1） injectedProcess action selection:
General injection molding machine can be manually operated, semi-automatic and fully automatic operation.
Manual operation is in a production cycle, each action is achieved by the operator to switch the operation button switch. Generally, it is selected when testing the machine and adjusting the mold.
When semi-automatic operation, the machine can automatically complete the action of a working cycle, but after each production cycle, the operator must open the safety door, remove the workpiece, and then close the safety door, and the machine can continue the production of the next cycle.
When the injection molding machine is fully automatic, it can automatically enter the next working cycle after completing the action of one working cycle. In the normal continuous working process without stopping for control and adjustment.
In normal production, semi-automatic or fully automatic operation is generally selected. At the beginning of the operation, the mode of operation (manual, semi-automatic or fully automatic) should be selected according to the production needs, and the manual, semi-automatic or fully automatic switch should be changed accordingly.
2） Pre-plastic action selection
According to whether the injection seat is backward before and after the pre-plastic feeding,That is, whether the nozzle leaves the mold,Injection molding machines generally have three options.（1）Fixed feeding: The nozzle is always attached to the mold before and after premolding, and the injection seat does not move.（2）Pre-feeding: the nozzle is pressed against the mold for pre-plastic feeding. After the pre-plastic is completed, the injection seat is retreated and the nozzle leaves the mold. The purpose of choosing this method is to use the mold injection hole to help the nozzle during pre-molding to avoid melting material flowing out of the nozzle when the back pressure is high, and to avoid heat transfer caused by long-term contact between the nozzle and the mold after pre-molding, affecting the relative stability of their respective temperatures.（3）Post-feeding: After the injection is completed, the injection seat is retreated, the nozzle leaves the mold and then pre-molded, and the injection seat is advanced after the pre-molded. This action is suitable for plastics with a particularly narrow molding temperature. Due to the short contact time between the nozzle and the mold, the heat loss is avoided, and the solidification of the molten material in the nozzle hole is also avoided.
When the injection is finished and the cooling timer is timed, the pre-molding action begins. The screw rotation melts the plastic and pushes it to the front of the screw head. Due to the role of the check valve played by the stop ring at the front end of the screw, the molten plastic accumulates in the front end of the barrel, forcing the screw back. When the screw back to the predetermined position (this position is determined by the travel switch or electronic ruler, control the distance of the screw back, to achieve quantitative feeding), pre-plastic stop, screw stop rotation. This is followed by the ejection (also called extraction) action, ejection is the screw for a small amount of axial retreat, this action can make the pressure gathered at the nozzle to be relieved, overcome due to the imbalance of the pressure inside and outside the barrel caused by the "salivation" phenomenon. If the ejection is not required, the ejection stop switch should be adjusted to the appropriate position (using the electronic ruler to set the last section of the storage position and the ejection position to be the same), so that the same moment the pre-plastic stop switch is pressed, the ejection stop switch is also pressed. When the screw makes the ejection action to step back to the press stop switch, the ejection stops. Then the seat began to recede. When the seat backs up to the pressure stop switch, the seat stops backing up. If the fixed feeding method is used, the position of the travel switch should be adjusted.
Generally, the fixed charging method is used to save the operation time and speed up the production cycle.
3 ）Injection pressure selection
The injection pressure of the injection molding machine is adjusted by the proportional pressure regulator. In the case of adjusting the pressure, the level of the injection pressure before and after is controlled by the conversion of high pressure and low pressure oil circuit.
Ordinary injection molding machines above medium size have three pressure options, namely, high pressure, low pressure and first high pressure after low pressure.
4 ）Choice of injection speed
The injection speed of the injection molding machine is adjusted by the proportional flow valve, and sometimes a large flow pump and a small flow pump run at the same time in the hydraulic system. When the oil circuit is connected to a large flow, the injection molding machine to achieve fast opening and closing mold, rapid injection, rapid storage, etc., when the hydraulic oil circuit only provides a small flow, the various actions of the injection molding machine will be slow.
5 ）Ejection form of choice
Injection molding machine ejecting form has two kinds of mechanical ejecting and hydraulic ejecting,Some are also equipped with pneumatic ejection systems,Ejection times are provided in two types: single and multiple. The ejection action can be manual or automatic.
6 ）Temperature control
Temperature measuring thermocouple is used as temperature measuring element, temperature measuring millivoltmeter is used as temperature control device, and the current of barrel and mold heating ring is directed on and off, and the temperature of barrel and mold is fixed selectively.
7 ）Mode closing control
The mold closing is a huge mechanical thrust to close the mold to resist the high pressure injection of molten plastic and fill the mold during the injection process and the huge opening force of the mold.
The mold closing structure of injection molding machine has full hydraulic type and mechanical connecting rod type. No matter what kind of structure form, the final connecting rod is completely straightened to implement the clamping force. The straightening process of the connecting rod is the process of stretching the movable plate and the tail plate, and also the process of stretching the four tie rods.
The size of the clamping force can be known from the maximum value of the oil pressure gauge rising at the moment of the clamping die, the maximum value of the oil pressure gauge is high when the clamping force is large, and the other is low. The smaller injection molding machine does not have a clamping oil pressure gauge, and it is necessary to judge whether the mold is really tight according to the straightening of the connecting rod. If the connecting rod is easily extended when the mold is closed by an injection molding machine, or“"A little bit" fails to straighten, or a pair of connecting rods is not fully straightened, there will be expansion mold when injection molding, and the parts will appear flash or other problems.
8 ）Open mode control
When the molten plastic is injected into the mold cavity and cooled down,, is followed by the mold opening action , Take out the product. The mold opening process is also divided into three stages. In the first stage, the mold is opened slowly to prevent the parts from tearing in the mold cavity. The second stage is rapid mold opening to shorten the mold opening time. The third stage of slow mold opening to reduce the impact and vibration caused by mold opening inertia
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