Press Brake Guards
Side and Rear Press Brake Guards
Side and rear press brake guards, also sometimes referred to as ‘end barriers’ or ‘press brake guards’ are a form of press brake safety that have no moving parts. They function by sectioning off certain areas of the die. They are physical barriers put into place to prevent the operator’s hands or any other objects from entering the point of contact at an area where they don’t need to be, even for operational duties.
How Does the Operator Still Do Their Job with Physical Barriers Around the Die?
Press brake guards only section off areas that extend beyond the operator’s work space. Most likely, the operator never needs to access these sectioned off areas for any reason. They only present a risk when uncovered. So, a permanent barrier is necessary.
Why is there Such a Large Area of the Die that the Operator Doesn’t Need to Use?
Dies typically are not manufactured according to the part they will be used for. As a result, many press brakes have points of contact that cover a wider area than necessary for certain jobs. These areas and other areas that must remain protected can be covered by two types of press brake guards. These types are side guards or rear guards.
Press Brake Guards
Side Guards vs Rear Guards for Press Brake Safety
The sides of the machine should protect from objects and hands. But the barriers in place there should be movable. These protect the operator from angles other than being directly in front of the die. Rear press brake guards section off the back gauge and prevent access to the rear of the area of contact. All areas of the machine must observe proper press brake safety measures, including adequate protection for those other than the primary operator.
Side and rear press brake guards are very inexpensive, simple ways to further safeguard your machine safety and ensure the well being of the press brake operator working with it directly or in its vicinity.
A press brake sheet follower or sheet lifter is a device for press brake safety that helps keep operators safe when working with large sheets of metal that may otherwise be difficult to handle. They function by way of hydraulic arms that hold the sheet while it’s being bent by lifting the sheet as the die makes contact, and then lowering after the bend has been made. They aren’t intended to be used with smaller, lighter sheets. For big, heavy sheets however, they protect the operator by allowing them to stand away from the device during operation and activate it with a foot pedal from a safe distance.
Benefits of a Press Brake Sheet Follower
When a bend is made in the metal sheet by the press, the sheet comes up rather abruptly. This creates a danger in addition to the die coming down, because the sheet can come up and make contact with the operator’s face or another part of their body. A press brake sheet follower is not only highly effective for press brake safety purposes, it also helps to limit press brake operator fatigue by supporting the weight of the sheet, thus allowing the operator to work at a steady pace more comfortably.
How a Press Brake Sheet Follower is Set Up
Press brake sheet followers get positioned in front of the machine and can be moved anywhere along the area of contact or can be moved away from the machine quite easily as they are typically on wheels. For use with RPG back gauges, sheet followers may be placed at the interior of the machine for operation.
The rising/lowering platform’s height on a sheet follower may be adjusted to accommodate different jobs and press brakes. Sheet followers may also be accompanied by a slide for easier movement along the area of contact. The slide allows the press brake sheet follower to glide along smoothly, or be moved out of the way with little effort. At the end of this slide may be a “docking” area where the device can be slid and wheeled to, two feet from the die, disconnecting it from the press brake temporarily.
The purpose of a light curtain is to protect the operator from making contact with any part of the press brake that could potentially cause harm during operation. When properly implemented, a light curtain stops the press brake abruptly before the operator can sustain any injuries. There are numerous regulations in place to ensure the effectiveness of light curtains that determine whether or not a system passes inspection. It’s essential to adhere to all of the regulations that coincide with the type of press brake system you operate. Light Curtains also make it possible to use a foot switch instead of a two hand push button station.
How A Light Curtain Provides Press Brake Safety
A light curtain is a type of presence sensing device that doesn’t reduce productivity or delay work because it uses no restraints, straps, or physical barriers. It functions by way of one or more transmitters and receivers. If the stream of light or lasers is broken and the receiver no longer detects it, the machine ceases immediately.
Many light curtains have a floating beam option, individual or multiple infrared beams may be broken by the part being formed. Some light curtains allow up to eight inches of beams to be floated.
Channel Select or Canceling
Beam canceling is an option on some light curtains. Canceling beams allows you to blank out or ignore a given number of the beams. It is a very useful option if used properly and safely. Some light curtains can be programmed to selectively cancel a given number of beams during the forming operation.
The Advantages of a Light Curtain
Light curtains can be highly effective if used properly. Although the initial cost of a light curtain press brake safety system may be much higher than using restraints, physical barriers, and two-handed manual start systems; they allow the production process to operate at full capacity. The savings in manpower time and production speed more than balance the initial cost of a light curtain system.
Functions Must Be Programmed According to OSHA
OSHA stipulates exactly how presence sensing devices of all types must be used in order to pass minimum safety regulations. OSHA standards and regulations include adequate safe distance for the machine they’re used with, software programming, and more.
Press Brake Two Hand Control
A press brake two hand control device is an effective method of protecting the operator’s hands from entering the point of contact and potentially causing injury. It works by forcing the operator to use both hands to initiate the stroke by having two buttons, one on each side of the operator, that must be held down simultaneously in order for the press brake to function. If one button ceases to be pressed, the machine abruptly stops.
Single Stroke Mode
If the machine is running on single stroke mode, the operator must simply hold down both buttons on the press brake two hand control until the stroke is complete. For sequence mode, the operator must hold down both press brake two hand control buttons until the die reaches its designated distance (typically 6 mm depending on specific settings and the size of the workpiece), and then set the workpiece into position. A foot pedal can then be used to complete the process of the stroke.
Press Brake Two Hand Control Instead of a Foot Pedal
A space of 6 mm is too small for the human hand to fit through, thus a foot pedal is adequate for press brake safety for completing the second step. A press brake two hand control device may be used instead of a foot pedal to complete the process of bending the work piece.
Press Brake Two Hand Control Advantages
Press brake two hand control systems are advantageous because they do not require the use of a physical strap on the press brake operator, they’re relatively inexpensive compared to laser systems, and they are effective at protecting workers when used correctly. A downside to this method of press brake safety is that production may be slower than with a light curtain or laser system.
Foot Pedal With a Press Brake Two Hand Control
The use of a foot pedal to finalize the stroke may make the process faster than only using two hand controls for a machine operating in sequence mode depending on the positioning of the press brake safety equipment and the nature of the task. Check OSHA standards for two hand control devices to see how they must be used to ensure sufficient worker protection for your press brake system.
Laser Beam Device
A laser beam device is a highly efficient type of presence sensing device for press brake safety. Laser beam devices are the most modern and eventually cost effective way to fully protect the operator while allowing productivity to flow at maximum capacity. They don’t restrict or hamper the press brake or the press brake operator in any way as long as nothing comes in contact with the stream of laser beams directly in front of and behind the die.
How Does a Laser Beam Device Work?
A stream of laser beams is created by a transmitter on one side and a receiver on other. The stream can vary in length, but typically only covers key areas of risk while other areas that are not dangerous but may be within the lasers’ range can be ‘muted’. Laser beam device systems also incorporate the use of a foot pedal.
Laser Beam Device Object Detection
If the laser beam device detects an object entering the area of contact by stream disruption, the die immediately gets retracted before anyone can possibly be injured. Since there is a beam that passes between the punch and the die, the operator remains protected up to a matter of millimeters.
Laser beams can be used for press brake safety either in parallel rows or in a grid. A grid works the same as a row, detecting disruptions in the stream and immediately ceasing machine operation. Special modes can be programmed in the laser beam device’s software that most effectively protect the operator while not impeding production rates.
Are Laser Beams and Light Curtains for Press Brake Safety the Same?
Light curtains are also presence sensing devices, but they don’t project the same kind of light. A laser beam device can perform far more accurately, allowing operators to perform tasks within very tight spaces safely.
Laser beam devices for press brake safety should be fully OSHA standards compliant when properly installed and used. This includes all of the necessary installation components. Usually, a laser beam device is customizable and should be installed by a qualified electrical/mechanical technician.
Press Brake Foot Pedal
Most press brake safety systems that abide by OSHA standards incorporate a press brake foot pedal in addition to other safeguarding devices, such as light curtains, restraints, or barriers. This acts as an emergency stopping provision in case the other press brake safety measures in place fail to protect the operator or anyone else in the vicinity. There are various types of press brake foot pedal systems, but all of them should include a press brake guard around the device to prevent accidental pressing. The guard can be metal or even plastic, but should be brightly colored so it can easily be differentiated from the color of the floor.
How Does a Press Brake Foot Pedal Work?
Foot pedals for press brake safety do not always act as the sole activation lever. They are sometimes an extra step that must be initiated to prevent accidental engagement of the machine. They greatly reduce the risk of accidents this way, but may also be used as the sole means of activation. If the foot pedal is all that is needed for operation, this can leave the press brake operator’s hands free before, during, and immediately after the stroke. The pedal must be pushed down in order for the machine to operate in either case, sole operation or in combination with another lever.
Automatic Stroke Stop Device
There are some foot pedals that use a method of two-press operation. The first press lowers the die to a distant of 6 mm from contact; a second press initiates contact. This gives the operator another chance to make sure that their hands and objects that don’t belong are not at the point of contact before the stroke takes place. This method also allows the operator to step off of the pedal completely and adjust the piece without having to make contact with the foot pedal before initiating the stroke.
Is a Press Brake Foot Pedal Required by OSHA for All Press Brakes?
A press brake foot pedal is not listed by OSHA as a general requirement for all machines. Although they may or may not necessarily be required for your press brake, a press brake foot pedal helps to protect workers and can leave the operator’s hands free, which can dramatically speed up productivity.
OSHA Standards Compliant
The Brake Master is designed to provide stop time monitoring for part revolution punch presses. It is designed to meet the safety regulations requirements of OSHA 1910.211(d) and 217. The BM 1000 Brake Master meets all published USA OSHA, ANSI, and CSA requirements.
Each time the machine comes to a stop anywhere in the cycle a stop time test is performed. The calculated stop time is compared to a failure parameter and in the event the calculation exceeds the parameter the machine is prevented from making a successive stroke until the Brake Master is reset.
To help in the proper maintenance of the machine the Brake Master provides a brake warning in the event the stopping time of the machine begins to deteriorate but does not exceed the failure parameter, allowing ample warning time to adjust or repair the clutch/brake mechanisms.
Brake Time Test
Upon installation, it is necessary to perform a stop time test of the machine to determine the brake failure parameter. This test is designed to determine the worst-case machine stop performance scenario by forcing the machine to stop at ninety degrees with the heaviest upper die installed. A sequence of ten stop times are made, then the highest stop time is multiplied by 1.25 percent to determine the failure parameter and 1.10 percent to determine the warning parameter. This test can be performed at any time and as often as desired.
The Brake Master displays the stop time in milliseconds, stop time in degrees, strokes per minute and a safe distance calculation for determining safe distance of operator controls and presence sensing safety devices.
Program batch counts and if desired perform a press top stop upon completion of the batch.
Metal Tech Controls Corp
Metal Tech Controls Corp.’s Brake Master meets all OSHA Standards. For more information, contact us any time and we will be sure to answer any questions you may have. For more information on press brake safety visit pressbrakesafety.info.
How A Press Brake Operator Is Kept Safe With Laser Sentry
The Laser Sentry provides press brake safety for the press brake operator by eliminating the hazard in a similar manner as do elevator and subway doors eliminate the hazard of the doors closing and crushing someone. In the event the doors are blocked, the doors retract automatically. Thus, eliminating the hazard! They use pressure sensitive switches to detect the presence of an object or the press brake operator. When the sensor is activated the doors retract.
Interruption of the Laser Beams
The Laser Sentry uses the interruption of lasers beam to sense objects. If any object breaks any of the three beams, press brake operator or otherwise the ram instantly retracts.
To permit the bending process the Laser Sentry determines when it is safe for the laser beam to be broken. That is, when the hazard is less than 1/4 inch.
To determine just exactly where that “safe” point is, a precision digital absolute position transducer is used. The transducer provides the rams position within .0025 inches of repeat ability.
Press Brake Operator Teaches the Laser Sentry
The press brake operator “teaches” the Laser Sentry. The press brake operator teaches the exact position of the surface part to be formed when it is resting on the lower die. This position is used by the Laser Sentry to determine the safe area of ram travel.
However the laser is not “muted” at 1/4 inch above the material as with the use of light curtains, it is muted .100 above the surface of the part being formed!
The beam is scanned between 3/16 and 1/4 of an inch under the die. This distance is determined by the reversing capabilities of the machine. The Laser Sentry tests the reversing time and this time of ram travel distance is used to determine just how far below the die the beam can be placed.
As the ram travels down or up in the case of an up-acting press and any of the beams are broken before the die reaches to within .100 of the part to be formed, the ram will retract immediately.
Slow Speed for Press Brake Operator Safety
The machine’s slow speed function is used to reduce the risk of pinching even further. As the ram approaches to within a minimum of 1/4 inch above the part, the Laser Sentry forces the machine into slow speed. In slow speed the reaction time of stopping and reversing the machine is considerably reduced. Thus, allowing a greater margin of safety as the die closes.
High Speed, Pulsed Lasers
To provide as near fail-safe operation as possible, the laser beam is pulsed at very high speed. A separate microprocessor monitors the laser pulse. It will detect any malfunction in the laser transmitter or receiver and shut down the machine.
Two safety relays that are crosschecked by both processors are provided to control the ram motion valves.
An input from the machines’ control circuit that signals the ram to move is monitored. When activated the Laser Sentry knows that ram motion is to begin and be maintained until the signal is de-activated. The Laser Sentry uses this information to monitor the output of the position transducer. Should it fail, the system will be shut down immediately.
Control reliability is provided by two microprocessors to maintain the transducer and the control the Laser Sentry’s operation. All, while cross checking each other for proper operation.
Metal Tech Controls Corp
Metal Tech Controls Corp.’s Laser Sentry meets all OSHA Standards. For more information, contact us any time and we will be sure to answer any questions you may have. For more information on press brake safety visit pressbrakesafety.info.