Latest News

• return to the news page

Key issues facing press brake manufacturers

Lazer Safe has for many years not only been an industry leading technology developer and supplier, but has also been active in working closely with press brake manufacturers in providing expertise and understanding in European and world safety standards and how these standards can be best applied utilising Lazer Safe technology to achieve the highest possible levels of machine safety, reliability, functionality and performance.

 

Through continued work in this area, Lazer Safe has published a series of papers titled 'Building performance press brakes with Lazer Safe systems to meet world machinery and safety requirements'. The document addresses key issues facing press brake manufacturers including:

1. Design and manufacture of a Quality, Productive, Cost Effective machine
2. Compliance with World Machining and Safety Standards. Particularly EN12622 for CE markets
3. Meeting end-user needs: Functionality; Performance – parts per hour, accuracy of bend, repeatability, ease of use; Reliability.

The document provides a set of summary papers setting out Lazer Safe views on topics relating to these issues and provides excerpts from EN12622 appropriate to them. 

 

Papers

1. A Well Built Press Brake
2. Press Brake Speed Zones
3. Adjusting the Change of Speed (Ramp)
4. Overrun Monitoring (Stop distance monitoring)
5. Safety Speed (slow speed) requirements
6. Box bending mode operation
7. Lazer Safe compliance with EN12622

 The following is an excerpt from the fourth paper in this series:

OVERRUN MONITORING (Stop distance monitoring)

Requirement EN 12622

The standard provides the following Definitions:3.1.21 overrun movement (distance) of the beam past a defined stopping point.3.1.22 overrun monitoring device that provides a signal to inhibit further complete stroke when the overrun exceeds the pre-set limit(s).  When a laser actuated AOPD is used section 5.1.1.5 – part l statesl) An automatic press brake overrun monitoring function shall be provided. 

 

Implication

As the clause 5.1.1.5 states, overrun monitoring is to be automatic, that is, to be activated automatically whenever the overrun is detected. 

 

Reasoning

The reason for this extra automatic requirement above a light curtain installation on a press brake is because these laser activated AOPD's (Lazersafe, AKAS, V4000, DFS etc) are situated at the very last point of safety – the dangerous tool at the pinch point - not a distance away as per a simple safety barrier (light curtain). If a failure occurs there is no second chance, or the benefit of extra distance away from the dangerous point.It also means that the laser activated AOPD must always be active and fault free and always fully responsive to commands given to it.The overrun distance must of course correlate to the safety distance (distance between top tool tip and active laser beam) required by the specific guard system fitted to the press brake. This is closely tied to the stopping distance that the guarding system can achieve with the press brake. The tool must not travel far enough after a stop is requested by a laser beam interruption to touch the obstruction.A truly 'Automatic' overrun device will ensure this, not just because it will stop the tool if an overrun is detected when a finger or limb is in harms way (hopefully an extremely rare occasion), but also because it knows that the system is capable of achieving this stop capability, whenever it is called upon. The standard describes this part of the guarding system as category 2.  These categories dictate the level of internal safety checking of devices.  In this case cat 2 is used to require this device to be checked (ensure that this device is functioning) at each power on or every 24 hours.  This gives adequate evidence that the device will perform to its 'Automatic' requirement if and when called on.The reason Cat 2 was selected by the CEN/TC 143 WG1 group for this Automatic overrun was that if Cat 3 or 4 was stipulated then the testing of the function would need to be done on every cycle.  This would mean that a stop would need to be introduced into every cycle (e.g. such as stop at mute point), so that the test could be performed.  This of course would be detrimental to production and the operator would try and find every way possible around this and therefore jeopardize the whole safety and guarding system just for this point.It was accepted by the group that if the system was 'automatic' then the actual practical function of checking if there is an overrun would be performed every time the machine stopped – e.g. when take foot off the pedal, interruption of the beam, box bending, instructions from the machine controller, etc.  Therefore, the checking for overrun in practice will be done many times during a 24-hour period.  Then the actual integrity of the device/function is done every power up or 24 hours to check the function/device is functioning correctly, and will perform when required. 

 

Implementation

It is therefore an expectation of the standard that 'overrun monitoring' will automatically be carried out every time the machine stops, therefore ensuring that the integrity of the whole press brake/guarding system integration is correct, fully responsive, and within tolerances, at regular intervals during the operation of the machine.

 

Risk Area:

Some manufacturers without this full understanding may after a quick reference to the tables in EN12622 (used to set Categories to devices and functions), assume that overrun monitoring – in itself – is indicated as only needing to be done once on start up, thus providing a on start-up solution only.  This does not address the full requirement for an 'AUTOMATIC' OVERRUN FUNCTION, as is defined in the body of the standard and described in detail above. 

 

To request a complete copy of this document please email customerservice@lazersafe.com.au

---

More News

• 1-4-10
  

  Fabtech 2010

  North America's largest metal forming, fabricating, finishing and welding event heads to the Georgia World Congress Center, Atlanta, Georgia, November 2-4, 2010. This annual event anticipates 22,000 visitors and over 1,000 exhibiting companies covering more than 350,000 net square feet of floor space. [full article]
  
  
• 16-7-09
  

  NEW - IMG-100 Learning Mode video

  NEW - Angle Confirmation Learning Mode video [full article]
  
  

Latest events

• 20-11-09
  

  EuroBLECH 2010

  EuroBLECH, the World's No.1 sheet metal working exhibition, showcases cutting-edge technology and intelligent solutions. The trade show is themarket place for business at an international level and is the key platform for innovation and ideas. [full article]