Transfer presses are mainly used for sheet metal forming in a medium to high-volume, labor-free, and automated production environment. Multiple dies are used during the pressing operation as a complete system. Every die in the system is responsible for adding a new dimensional feature to the workpiece until the intended final shape is complete.
In short, a transfer press is actually a combination of a series of forming processes. In the past, it took individual presses to carry out a complex design. The workpieces had to move from one station to another and the transfer was done manually. As technology has improved over the years, manual transfer was replaced by automated systems, hence the existence of the modern-day transfer press.
Servo Press TSD 1600, Schuler Group
The movement of the workpiece from one operation to the next is performed automatically. Within the system, there are a number of forming processes, each conducting the designed task to shape the workpieces. Upon opening the built-in transfer mechanism, the workpiece in the line transfers between operations. Transfer presses typically incorporate one of two mechanisms, tri-axis transfer or crossbar transfer.
The motion of tri-axis transfer is characterized by the 3-axis movement produced by the part manipulators in the machine. On the downstroke, the work-holding system lowers the workpieces and then retracts to leave the pieces on the machine. The system in the retracted state cycles back to align itself to the next batch.
As the press rises to the top of its stroke, the manipulators approach, pick up the workpieces, and transfer them to the next operation. After dropping the workpieces onto the next operation, they are clamped again for the next downstroke. The three axes are up-down, in-out, and forward-back. The following video shows the operation of a tri-axis transfer system in 3D animation.
Transfer Press Simulation, masterhansen
Crossbar transfer is also called dual-axis transfer. The in-out motion (picking up the workpieces) is limited by an automation bar spanning the space of the die. This crossbar picks the workpieces up from above and places them into position at the next station. It usually clamps the parts with suction cups. During the downstroke cycle, the crossbar dwells between two operations. In the video below, you can see the press transfer parts with suction cups.
Ford Retrofits Transfer Press, Schuler Group
One of the benefits is that this process incurs little tooling costs. Another advantage is its versatility. It can either be a multiple-die arrangement for sequential stations or a single die by itself. It allows primary press operations (such as drilling, piercing, cut-out, etc.) and eliminates the extra expenses that may be involved in secondary operations.
Moreover, it is ideal for situations where the parts have to be removed from the metal strip to enable operations to proceed in a free state. The operation of the transfer press starts with feeding the metal strip into the first station. The blank for the part is cut from the strip and then mechanically transferred through different forming stations. All components are moved at the same time. See the video down below to see how the blank and strip are divided during operation.
Bias Multi Servo Transfer Press, Bias Makina/Machinery
Following the above, with a great many benefits comes a wide myriad of applications. Some of the major circumstances where you will see a transfer press operate include:
Transfer of large parts between several presses
Processing of and structural components.
Furthermore, automotive, lawn and garden, locomotive, medical, electronic, heavy trucking, agriculture, and recreational vehicles also make use of transfer presses. The materials that the machine frequently processes include stainless steel, aluminum, titanium, copper, brass, noble metals, rubber, and plastic.
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