How to reduce the production error of injection molding machine manipulator
At present, many machinery manufacturers are choosing the injection molding machine manipulator as the main production mode, but the use of automatic manipulator in production can greatly improve the production efficiency and output of products and reduce the production cost of products. Whether the injection molding machine manipulator can work accurately in production is actually a three-dimensional positioning problem, It is a combination of several linear and angular positioning. In many more general cases, a single value may be the main. The factors affecting the positioning error of single linear or angular quantity are as follows:
1. Positioning mode – different positioning modes have different influencing factors. For example, when the mechanical stop is positioned, the positioning accuracy is related to the stiffness of the stop and the speed when touching the stop.
2. Positioning speed – positioning speed has a great impact on positioning accuracy. This is because the energy of the moving parts that must be dissipated is different when the positioning speed is different. Generally, in order to reduce the positioning error, the positioning speed should be reasonably controlled, such as improving the buffer performance and buffer efficiency of the buffer device, and controlling the driving system to decelerate the moving parts in time.
3. Accuracy – the manufacturing accuracy and installation speed regulation accuracy of the manipulator have a direct impact on the positioning accuracy.
4. Stiffness – when the structural stiffness and contact stiffness of the manipulator are low, the positioning accuracy is generally low because it is easy to produce vibration.
Weight of moving parts – the weight of moving parts includes the weight of the manipulator itself and the weight of the grasped object. The change of the weight of moving parts has a great impact on the positioning accuracy. Generally, when the weight of moving parts increases, the positioning accuracy decreases. Therefore, the design should not only reduce the weight of the moving parts themselves, but also consider the influence of the change of grasping weight during work.
6. Driving source – the pressure fluctuation of hydraulic pressure and air pressure and the fluctuation of voltage, oil temperature and air temperature will affect the repeated positioning accuracy of the manipulator. Therefore, take necessary measures to stabilize the pressure and adjust the oil temperature. If the accumulator is used to stabilize the oil pressure, the heater or cooler is used to control the oil temperature. At low speed, the temperature and pressure compensation flow control valve is used to control.
7. Control system – the position control accuracy of switch control, electro-hydraulic proportional control and servo control is different. This is not only because the accuracy and sensitivity of various control elements are different, but also related to the presence or absence of position feedback device.
