Molds of press brake machine

  Description 

  Laser beam devices or camera systems are electro sensitive devices that use a LASER-type light source in the infrared spectrum. They detect any intrusion between the upper die and the lower die, until the laser beam is 6 mm from the sheet. At less than 6 mm, the laser beam device is deactivated. 

  The laser beam device is attached to the upper table and is height adjustable. For positioning in relation to the die on the ram, the following must be taken into account: 

- the distance between the highest laser beam and the point of the upper die, which must not allow a finger to enter without it being detected, - the ram’s stopping distance. 

Furthermore, the associated control device for closing the dies must be a three-position pedal control [OFF/ON/Emergency stop]. This pedal must be maintained in an intermediate position to allow the dies to close.

  Modes of operation 

  Detection under the upper die is done in three zones: front (zone 1), central (zone 2) and rear (zone 3). The modes of operation available are: 1. Regular mode in which the three detection zones are active. This figure case is possible, for example, during a first bend. The operator has maximum protection in this mode. 

  2.Box mode, in which the front zone is deactivated to avoid stopping due to a perpendicular bend. 

  3.3. Box and back gauges mode in which only the central zone is active. The front and rear zones are deactivated to avoid stopping due to a perpendicular bend and the presence of the back gauges as with a bend near the edge. 

  The last two modes should be used only when necessary because the press is being operated with reduced safety.

  Products available 

  Each manufacturer has developed his own method for protecting the operator: protection volume, vertical lines, horizontal lines, etc. In 2008, five manufacturers were identified, and their proposed products generally use the three modes of operation explained above, and can be used in category 4 safety circuits according to ISO 13849-1: 2006.

  Advantages of a laser beam device

  1.Protects all persons accessing the space between the dies. 

  2.Limits the frequency of undesirable stops since the detection zone is restricted to the region located directly under the upper die. 

  3.Allows the sheet to be supported by the hands. 

  4.Adapts to the manufacture of boxes and small parts as well as to the presence of back gauges in the bending zone. 

  5.Complies with ROHS (section 179) and CSA Z142-02 if correctly installed.

  Temporary during installation 

  1.Requires revision of the bending sequence, mainly for bending complex parts. Where a solution is foreseeable 

  2.Height adjustment costly in time for each change: - of die - of sheet thickness. Solution: Some models do this adjustment automatically. 

  3.Increases unwanted stops when the sheets are not flat. Solution: A magnet on the working surface of the lower table can reduce the problem. Permanent 

  4.May not function with certain shapes of complex dies (e.g., die with several heights). 5. May not function for sheets exceeding the width of the press

  TWO-HAND CONTROL DEVICE 

  (Protective device for the sole person using it) 

  REMINDER The protection offered by a two-hand control device is based on the safety distance, which is mainly a function of the ram’s stopping time. It is therefore essential that this stopping time be reliable and repeatable before considering using this means of safeguarding (see Appendix 8.A). 

  Description 

  The two-hand control device is a two-button control device, whose simultaneous and maintained action initiates the start of the ram of the hydraulic press brake and ensures its movement. 

  To fulfill the role of protective device for the operator who uses it, it is important that the two-hand control device be installed at a safety distance (see Appendix 8.A) that prevents all contact of the operator with the hazards identified for the zone in front of the press. 

  Since the operator has both hands occupied by the twohand control device, a sheet support may be installed to support the part.

  Advantages of the two-hand control device

  1.Relatively simple solution. 

  2.Complies with ROHS (sections 180 and 181) and CSA Z142-02 if correctly installed.

  Constraints of the two-hand control device

  Where a solution is foreseeable 

  1.Its use does not allow bending of all types of parts, because the material to be bent may have to be supported by both hands before or during bending. 

  Solution: 

• Install a sheet support (see page 25), and 

• Use the two-hand control device and pedal solution to support the sheet during bending. 

  2.May be the reason for musculoskeletal disorders caused by repeated pushing movements on the buttons. Solution: A touch-sensitive two-hand control device in order to reduce the effort. 

  3. Removable two-hand control device must be designed to comply with the safety distance. Permanent 

  4. Protects only the person operating it. Plan for ways to safeguard the other people around the press. 

  5. If there is more than one operator, a two-hand control device is necessary for each one, with a selector switch on the control panel. The selector switch indicates the number of operators involved in bending and forces each of them to activate it for each cycle.