In the maintenance of injection molding machines, a common issue is the inability to open the mold. This inability to open the mold is primarily categorized into three fault phenomena: no action with pressure, no action with pressure, and no action without pressure.

Pressure without action:

First, check if the display light on the mold valve output board is on. If it's on, it indicates that the computer output is normal, but there's an issue with the wiring between the computer and the mold valve. A simple way to test this is for one person to use a small multimeter to activate the mold valve while another person opens the mold. If the mold can open smoothly from the top rear, it confirms a wiring issue; re-wiring is needed (a circuit problem).

Pressure and mold actions are present, but molding is not possible.

The output board is functioning normally, and the circuit from the output board to the valve is also in good condition.

Here are four scenarios:

Firstly: The tightening screw of the mold cylinder piston is loose, causing the screw to be scraped inside the cylinder, potentially leading to the piston rod getting stuck.

Secondly, for the mechanical lock, the solution is to disconnect the mold oil tube and operate with a jack, which will not damage the machinery.

Thirdly, the inability to pull due to machine twisting (such as burnt edges from twisting).

The fourth type: Interference caused by (oil interference and circuit interference). If the valve core is jammed, and the mold opening action is required at the same time, the oil pump cannot supply the necessary pressure and flow for mold opening, of course, the mold cannot be opened either; another type of interference is circuit interference. For example, the mold opening line and the mold locking line are connected, as both the mold opening valve and the mold locking valve operate simultaneously, the pressure is around 20 kg, so the mold cannot be opened.

No pressure, no movement.

However, check if the computer output board is functioning normally, if there's pressure and speed, and if the mold valve is outputting, and if the computer homepage is displaying. In this case, we will check other actions, such as whether the injection table and seat are normal, which means this phenomenon is a single occurrence during the mold opening process. Generally, one person checks the mold opening action, while another uses a multimeter to measure the coil voltage of the mold valve, which should be around 22-30V. If so, we will temporarily remove the coil of the mold valve and initiate the mold opening action.

Due to the similar oil circuit in injection molding machines, this situation occurs in the mold opening process, as well as in other actions. The key to repairing the machine is in summarizing. From this fault, we find that repairing the machine can be both simple and complex. In short, from the four aspects of circuit, hydraulics, oil circuit, and mechanics, nothing changes.

When it comes to complexity, it's generally important to follow a troubleshooting sequence, from simple to complex, i.e., circuit, hydraulics, oil lines, and mechanics. If the inspection sequence is not appropriate, the repair process can be both laborious and time-consuming.