Each mechanical power press must be looked at as an individual
system. This system consists of, but is not limited to, the
frame, all mechanical parts, clutch and brake assemblies,
electrical or electronic systems, hydraulic systems, pneumatic
systems, tooling or dies (present and future), tool or die
setup, safeguarding, material handling, size or configuration
of piecepart, and production requirements.
It is essential that presses and other machinery be
thoroughly inspected and that all mechanical, electrical,
pneumatic, and hydraulic components and systems, including all
collateral equipment, be in first-class operating condition
before any equipment is installed. A maintenance and
inspection program must be established and implemented to keep
machines in first-class condition. This program should include
regular periodic inspections of each machine to ensure that,
among other things, (i) the clutch and brake mechanism,
mechanical linkages, and air counterbalances are operating and
used properly; (ii) there is no dirt or water in the air
lines; and (iii) the machine is operating at its proper speed
(RPM or SPM). Any part of the machine that is worn, damaged or
not operating correctly should immediately be replaced or
repaired before the machine is used.
Other safety considerations include:
A press system requires the proper disconnect switch, motor
starter, transformer for reducing the voltage to 120 volts or less,
and air lockout valve.
Mechanical power-transmission apparatus include components on a
machine or auxiliary equipment including shafts, crankshafts, splines, pulleys, sprockets, rolls, flywheels, gears, and couplings.
These components can create hazards to personnel who work on or
around the machines. They must be covered in accordance with 29 CFR 1910.219 Subpart
O and ANSI B15.1. All apparatus that creates a
hazard up to 7' above the floor or platform must be guarded
(covered). This is usually done by the user, either by adding to
existing guards or by contacting a local sheet metal fabricator to
make a new cover.
Auxiliary safeguarding is used for additional protection from
injuries for all personnel in the machine area. It is used in
conjunction with primary safeguarding devices. Auxiliary
safeguarding also involves the guarding of other components or
hazardous openings on machines. One of these hazards is created by
auxiliary feeding equipment used with some power presses. Auxiliary
equipment includes various types of feeds, shuttles, magazines,
stackers, indexing tables, straighteners, reels, cradles, recoilers,
scrap choppers, iron hands, robots, etc.
Auxiliary safeguards include such items as point-of-operation
side barriers when light curtains are used, pressure-sensitive floor
mats, workpiece tables or horizontal light curtains. An additional
set of light curtains can be used horizontally to prevent an
operator or other persons from standing between the vertical plane
of light and the point-of-operation hazard. It is important to
remember that light curtains can be used only on part revolution
The two most commonly used safeguards for presses
equipped with automatic feeds are guards and presence
sensing devices (light curtains). When considering either of
these safeguards, arrange them to protect the point of operation as
well as the feed. This may require the guard to extend to the right
or left of the bolster on OBI presses. If a scrap chopper is
furnished, the guarding must also be extended to safeguard it. If a
feed and scrap chopper are on the sides of straight-sided presses,
the feed and window openings also need to be safeguarded.
When protecting operators and other employees in the press area from
hazards created by straighteners, pay-off reels, cradles, iron
hands, robots, etc., the perimeter or work envelope of this
auxiliary equipment should be safeguarded. This is usually
accomplished with guards, presence sensing devices, safety mats or a
combination of these methods.
When protecting these areas, keep in
mind that access may be required for changing coils and removing
scrap, blanks, etc.
Danger signs, used for warning, can be mounted
on the machine in a position that is readily visible to the
operator, setup person or other personnel. Hand tools are another
auxiliary safeguard often used when feeding and retrieving small
pieces or removing scrap from the die area. Hand tools by
themselves are not a point-of-operation safeguarding device.
When using a light curtain, the mounting brackets for the transmitter and
receiver may have to be modified to include safeguarding of the
feed. The light curtain's plane of light commonly protects only the
front of the press. Additional guards or mirrors are needed to
safeguard the sides and back of the machine.
When safeguarding presses equipped with shuttles, magazines, stackers, indexing
tables, etc., the previously discussed safeguards can be used. This
assumes that the press is operating in either the continuous or
automatic single stroke mode. If the press is single stroked by over
operator action, other safeguards such as two-hand
controls, pullback devices, restraints
or gate devices could be used.
The back and sides of the point of operation must always be
protected as well.