| As the core part of a mixing plant,the double horizontal shaft mixer,so far,has had its research and development basically finalized and matured,but its processing level and efficiency still have a large gap.With the proposal of German industry 4.0,the fourth industrial revolution has come and China's manufacturing industry is developing in the direction of intelligentization.For welding of double horizontal shaft mixer tanks,the Company used to adopt spot welding with grouped simple tooling and the manual welding cannot effectively ensure the welding quality of the tanks,thus to result in serious dimensional deviations and ugly weld joints,which has directly affected the assembly quality of mixers and has reduced the service life and competitiveness.Moreover,the welding post adopts a ground layout featuring comparatively low welding efficiency.According to the process improvement plan ofthe Company,the quality and efficiency shall be improved on welding of the mixer tanks,but the current welding mode cannot meet the improvement requirements.Based on sufficient investigation and research and response to the national requirements for intelligent manufacturing,to design a mixer tank automatic welding production line able to meet the capacity demands of the Company in the next decade can promote the intelligentization process of the mixer tank manufacturing,improve the quality control ability,enhance the core competitiveness of mixers and lead the mixer tank manufacturing industry at home and abroad.First of all,locate the development trend by investigating and researching the current situation for the manufacturing of double horizontal shaft mixer tanks at home and abroad.Determine the annual output of the mixers in accordance with data statistical analysis and the Company's planning for the next decade.According to the requirements,calculate the production take time,determine the daily output and unit time and analyze the problems to be solved when the welding of mixer tanks is upgraded from manual to robot welding.Then in the original welding line workshop,carry out rearrangement,minimize the material delivery distance,avoid the cross repetition,enable quick flow,avoid stocking storage and thus fully consider the crane load rate.According to the technological process for automatic welding of double horizontal shaft mixer tanks,determine the tooling,fixtures,welding robots and repair welding solutions necessary for each mixer welding post and make a preliminary layout and personnel allocation plan for the automatic welding production line.Carry out the detailed design of the workstations for double horizontal mixer tank welding production line:rib plate pairing workstation,end plate pairing workstation,end plate welding workstation,tank pairing workstation,tank welding workstation and tank repair welding workstation.The rib plate pairing workstation mainly uses such a structure of mechanical positioning and electromagnet clamping to facilitate the quick loading of workpieces.The end plate pairing workstation is mainly to ensure the pairing of the tank flange and the tank body and carry out detailed analysis of the structure of the flange at the key position.The end plate welding workstation should mainly consider the robot selection and the end plate loading mode as well as the weldability and welding effects.The tank pairing workstation will determine to use hydraulic clamping and inner positioning or not based on the analysis of the tooling pairing program.The curved plate can be tightened by means of a tie rod structure and can be self-locking.The curved plate positioning can be divided into fixed curved plate positioning and telescopic curved plate positioning.All use hydraulic control.The end plate is positioned subject to three-claw hydraulic compression.The tank,welding workstation undertakes to compare the two kinds of schemes with the mixer tank mouth kept up and down,simulate each scheme and calculate weldability of the tank,finalize the clamping program;the analysis results show that the two schemes shall be considered in order to guarantee the weldability and two robots shall be equipped with their mouths kept up and down respectively for welding.Then,design the tank fixtures according to different clamping modes.Finally,design the tank repair welding workstation.Design the control system of each workstation,for example,the rib plate pairing workstation,mainly to magnetize the magnets one by one and demagnetize them at a stroke.The tank pairing workstation shall consider the sequence of the fourteen actions during tooling clamping and distribute the button positions according to the action sequence and button functions when the electric control panel is being designed.In this way,the tooling hydraulic system can be controlled to complete the tooling actions.By modeling the mixer tank,apply torque and pressure to it.Use the stress and strain cloud diagrams to locate the maximum stress strain,determine the weld joint pattern and focus on this point while the welding robot is being programmed.Let five mixer tank automatic welding production lines accept commissioning in a batch to find out the existing problems,put forward the countermeasures,measure the production take time and compare it with the previous one in order to verify whether the design capacity demands have been satisfied.After the demands are satisfied,the next step is mainly to massively produce mixer tanks,collect a large amount of data from practical production,carry out further specification and standardization of the workstation for pairing mixer tank parts,increase the weldability of the welding robot and thus optimize the production take time. |
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