HVCU and Adiabatic Softening
High velocity impact
Hydropulsor's turn-key press systems include all of the components needed to handle, straighten, cut, and discharge quality blanks or billets from bar or coil; however, the essential components of HVCU (high velocity impact cutting) include a set of closed dies (one stationary and one moveable), a ram, and a source of controlled kinetic energy sufficient to drive the ram into the moveable die and separate the metal adiabatically. This mechanism is common to all forms of "adiabatic" cut off.
One cycle, one cut
STEP 1: Energy is Released The ram starts the impact sequence when a precisely measured length of wire or bar is fed into the cut position.
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STEP 2: Energy is Transferred Impact energy is transferred to the moveable die and adiabatic softening occurs in the metal between the two dies.
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STEP 3: Mechanism is Reset After the cut , the ram and tool move back to the initial position and a new length of metal is fed through the dies.
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Adiabatic Softening
Adiabatic softening is often referred to as the "adiabatic phenomenon" because of the high quality of the cuts at extreme production rates. In just milliseconds, energy is concentrated and confined to the exceptionally narrow plane between the two dies. In this plane, known as the "adiabatic zone", energy is converted into heat faster than the material being cut can dissipate it. This heat creates controlled plastic deformation and separates the material so quickly that strain hardening is confined to a depth of less than 0.04 mm.
In a high velocity impact press, the speed at which the moveable die travels can vary and should be set according to the cross section and hardness of the material being cut. If the energy is insufficient to create adiabatic shearing, the cut will not be completed or the cut will be rough. If the energy is excessive (not sufficiently controlled), it can transfer into the tooling and surrounding equipment and can damage both.
Early machine developers classified high velocity cutoff equipment as being adiabatic based on the speed of the ram, stating inaccurately that the speed of the ram must be at least 6 MPS to be classified as adiabatic. Today, we know ram speed alone cannot produce adiabatic softening in metal; and it is now obvious that adiabatic softening is the result of applied kinetic energy. It is more accurately measured by the speed of the moveable die upon contact with the material being cut, and adiabatic softening is the result of that applied energy.
Learning to Manage Energy
Hydropulsor became the world's leading manufacturer of high velocity impact equipment when our engineers developed a means of supplying sufficient energy that could be controlled incrementally by the equipment operator and precision tooling that could withstand the impact of the ram.
Today, Hydropulsor is recognized as the proven world leader in high velocity impact technology because we dedicated years of research in learning to manage this energy to make it work for you.