150 Ton Injection Molding Machine

The ZOWEITE® 150 ton injection molding machine is an injection molding machine with a clamping force of 1500KN. The 150 ton injection molding machine made in China can make many plastic products, such as: PVC/PPR pipe fittings, electronic accessories, mobile phone cases, LED lens lights and other products. The parameter table of the 150 ton injection molding machine is shown in the figure below:

What is the working cycle of the 150 ton injection molding machine?

1. Lock the mold: the template quickly contacts the fixed template (including slow-fast-slow speed), and after confirming that there is no foreign matter, the system turns to high pressure, and the template is locked (maintain the pressure in the cylinder)

2. The shooting table moves forward: the shooting table advances to the specified position (nozzle and mold are close to each other)

3. Injection: The screw can be set to inject the molten material at the front end of the barrel into the mold cavity at multiple speeds, pressures and strokes

4. Cooling and pressure maintaining: According to the setting of various pressures and time periods, the pressure of the barrel is maintained, and the cavity is cooled and formed

5. Cooling and pre-molding: The products in the mold cavity continue to cool, and the hydraulic motor drives the screw to rotate to push the plastic particles forward. The screw retreats under the control of the set back pressure. When the screw retreats to the predetermined position, the screw stops rotating and injects The oil cylinder is released according to the setting, and the expected end

6. The shooting table retreats: after the pre-plasticization, the shooting table retreats to the designated position

7. Mold opening: the template moves back to the original position (including slow-fast-slow)

8. Ejection: the thimble ejects the product

What is the principle of PID temperature adjustment for ZOWEITE® 150 ton injection molding machine?

1.Proportional operation refers to the proportional relationship between output control quantity and deviation. The larger the setting value of the proportional parameter P, the lower the control sensitivity, and the smaller the setting value, the higher the control sensitivity. For example, if the proportional parameter P is set to 4%, it means that when the measured value deviates from the given value by 4%, the output control The amount changes 100%. The purpose of the integral operation is to eliminate the deviation. As long as there is a deviation, the integral action will move the control quantity in the direction of eliminating the deviation. The integral time is a unit that expresses the intensity of integral action. The shorter the set integral time, the stronger the integral action. For example, when the integral time is set to 240 seconds, it means that for a fixed deviation, it takes 240 seconds for the output of the integral action to reach the same output as the proportional action.

2. Proportional action and integral action are corrective actions for the control results, and the response is slower. The differential action is supplemented in order to eliminate its shortcomings. The derivative action corrects the output according to the speed generated by the deviation, so that the control process can be restored to the original control state as soon as possible. The derivative time is a unit indicating the strength of the derivative action. The longer the derivative time set by the instrument, the derivative action will be used. The stronger the correction.

3.The PID module is very simple and precise, only need to set 4 parameters to perform precise temperature control:

(1) Temperature setting

(2) P value

(3) I value

(4) D value

The temperature control accuracy of the PID module is mainly affected by these three parameters, P/I/D. Among them, P stands for proportion, I stands for integral, and D stands for differential.

Proportional operation (P): Proportional control is to establish an operation related to the set value (SV), and calculate the calculated value (control output) based on the deviation. If the current value (PV) is small, the calculated value is 100%. If the current value is in the proportional band, the calculated value is calculated according to the deviation ratio and gradually decreases until the SV and PV match (that is, until the deviation is 0), then the calculated value returns to the previous value. If there is a static error (participation deviation), the method of reducing P can be used to reduce the residual deviation. If P is too small, oscillations will occur instead.

4. Integral calculation (I)

Combining integral and proportional operation, the static error can be reduced as the adjustment time continues. The integral intensity is expressed by the integral time, which is equivalent to the time required from the integral operation value to the proportional operation value under the influence of the step deviation. The smaller the integration time, the stronger the correction time of the integration operation. However, if the integral time value is too small, the correction effect is too strong and there will be turbulence.

Calculus operation (D)

Both proportional and integral calculations correct the control results, so response delays will inevitably occur. Differential operation can make up for these shortcomings. In a sudden disturbance response, the differential operation provides a large operation value to restore the original state. Differential operation adopts an operation value that is proportional to the deviation change rate (differential coefficient) to correct the control. The intensity of the differential operation is represented by the differential time, which is equivalent to the time required for the differential operation value to reach the effect of the proportional operation value under the influence of the step deviation. The larger the derivative time value, the stronger the correction intensity of the derivative operation.

To sum up, we set the proportional value to 11, the integral value to 80, and the differential value to 40. The temperature sampled by the platinum resistor is sent to the PID module. After 2-3 action cycles, the temperature curve tends to Stable, temperature control can reach the standard of ±1℃.