Development Of Fully Automatic Packaging Machine For Spherical Fruit Net Cover

The foam net cover has good performance of vibration reduction and shock absorption.It can effectively protect fruit and reduce the mechanical damage of fruit during transportation when used in fruit packaging.Therefore,it is widely used in the domestic fruit packaging industry.However,at this stage,there is a lack of net cover packaging equipment with high packaging efficiency and high degree of automation in the market.The fruit net cover usually uses the human power package.This does not meet the needs of low productivity and high violence and the needs of markets and the objectives of developing national agricultural modernization.In order to realize the automatic packaging of fruit net cover,reduce packaging costs and improve packaging efficiency,this paper takes typical spherical fruit apples as the main research object,and designs a spherical fruit net cover automatic packaging machine that can automatically load,adjust apple posture and netting packaging based on the previous research results of the research group.The main research contents and conclusions are as follows :(1)Determination of the overall size of apple and net cover.In order to obtain the basic data required for the device design,this paper carried out the measurement test of the overall size of apple and net cover.Experiments show that the height of apples is mainly distributed between 70mm-80mm;apple fruit diameter is mainly distributed between 75mm-90mm;the outer diameter of the depression on the end of apple navel is mainly distributed between 27mm-29 mm.The outer diameter of the pith of apple fruit is mainly distributed between 25mm-28 mm.The average weight of apple is 236.62 g,and the maximum weight is 287.5g.The average diameter of single foam strip is 2.91 mm.(2)Design of the overall scheme of the fully automatic packaging machine for spherical fruit net cover.Based on the analysis of the research status of the net cover packaging machine,this paper determines the overall design requirements and main performance parameters of the fully automatic packaging machine for spherical fruit net cover,and clarifies that it is mainly composed of feeding device,fruit attitude adjustment device,fruit grabbing device and mesh packaging device.After comparing and analyzing the commonly used feeding scheme,fruit attitude adjustment scheme,fruit grasping scheme and the existing mesh packaging scheme of the research group,this paper designs the conveyor belt paving slide feeding device,friction wheel fruit attitude adjustment device,vacuum sucker fruit grasping device,saw blade cutting device and fruit feeding device suitable for automatic feeding.Finally,the overall scheme and working principle of the fully automatic packaging machine for spherical fruit net cover are determined,and the working flow chart is drawn.(3)The design,simulation research and selection of the key parts of the fully automatic packaging machine for spherical fruit net cover.In the feeding device,the number of shunt slides is designed to be 5 columns,the length is designed to be 300 mm,the bottom end is designed to be ’ v ’ shape,and the front end is designed to be 60 degree angle.At the same time,the selection of conveying chain,drum,height limit brush and motor is carried out.In the fruit posture adjustment device,the diameter of the friction wheel is designed to be 27 mm and the width is designed to be 10 mm.The transmission mechanism of the friction wheel is composed of synchronous belt and bevel gear,which can realize the rotation of the friction wheel in both horizontal and vertical directions.At the same time,the loading bowl is designed as a hemispherical container with a diameter of 100 mm and a circular hole with a diameter of 32 mm at the bottom.Secondly,the measurement test of the friction coefficient of apple surface was carried out.The test showed that the average static friction coefficient between apple and sprayed stainless steel plate was 0.334,and the average dynamic friction coefficient was 0.248.The average static friction coefficient between apple and photosensitive resin plate was 0.216,and the average dynamic friction coefficient was 0.150.Then Adams was used to simulate the working process of the fruit attitude adjustment device.The results showed that when the friction wheel speed was 1 lap per second and the contact friction time with the apple was 2seconds,the attitude adjustment success rate of 12 apples with different initial attitudes was100%.Finally,the motor and cylinder were calculated and selected,and the strength of the conveyor chain was checked.After theoretical calculation in the fruit grabbing device,the vacuum sucker model L92 and the vacuum generator model CV-05HS-CK were selected for fruit grabbing operation,and the relevant driving cylinders were selected.In the cutting device,the sawtooth is designed as an isosceles triangle sawtooth with a tooth pitch of 5mm and a tooth height of 3mm.The transmission mechanism of the saw blade adopts the eccentric wheel connecting rod slider mechanism,and the eccentricity of the eccentric wheel is designed to be3mm;Secondly,it is determined that the material of the saw blade baffle is a special cutting plate composed of rubber and PVC.At the same time,the working process of the saw blade cutting device is simulated by Adams software.The results show that the maximum relative displacement of the two saw blades is 6mm and the maximum driving torque is 38.905 N·mm when the eccentric wheel speed is 6 turns per second.Finally,the calculation and selection of the motor are carried out.In the feeding device,the size of the fruit is designed to be 70 mm in diameter,20 mm in height and 2mm in thickness,and the strength of the chain is checked.(4)The design of aerodynamic system and control system for the fully automatic packaging machine for spherical fruit net cover.According to the working principle of the fully automatic packaging machine for spherical fruit net cover,the pneumatic system of the prototype was designed,the gas path design of the whole machine was completed and the gas path schematic diagram was drawn.According to the working principle and control requirements of feeding device,fruit posture adjustment device,fruit grasping device and net packaging device,the hardware of controller PLC,touch screen and sensor are selected.Simultaneously,the I/O address is assigned based on the operational procedure and control mechanism of each equipment,and the external wiring diagram and control flow chart of the PLC are delineated.Subsequently,the corresponding device’s control program is scripted via GX Works2 and Xinjie PLC programming software,while the configuration interface of the net packaging device’s touch screen is fashioned using Mcgs Pro configuration software.(5)The prototype trial and verification test of the fully automatic packaging machine for spherical fruit net cover.According to the overall design scheme,the required materials were purchased and the prototype was built.At the same time,the performance test of the prototype was carried out.The test showed that the prototype could successfully complete the loading,posture adjustment and net cover packaging of apples.The packaging success rate was 96.6%,and the packaging efficiency was 2.054 s/piece,which met the design requirements.