- Cylinder - Cylinder assembly consists of a
cylinder, piston, ram, packing, and seals. Piston diameter and oil
pressure determine the force (tonnage) that a given press can
deliver.
- Frame - The main structure of the press
containing the cylinder(s) and the working surfaces.
- Stroke Control - Stroke length can be set for
any distance within the stroke limits of the cylinder. Adjustments
include: top of stroke, pre-slowdown point, and bottom of stroke.
- Throat Clearance - The distance from the
vertical centerline of the ram to the frame member behind the bed.
This distance determines the largest diameter piece that can be
positioned with the part centerline under the center of the ram.
- Daylight - The vertical clearance from the
top of the bolster to the underside of the ram in its maximum up
position. This term sometimes is confused with the mechanical press
term "shut height". Shut height is the clearance over the
bed with the ram full down. "Daylight" describes the
maximum vertical capacity of the press.
- Bolster - A plate or structure mounted on the
bed. Hydraulic press manufacturers provide a removable bolster on
most models.
- Bed - Flat, stationary machined surface that
supports the bolster or dies.
- Dual Palm Button Controls - A common method
of actuating hydraulic presses. Both buttons must be depressed at
the same time to bring the ram down requiring the operator to use
both hands. Control circuits include non-repeat and anti-tie down
features.
- Work Height - The distance from the floor to
the top of the bolster.
- Shut Height : The distance between the bed
bolster & the raw bolster when the raw is fully extended. This
is also known as closed Height.
- Bed Cushion : A bed cushion is a commonly
required for draw tooling & is a system that applies resistance
when pushed upon. This resistance can be dynamic or statically
controlled throughout that stroke. Bed cushion have a pusher pin
plate that is located just beneath the bed bolster. The bed bolster
is provided with multiple through holes usher “ “pusher
pins” are inserted. These pins are used by the tooling to
generate resistive force as the hydraulic press raw pushes down.
Other hydraulic press terms
Blankholder - A control controlled force to hold the
edges of the blank in deep drawing operations. Similar to a die cushion.
Distance Reversal Switch - An adjustable limit
switch to set depth of stroke at which ram reverses.
Dwell Timer - An adjustable timer to set the length
of dwell at the bottom of the stroke. The timer may be used for other
functions such as timing a sequence of press movement.
Heat Exchanger - A device attached to the oil
reservoir to circulate water or air to keep oil at proper operating
temperature.
Knockout - A device to strip the part from the punch
or die.
Platen - A plate-sometimes heated-attached to a
moving or stationary press member.
Pressure Reversal Switch - An adjustable switch to
set the pressure at which ram reverses.
Dwell - Hydraulic Presses are cable of maintaining
force on the work for extended periods of time. This is typically
accomplished by using Pressure lock value or variable volume pumps that
are remotely controlled for precise & long period of Pressure
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