1 Introduction In the modern automobile manufacturing industry, it is the development trend of today's international automobile manufacturing industry to realize full automation of the entire process of automotive parts from rough to finished packaging production. There are many precedents for success in developed countries. In recent years, our factory has successfully applied 13 gantry robots for automatic loading and unloading, indexing, and inverting transportation devices for the automatic processing of car body and cylinder head provided by Xiangfan Automobile Co., Ltd. Xiangfan factory, achieving the complete manufacturing process. automation. The gantry robot changed the traditional logistics method, effectively improved the working environment, reliably ensured the product quality, greatly improved the labor productivity, freed the workers from the heavy physical labor, and made the automobile manufacturing technology a brand new one. Level. 2 How the gantry robot works The gantry robot appearance is shown in Figure 1: Figure 1 appearance of the robot 2.1 The main technical parameters Rated load: 250kg, which transports parts weight 40kg Figure 2 C axis transmission diagram 2.4 The gripper is used as a gripper for carrying the workpiece. It is driven by two cylinders and the left and right grippers clamp the part. The left and right splints travel 50mm each, and they are run on a rolling guide. Take a cylinder part as an example, the holder 3 Key Manufacturing Technologies 3.1 Beam Manufacturing Beams are the most important and difficult parts for robots. The success of manufacturing is directly related to the success or failure of the development of gantry robots. Beam diagram shown in Figure 3. Figure 3 beam diagram The beam is processed by welding the square tube and the post plate. Square pipe material 10 steel, specifications 300mm × 200mm × 10mm. Plate material 45 steel. An inlaid steel rail and a rack are mounted on the binding surface of the gluing board, and the entire robot is hung on the rail by contacting the rail with the rail. In order to ensure a positioning accuracy of ±0.25mm, a running speed of up to 36m/min and an acceleration of 0.6m/s2, very stringent requirements are placed on the static accuracy and dynamic accuracy of the beam itself. Assembly requires rails, racks installed in the beam, the linearity, parallelism is not greater than 0.06mm/3500mm, manufacturing requirements beam plate welding straightness, parallelism must ensure that not more than 0.10mm/3500mm. Only when such accuracy is achieved can the roller and the guide rail maintain a good contact stiffness, and the gear and the rack mesh well and meet the application requirements. 4 Conclusion The gantry robot will be developed in serialization, and the development of a three-dimensional and more than 6m crossbeam robot will be a new topic. Psa Nitrogen Generator,Psa Nitrogen Making Machines,Cryogenic Liquid Nitrogen Plants,Psa Nitrogen Making Machine Jiangsu Minnuo Group Co.,Ltd , https://www.mingngroupcn.com
The gantry robot developed by our factory is the first one in the domestic automobile manufacturing industry. This project is the "National Key Scientific and Technological Project of the Ninth Five-Year Plan" of the Ministry of Machinery Industry. After two years of use, it proves that this technology is at the leading level in China. 
X axis maximum working stroke: 2500mm
X axis maximum speed: 36m/min
X axis maximum acceleration: 0.6m/s2
X axis positioning accuracy: ±0.25mm
Z axis maximum working stroke: 500mm
Z axis maximum speed: 24m/min
Z-axis maximum acceleration: 0.4m/s2
Z-axis positioning accuracy: ±0.25mm
A-axis rotation angle: 0° to 180°
A axis rotation speed: 45°/s
C-axis rotation angle: 0° to 270°
C-axis rotation speed: 120°/s
2.2 X, Z axis linear drive system X, Z axis of linear motion are the motor through the reducer drive gear and the X-axis beam, Z-axis studs on the fixed rack roll, drive the moving parts along the hardened steel insert rail motion . The position accuracy and movement accuracy of the robot's work performance are two important indicators. The former determines whether the robot can meet the accuracy requirements and the latter directly relates to whether the robot can adapt to the requirements of the production cycle. In order to meet these two requirements, the basic requirements for smooth operation of robots should be solved. The factors affecting the smoothness of the work, in addition to the structural rigidity and earthquake resistance, are mainly the acceleration and the mass of the moving parts. The higher the mass of the moving parts and the higher the acceleration, the stronger the vibration and impact will be. For this reason, we use imported motor reducers to ensure the transmission of the movement and reduce the weight. The connection of the motor shaft and the gear is transmitted through the elastic deformation of the inner and outer sleeves. There are four pairs of roller sets on each of the X-axis and Z-axis moving parts. In order to reduce weight, roller bracket material chooses aluminum. The pre-tightening and clearance between the roller and the guide rail is achieved by adjusting the eccentric shaft of the roller. These measures effectively reduce the weight of the moving parts, eliminate the gap of the motion transmission chain, reduce the impact energy, and ensure the positioning accuracy and movement accuracy. .
2.3 A, C axis rotation system A axis rotates about Z axis, A axis rotation range is 0°~180°, which is realized by the cylinder drive rack and gear.
The C-axis rotates about the X-axis, and the C-axis rotates from 0° to 270°. The large-toothed pulley is driven by the telescopic motion of the cylinder rod, and the small-toothed pulley is rotated by the toothed belt to realize the horizontal axis. Rotary motion (see Figure 2). The reason why the 270° rotation angle is adopted is to completely remove the accumulated dust and ensure the cleanliness on the raceway. 
With 40 holes positioned, left and right clamping plates are equipped with 3 to 5 limiting blocks to ensure sufficient strength and rigidity, and to prevent the parts from rotating during the turning process. After the clamp stroke is in place, each limit block has a clearance of 0.2 to 1 mm from the limit of the part, which is used for limiting instead of clamping. Determining the position of the center of gravity of the clamped parts during the design process is a very important design element. If the center of gravity cannot be determined, it will cause the impact during the rotation and the toothed belt to break. The center of gravity of the holding part is determined using CAD.
2.5 Z-axis balancing device In addition to ensuring the linear accuracy and positional accuracy of the Z-axis, it is also necessary to ensure that the coordinates do not drift when there is a load and no load, and to ensure self-locking ability when there is a load, so the balance The device is very necessary. When the robot is working, the pressure of the airway system is 0.4-0.5MPa. When the Z-axis moves downwards, the cylinder plays a balancing role, ensuring the smoothness of the Z-axis movement and reliable positioning accuracy and movement accuracy. In addition, under the premise of ensuring that the components of the Z-axis system are sufficiently rigid, it is also necessary to reduce the weight as much as possible.
2.6 The electrical system adopts common motor speed reducers and pulse encoders in consideration of economy and utility. The TS X 47 series PLC of French TE company is the control host. The AXM182 axis control module and variable frequency motor form a semi-closed loop system to meet the positioning accuracy of X axis and Z axis. 
From the perspective of manufacturing, the beam has high accuracy, poor rigidity, and easy deformation. The main process: welding, heat treatment, grinding, there are deformation trends must be strictly controlled. Once a large deformation occurs, the hollow square tube is very difficult to straighten, and it is easy to produce waste. The following measures were taken during the manufacturing process:
The welding process uses carbon dioxide gas shielded welding. Welder manufacturer ESA, model LAR500, wire material HO8MnSi2A, wire diameter 1. 2mm. Using carbon dioxide gas shielded welding, no welding spatter adheres on the welding part, and the removal of slag is avoided. The surface of the welding part is beautiful and the welding quality is good. During welding, the arc burns under the compression of the air flow, the heat is concentrated, the welding heat affected zone is small, and the crack tends to be small, especially the deformation generated is small. In actual operation, in order to further control the tendency of deformation, two welders simultaneously perform welding, and the full-length twist of the beam after welding is only 3 to 4 mm, and the welding effect is very satisfactory.
The heat treatment aging process uses a 6m deep well furnace. In order to control the deformation of the beam, aging treatment must be performed to eliminate stress and deformation caused by welding. Can not use box furnace. Due to the fact that the box furnace is lying horizontally on the bottom of the furnace during the aging process, the unevenness of the bottom of the furnace will cause a concave phenomenon in the beam, and the furnace cannot be straightened, resulting in waste products. The aging process requires the beam to be vertically suspended into a pit furnace whose temperature does not exceed 250°C. The heating rate is 40°C/hour. After heating to 580°C to 620°C for 4 hours, the furnace is heated to 50°C/hour. Cooled to 250 °C baked, flat. After aging, check the full-length twist of the beam 2 ~ 3mm, to prove that the stress deformation after aging is eliminated, the effect is obvious.
Grinding is the last process of beam processing. It must achieve the requirements of straightness and parallelism. In order to improve the grinding efficiency, the process requires that the planing process prior to grinding be controlled to have a straightness and parallelism of 0.25mm/3500mm, and that the single-side grinding amount be within 0.30mm. Grinding machine manufacturers WALDRICH COBURG, model 30-15S4030. Cutting parameters: grinding wheel diameter 600mm, grinding wheel material: corundum macroporous grinding wheel, coolant: water quality coolant, v = 35m/s, S = 35m/min, T-rough = 0.02mm / double stroke, T-adjusted = 0.002mm / Double trip. Cross beam grinding can not use multi-clamping clamping method, because this method makes the heat generated in the grinding process to cause the beam to be deformed, the beam becomes wavy after grinding, straightness, parallelism can not meet the requirements. Front and rear, middle support fixtures are feasible. However, how to solve the problem of grinding heat to deform the beam is still a major problem. Grinding wheel contact cross beam grinding surface does not feed into the knife, reciprocating operation of the second, the resulting thermal deformation measured as much as 0.20mm convex, so that grinding can not go on. After one or two grinding feeds, the thermal deformation causes the grinding to stop. After the beam cools, it can continue to be ground. It takes 20 hours for a beam to complete. The use of 0.35mm depth and 40mm wide grooves on the ground surface is an effective way to reduce hot deformation. The water in the tank can take away a lot of grinding heat, improve the grinding conditions, a beam can be ground in only 4 hours, improve the efficiency, check the beam after grinding linearity, parallelism in the 0.04mm/3500mm Within, fully meet the requirements.
3.2 Loosen the solution of the screw The robot in the high-speed movement, often accompanied by the phenomenon of screw loosening, affecting the accuracy of its maintenance, and even affect the normal work, we coated Loctite 242 glue on each screw, has played a good effect and successfully resolved The problem of screw loosening.