What Is The Ejection Cylinder of The Four-Column Hydraulic Press Machine

Why do the four-column hydraulic press machine have an ejection cylinder? If you look closely, you will find that four-column hydraulic press machine has an ejection cylinder. This is because many times when we have processed a product that requires a part to pull the product out of the mold, it is necessary to install the ejection cylinder.

What Is an Ejection Cylinder?

The four-column hydraulic press machine is a versatile piece of industrial equipment used in a wide range of applications, from forming metal parts to molding materials. One critical component of this machine is the ejection cylinder, which plays a key role in the process of workpiece handling after the pressing operation. In this blog, we’ll explore what the ejection cylinder is, how it works, and why it’s so important for the efficient operation of hydraulic press machines.

The ejection cylinder is a hydraulically operated component located beneath the machine's lower worktable. Its primary purpose is to eject the formed workpiece from the mold or die after the pressing process is complete. While the press exerts downward force to shape or form materials, the ejection cylinder exerts upward force to release the finished part, ensuring smooth workflow and preventing damage to the material or tooling.

Functions of the Ejection Cylinder

The function of the four-column hydraulic press machine ejection cylinder is very simple. In general, it is used for mold stripping. However, the price of a four-column hydraulic press machine equipped with an ejection cylinder is more expensive than that of a conventional four-column hydraulic press machine. Because the cylinder is a relatively important component on a four-column hydraulic press machine, adding a cylinder is costly.

● Workpiece Ejection After the pressing cycle, materials that have been molded, punched, or formed can sometimes remain stuck in the die due to the pressure applied during the operation. The ejection cylinder ensures the workpiece is gently pushed out of the mold or die cavity, ready for the next process step or for collection. This automatic removal enhances productivity by eliminating the need for manual intervention.

● Counterpressure in Forming Operations In processes like deep drawing, where metal sheets are stretched into a desired shape, the ejection cylinder provides counterpressure. This is crucial to control the flow of the material into the mold, preventing defects like wrinkles or tears. The upward force from the ejection cylinder helps balance the pressure applied from above, ensuring that the material is evenly formed.

●Assistance with Part Removal When certain materials are pressed, especially in high-pressure operations, they may adhere tightly to the tooling or mold. The ejection cylinder helps dislodge the workpiece without damaging it, reducing the risk of bending, warping, or material defects. This is especially important in precision applications, where even minor imperfections could lead to costly rework or waste.

● Support for Multi-Step Forming Processes In some complex forming operations, the ejection cylinder is used in multi-stage forming, where a part needs to be repositioned or re-aligned between different stages of the process. By controlling the movement of the workpiece, the ejection cylinder allows the press to perform multiple actions on a single part without manual intervention, increasing efficiency and precision.

How the Ejection Cylinder Works

The first step of the working process of the ejection cylinder is the ejection of the workpiece. The specific realization is that when the main cylinder returns to the movement, the top button is pressed, and the corresponding three electromagnets are energized, and two of the cartridge valves are opened, two of the hydraulic oil enters the lower chamber of the ejection cylinder through the valve insertion valve, and the oil in the upper chamber flows back to the oil tank through the valve, and the workpiece is ejected. The second step is to retract the ejection cylinder, first press the retract button, the electromagnet loses power, the other electromagnets are energized, the cartridge valve is opened, the hydraulic oil enters the upper chamber of the ejecting cylinder through the valve, and the oil in the lower chamber passes through the valve. The valve flows back to the tank and ejects the cylinder back. When these steps are completed, the next step is started and a circulation system is formed to maintain the continuous movement of the four-column hydraulic press machine.

1. Pressing Phase: The main hydraulic ram of the press exerts force on the material to shape or form it.

2. Ejection Phase: Once the pressing is complete, the ejection cylinder activates, pushing the finished workpiece out of the mold or die cavity. The cylinder’s hydraulic fluid pressure drives the piston upward to remove the part smoothly and efficiently.

3. Resetting for Next Cycle: After the part is ejected, the ejection cylinder retracts to its original position, ready for the next pressing cycle.

In contrast, the movement process of the four-column hydraulic press machine master cylinder is more complicated and the steps are more, but the working process of the ejection cylinder is very simple, two steps only, and the two can be said to be closely related.