paul boscott

Extrusion Press Operating Cycle

extrusion press
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  The Press cycle as I remember it starting from the billet at extrusion temperature.

Billet up to temperature signal from Banyard induction heater.

A green indicator light is illuminated in the control desk and the press driver presses the start cycle button.

If the billet transfer arm limit switch indicating the transfer arm is full back is made the billet stop / thermocouple carrier retracts.

The furnace output conveyer starts and the furnace billet pusher moves forward until the billet clear of billet lotushomeing trough limit switch is made it the returns to its fully back position and the billet lotushomeer rotates the billet on loader cycle the up to temperature billet moves forward onto the exit conveyor till the billet exit end stop limit switch is made this stops the exit conveyor starts the billet transfer if the billet loaders are in accept position and causes the billet stop to return to the billet stop position the billet stop in the forward position causes the billet furnace to switch on the heat the billet to the set temprature.

If billet on loaders and pad on first loader and container and main ram in billet load position the both billet loaders rise to hold billet on extrude centre line (the billet loaders are mechanically interlocked so that loader 2 must rise with loader 1)

when loader 1 on centre line limit switch made the main ram is pushed forward with the dump valve open by the side rams also retracts the billet transfer arm to the load position.

When the main ram position l/s indication the ram at loader 1 drop the loader 1 drops if the loader 1 l/s down is closed the main ram continues to the loader 2 down l/s loader 2 drops (at this point both the billet and the pad are in the container) if either of the die slide in position l/s are made and the shear up l/s is made the container closes when the container closed l/s is closed the containers valve goes into the lock position and the valve opening the close container is opened to the container seal pump and is pressurised to xxx .

The main ram continues forward on the side rams until the pressure in the side rams reaches xxx p.s.i. The reaching of this pressure closes the dump valve an puts the main pumps to the main ram the pump stroke for volume/pressure is then under control of the press driver.

The press is now in extrude mode and the press drive controls the main pumps attaing the correct extrusion speed this is the rate that the die will run at.

The extrusion continues until the extrusion stop (set by the press driver) l/s is reached or the main ram fully extended l/s is made.

This causes the container seal pump to stop the main pumps stroke to go to neutral and the container to open (it opens with the main ram still in the fully forward position) when the container open past the end of the pad the dump valve opens and main ram starts to return to the billet load l/s the container then follows the ram back to the container fully open position.

When the container fully open l/s is made and the pad lift l/s fully down is closed the scrap cut off shear is sent down to the shear down l/s a dwell and the shear is returned to the shear up position the press driver must press a button to confirm the scrap is not stuck to the shear and is in the pad lift.

The container the closes to the billet load position if a single cycle then this is its end.

If in continues cycle the billet up to temperature signal initiates the billet to go through the cycle to be in the billet loader so that when the container and main ram are in the billet loaders to centre line they will There is the facility for the press driver to delay the billet furnace start so that the heated billet just reaches the loaders as the main ram returns this is an economy and speeds up the total press cycle.

If there has been a problem and the billet is not at extrusion temperature the driver can push the billet through the press without a die in place. It is also possible for authorised maintenance personnel to have full manual control of all functions without any interlocks to extract the machine from any unforeseen condition.

paul boscott