cylinders to automate the grafting of oil tea seedlings, reducing the centering damage rate and providing technical support for the advancement of the oil tea industry. It also offers insights for the design of automated grafting devices for other agricultural and forestry plants.