What To Do If The Hydraulic Clamping Pressure Of The Injection Molding Machine Fails?

With the popularization and use of full hydraulic injection molding machines, some users recently reported that the clamping pressure cannot be reached or the clamping pressure cannot be maintained. We know that the clamping force of the connecting rod machine is self-locking after being amplified by the toggle link mechanism. The clamping force will not change before the toggle link is opened, and the clamping force of the full hydraulic machine depends on the clamping cylinder. If the oil pressure drops, the clamping force of the machine will be insufficient. Several possible factors affecting the clamping pressure are summarized as follows, for reference by outside repairers and debugging personnel.

1. The clamping pressure cannot be reached

The clamping pressure input on the display screen is 200, but the clamping pressure gauge actually shows only 150bar, and the holding pressure is normal.

1. In a plastic machine without a clamping pressure relay or pressure sensor, the clamping position is controlled by the clamping time. You can first increase the clamping time on the display screen and observe whether the pressure gauge shows up.

2. Check whether the maximum pressure of the system can reach 200bar, and the pressure can be adjusted in the system pressure and flow debugging page of the display screen. If it can't be reached, it may be due to other reasons such as checking the pump source.

2. The clamping pressure cannot be maintained

1. The mold clamping pressure drop is generally caused by the internal leakage of the valve. Taking CHG128 as an example, the internal leakage of the hydraulic control check valve V15 and the superimposed hydraulic control check valve V33 on the clamping valve plate can protect the clamping Pressure has an impact. However, because the internal leakage of these two valves is small, it shows that the clamping pressure drops slowly. Most of them are stuck due to dirt. You can disassemble and wash the two valves one by one.

2. The sealing performance of the four internal circulation piston components, including the sealing of the valve core and the sealing of the seal on the piston, if leaks, it will be manifested as a rapid drop in clamping pressure. The disassembly and assembly here is very troublesome, and it is generally handled last.

3. In the old machine, the mold-clamping cylinder realizes the external circulation through the cartridge valve. The cartridge valve is normally open. When the pressure is maintained, the cartridge valve should be closed under the action of the control oil. At this time, the control oil leakage It will also open the cartridge valve, causing a drop in pressure. The control oil is pressure-maintained by the superposition hydraulic control check valve V12. The internal leakage and closing speed of V12 will affect the pressure-keeping. It shows that the clamping pressure dropped by 10-30 bar in a short time, and then remained unchanged. At this time, the return spring of V12 needs to be replaced to make it close quickly.

The pressure failure of the clamping cylinder should be analyzed from the above points, from simple to difficult, and eliminated one by one.