Machine Press
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A forming press, commonly shortened to press, is a
machine tool A machine tool is a machine for handling or machining metal or other rigid materials, usually by cutting, boring, grinding, shearing, or other forms of deformations. Machine tools employ some sort of tool that does the cutting or shaping. All ...
that changes the shape of a work-piece by the application of pressure. The operator of a forming press is known as a press-tool setter, often shortened to tool-setter. Presses can be classified according to * their mechanism:
hydraulic Hydraulics (from Greek: Υδραυλική) is a technology and applied science using engineering, chemistry, and other sciences involving the mechanical properties and use of liquids. At a very basic level, hydraulics is the liquid counte ...
,
mechanical Mechanical may refer to: Machine * Machine (mechanical), a system of mechanisms that shape the actuator input to achieve a specific application of output forces and movement * Mechanical calculator, a device used to perform the basic operations of ...
, pneumatic; * their function: forging presses, stamping presses,
press brake A press brake is a machine used for bending sheet metal and metal plate, most commonly sheet metal. It forms predetermined bends by clamping the workpiece between a matching top tool and bottom die.Parker, Dana T. ''Building Victory: Aircraft Manuf ...
s,
punch press A punch press is a type of machine press used to cut holes in material. It can be small and manually operated and hold one simple die set, or be very large, CNC operated, with a multi-station turret and hold a much larger and complex die set. D ...
, etc. * their structure, e.g. Knuckle-joint press,
screw press A screw press is a type of machine press in which the ram is driven up and down by a screw. The screw shaft can be driven by a handle or a wheel. It works by using a coarse screw to convert the rotation of the handle or drive-wheel into a small d ...
* their controllability: conventional vs. servo-presses


Shop Press

Typically consisting of a simple rectangular frame, often fabricated from C-channel or tubing, containing a
bottle jack A jack is a mechanical lifting device used to apply great forces or lift heavy loads. A mechanical jack employs a screw thread for lifting heavy equipment. A hydraulic jack uses hydraulic power. The most common form is a car jack, floor jack o ...
or hydraulic cylinder to apply pressure via a ram to a work-piece. Often used for general-purpose forming work in the auto mechanic shop, machine shop, garage or basement shops, etc. Typical shop presses are capable of applying between 1 and 30 tons pressure, depending on size and construction. Lighter-duty versions are often called
arbor press An arbor press is a small hand-operated press. It is typically used to perform smaller jobs, such as staking, riveting, installing, configuring and removing bearings and other press fit work. Punches, inserters, or other tools/dies may be add ...
es. A shop press is commonly used to press
interference fit An interference fit, also known as a pressed fit or friction fit is a form of fastening between two ''tight'' fitting mating parts that produces a joint which is held together by friction after the parts are pushed together. Depending on the am ...
parts together, such as gears onto shafts or bearings into housings.


Other presses by application

* A
press brake A press brake is a machine used for bending sheet metal and metal plate, most commonly sheet metal. It forms predetermined bends by clamping the workpiece between a matching top tool and bottom die.Parker, Dana T. ''Building Victory: Aircraft Manuf ...
is a special type of machine press that bends sheet metal into shape. A good example of the type of work a press brake can do is the back-plate of a computer case. Other examples include brackets, frame pieces and electronic enclosures. Some press brakes have
CNC Numerical control (also computer numerical control, and commonly called CNC) is the automated control of machining tools (such as drills, lathes, mills, grinders, routers and 3D printers) by means of a computer. A CNC machine processes a p ...
controls and can form parts with accuracy to a fraction of a millimeter. Bending forces can range up to 3,000 tons. * A
punch press A punch press is a type of machine press used to cut holes in material. It can be small and manually operated and hold one simple die set, or be very large, CNC operated, with a multi-station turret and hold a much larger and complex die set. D ...
is used to form holes. * A screw press is also known as a fly press. * A stamping press is a machine press used to shape or cut metal by deforming it with a
die Die, as a verb, refers to death, the cessation of life. Die may also refer to: Games * Die, singular of dice, small throwable objects used for producing random numbers Manufacturing * Die (integrated circuit), a rectangular piece of a semicondu ...
. It generally consists of a press frame, a bolster plate, and a ram. * Capping presses form caps from rolls of
aluminium Aluminium (aluminum in American and Canadian English) is a chemical element with the symbol Al and atomic number 13. Aluminium has a density lower than those of other common metals, at approximately one third that of steel. I ...
foil at up to 660 per minute.


An example of peculiar press control: servo-press

A servomechanism press, also known as a ''servo press'' or an electro-press'', is a press driven by an AC servo motor. The
torque In physics and mechanics, torque is the rotational equivalent of linear force. It is also referred to as the moment of force (also abbreviated to moment). It represents the capability of a force to produce change in the rotational motion of th ...
produced is converted to a linear
force In physics, a force is an influence that can change the motion of an object. A force can cause an object with mass to change its velocity (e.g. moving from a state of rest), i.e., to accelerate. Force can also be described intuitively as a p ...
via a
ball screw A ball screw (or ballscrew) is a mechanical linear actuator that translates rotational motion to linear motion with little friction. A threaded shaft provides a helical raceway for ball bearings which act as a precision screw. As well as bein ...
. Pressure and position are controlled through a
load cell A load cell converts a force such as tension, compression, pressure, or torque into an electrical signal that can be measured and standardized. It is a force transducer. As the force applied to the load cell increases, the electrical signal change ...
and an encoder. The main advantage of a servo press is its low energy consumption; its only 10-20% of other press machines. When stamping, it's really about maximizing energy as opposed to how the machine can deliver tonnage. Up until recently, the way to increase tonnage between the die and work-piece on a mechanical press was through bigger machines with bigger motors.


Types of presses

The press style used is in direct correlation to the end product. Press types are straight-side, BG (back geared), geared, gap, OBI (open back inclinable) and OBS (open back stationary).
Hydraulic Hydraulics (from Greek: Υδραυλική) is a technology and applied science using engineering, chemistry, and other sciences involving the mechanical properties and use of liquids. At a very basic level, hydraulics is the liquid counte ...
and mechanical presses are classified by the frame the moving elements are mounted on. The most common are the gap-frame, also known as C-frame, and the straight-side press. A straight-side press has vertical columns on either side of the machine and eliminates angular
deflection Deflection or deflexion may refer to: Board games * Deflection (chess), a tactic that forces an opposing chess piece to leave a square * Khet (game), formerly ''Deflexion'', an Egyptian-themed chess-like game using lasers Mechanics * Deflection ...
. A C-frame allows easy access to the die area on three sides and require less floor space. A type of gap-frame, the OBI pivots the frame for easier scrap or part discharge. The OBS timed air blasts, devices or conveyor for scrap or part discharge.


History

Historically, metal was shaped by hand using a hammer. Later, larger hammers were constructed to press more metal at once, or to press thicker materials. Often a smith would employ a helper or apprentice to swing the hammer while the smith concentrated on positioning the work-piece. Drop hammers and
trip hammer A trip hammer, also known as a tilt hammer or helve hammer, is a massive powered hammer. Traditional uses of trip hammers include pounding, decorticating and polishing of grain in agriculture. In mining, trip hammers were used for crushing meta ...
s utilize a mechanism to lift the hammer, which then falls by gravity onto the work. In the mid 19th century, manual and rotary-cam hammers began to be replaced in industry by the steam hammer, which was first described in 1784 by James Watt, a British inventor and Mechanical Engineer who also contributed to the earliest steam engines and condensers, but not built until 1840 by British Inventor James Nasmyth. By the late 19th century, steam hammers had increased greatly in size; in 1891 the Bethlehem Iron Company made an enhancement allowing a steam hammer to deliver a 125-ton blow. Most modern machine presses typically use a combination of
electric motors An electric motor is an electrical machine that converts electrical energy into mechanical energy. Most electric motors operate through the interaction between the motor's magnetic field and electric current in a wire winding to generate forc ...
and
hydraulic Hydraulics (from Greek: Υδραυλική) is a technology and applied science using engineering, chemistry, and other sciences involving the mechanical properties and use of liquids. At a very basic level, hydraulics is the liquid counte ...
s to achieve the necessary pressure. Along with the evolution of presses came the evolution of the dies used within them.Parker, Dana T. ''Building Victory: Aircraft Manufacturing in the Los Angeles Area in World War II,'' pp. 20, 29, 48, 83, 85, 87, Cypress, California, 2013. .


Safety

Machine presses can be hazardous, so safety measures must always be taken. Bi-manual controls (controls the use of which requires both hands to be on the buttons to operate) are a very good way to prevent accidents, as are light sensors that keep the machine from working if the operator is in range of the die.


References


External links


Metal forming handbookForging Industry Association
{{Authority control * Metal forming Machine tools Articles containing video clips