Plastic molding processing equipment is developed on the basis of rubber machinery and metal die-casting machines. Since the emergence of polymer injection molding technology and simple molding equipment in the 1870s, as an industry, it did not achieve rapid development until the 1930s. Plastic molding processing equipment was gradually commercialized, and injection molding and extrusion molding have become industrialized. The processing method. Blow molding is the third largest plastic molding method after injection and extrusion, and it is also the fastest growing plastic molding method.
1. The molding machine is roughly divided into three main parts:
1) Electric control part:
Traditional injection molding machines use contact relays to switch various actions. They often fail due to loose contact screws and aging contacts. Usually, they should be replaced after one million times of use to ensure the stability of the electronic control. In particular, environmental factors such as dust adhesion and humid air will also affect the machine's operation.
Modern injection machines use contactless integrated circuits, which greatly reduces the connection of wires, significantly improves the undesirable phenomena caused by the wires, and improves the stability.
2) Institutional part:
The part of the mechanism should be regularly maintained and lubricated to reduce the coefficient of friction and reduce wear. The nuts and locking screws on the head plate should be checked regularly to prevent the elder pillar from breaking due to uneven force.
The mold thickness adjustment mechanism should regularly check whether the large gear or chain of the drive shaft is offset or slack. Whether the screw of the pressure plate on the gear is loose, whether the lubricating grease is enough, etc.
3) Hydraulic part:
In the hydraulic system, attention should be paid to the cleanliness of the hydraulic oil to maintain the quality of the hydraulic oil. The stable and high-quality hydraulic oil should be used. In addition to regular replacement, its working temperature should be properly controlled below 50C to avoid deterioration. And affect the stability of hydraulic action.
When the injection molding machine is in operation, the controller will sound an alarm when there is any abnormality in the system, and a line of warning messages will appear at the bottom of the camp screen, as shown below
Failure problem analysis and solutions
The cause of machine failure is often caused by improper operation and setting, and easy troubleshooting can be done through analysis.
Adjustment of clamping force and low pressure protection
step:
1. The clamping high pressure is set to 135bar, 10%; the low pressure speed is set to 20%, the low pressure position is set to 100mm; the low pressure time is set to 5 seconds.
2. Use the advance and retreat of the mold adjustment to establish the clamping force; the maximum value of the pressure gauge rising when the system pressure gauge is closing the mold is subject to the maximum value, and you can refer to the clamping force hydraulic pressure comparison table.
3. After opening the mold, set the low pressure position to zero.
4. Press the closing mold until the mold is in contact and release immediately. At this time, the movable mold position is assumed to be "X", and the low pressure position is set to "X+1" mm.
5. Then set the low-voltage protection width: the low-voltage protection width is the distance from low speed to low pressure.
6. Set the low-voltage protection time to usually 1.2 seconds