How to Set the Clamping Position of Low Pressure and High Pressure?
For the injection molding machine, its clamping process is generally divided into three or four stages, which is generally fast – slow – low pressure – high pressure. Let us explain them one by one in detail:
According to the structure of the mold, flat or having a slider, first set the pressure / speed / position during rapid clamping. Without affecting the efficiency, set the appropriate pressure/speed/position. Pay attention not only to make the mold smooth, but also to reflect the principle of rapid mold clamping.
Low pressure --- slow speed
This part is the most important. In the jog state, set the clamping pressure to 0, slow down the clamping speed, and set the position to 0. Because the machine itself has a certain pressure with which the mold will still close although the pressure setting is 0.
After the mold is closed, for the position is 0, the high pressure cannot be active. At this time, according to the position of the mold base displayed on the main panel of the controller, change the low pressure position to the data displayed on the panel.
Generally speaking, it is necessary to set the high pressure of the mold clamping according to the area of the product and the performance of the plastic. After setting the appropriate data, you need to adjust the low pressure protection again. Then, follow the previous step, and re-correct the position of the low pressure mold to ensure to be effective.
- Under the premise of ensuring the mold clamping speed, the low pressure mold clamping pressure should be set as low as possible. As long as it can reliably offset the frictional resistance of mold clamping.
- The frictional resistance between the moving platenand the column.
- The frictional resistance of the guide pin and the guide brush after the movable and fixed molds are in contact.
- The frictional resistance of the platen sliders.
- The frictional resistance of the movable platen and the supporting parts, etc.
- It is necessary to set a sufficient low pressure protection stroke (should be larger than the size of the product, or larger than the size of the upload robber if there is one).Too large a low pressure protection stroke will affect the accurate setting of the low pressure protection pressure.So the low pressure protection time setting should be reasonable and appropriate.
- After calculating the actual time of the low pressure protection starts and ends, the low pressure time should beset slightly larger than the actual time (the margin is less than 1 second to ensure that the mold clamping action signal output is stopped at the moment when there is a foreign matter).
The principle of low pressure protection: In a certain low pressure time, the computer cannot receive the high pressure signal, then the computer will determines that there is a foreign object in the mold cavity. At this time, the computer will not send out the “mold clamp” signal, then alarm and send out the “mold open” signal at the same time.
- Set the required clamping force first, and then set the high-pressure clamping pressure proportionally. The system pressure of the machine with different clamping forces is the same. Using this mechanism, the clamping force can be accurately preset by setting the high-pressure pressure.
- Set the high-pressure stroke position to be ratherlarge first. At this time, gradually reduce the high-pressure stroke position according to experience. When the high-pressure stroke cannot be raised or the machine clamping toggle cannot be straightened, then slightly raise the high-pressure stroke to make the clamping force reliable. If there is a slider in the mold, the protection position must be greater than the height of the slider guide post, and the pressure should be as small as possible.
There is an inspection standard for low-pressure mold protection. Put a 0.5-2mm thick cardboard. If the mold cannot be closed, it proves that you have set up successfully!