Control method with substitution mode ejection to pressure-relaining changeover point

Abstract

A die cavity pressure sensor is set in the forming die of ejection forming machine, a rubber-jetting screw rod position sensor is mounted on the rubber-jetting screw rod, in the power of starting ejection to switching to retain pressure the substitution mode control method is always in starting state, in which, after the signal P1 of die cavity pressure sensor and S1 rubber-jetting screw rod position sensor are picked up, a grey-level predictive mathematical model is used to respectively estimate next point P2 and S2 by using two points of every signal, and they are their actual measured values are subtrated to obtain precitive residual quantities P3 and S3, then the time sequence curves formed by using P3 and S3 can be used to find out the die cavity pressure predictive residual quantitypeak value P4 and screw rod position predictive residual quantity peak value S4.

Description

technical field [0001] The present invention is a method for controlling the switching point from injection to holding pressure with an alternative mode, which is applied to the determination of the switching timing from the speed-controlled injection stage to the pressure-controlled holding stage of the injection molding machine in the molding process, and if one of them When one group is set as the main switching reference, the other group enters the statistical learning mode, and if one group fails, this control method can automatically lock to a more stable group for switching point control. Background technique [0002] The injection molding method is a periodic process technology, and its steps are roughly divided into the mold closing process (Clamping), the injection process (Injection), the holding and plasticizing process (Holding and Plasticizing), the cooling and mold opening ejection process (Cooling and Ejection) ), the injection molding machine is controlled b...

AI Technical Summary

Problems solved by technology

Both are currently standard equipment for injection molding machines, but their results are easily affected by interference such as oil temperature fluctuations, mechanical movement errors, and plastic unevenness, resulting in large errors, resulting in too early or delayed switching timing; The third switching method is the fixed pressure switching method. For the injection molding machine driven by hydraulic pressure, there are three modes of switching methods: hydraulic pressure, nozzle pressure and mold cavity pressure, but this fixed pressure switching method is still often used. The phenomenon of poor switching occurs; the fourth is the switching method using the cavity pressure to calculate the filling volume saturation point. Although the fuzzy control theory is used for its control law, it is more robust, but it is still affected by the position of the pressure sensor and the special model. Affected by the waveform characteristics of the cave pressure

[0006] If the above four methods of injection switching and holding pressure are switched too early, the Figure 4 As shown, often make the product undersized or dented; while delay switching is as Figure 5 As shown, it is often accompanied by the risk of the mold cavity being highly squeezed. In addition to the adverse effects on the size and burr, it may also cause the main cause of the deformation of the mold cavity edge and the overload of the clamping unit, which in turn has a permanent impact on the guide post of the injection machine. damage, so it is practically impossible to achieve consistent quality requirements stably

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