Cover Story: Press Brake Guarding and Safety TechnologyMarch 15, 2016 No Comments
By: Dayton Rogers
Dayton Rogers of Minnesota is the first in the country to upgrade their press brake guarding with advanced Sentinel Plus technology.
Dayton Rogers of Minnesota, LLC, a contract manufacturer since 1929, saw the unique opportunity to advance the guarding of our Amada HDS Press Brake machine. As Dayton Rogers advances, our offering to customers includes a multitude of complex sheetmetal assemblies along with stampings. The unique, tightly tolerance, and complex shapes required additional options for safety and speed. We turned to Lazer Safe Pty. Ltd. for assistance.
For the past two decades, Lazer Safe has been at the forefront of press brake guarding and safety technology. Through years of industry collaboration with press brake manufacturers and operators, the company understands the importance of maintaining machine productivity without compromising the safety of the machine operator.
The company’s latest offering is the Sentinel Plus press brake guarding system, recently launched at Fabtech Expo in Chicago. Sentinel Plus represents the very latest in retrofit guarding and safety technology, and Dayton Rogers was the first company in the United States to adopt the new technology on their Amada HDS press brake.
The Amada HDS is a high speed machine with a maximum closing speed of 473 inches per minute. Generally, when conventional guarding solutions are applied, these press brakes need to be slowed down by as much as 50 percent, so that the machine can stop within a safe overrun distance. However, through the advanced camera technology and rapid response time of Sentinel Plus, the HDS can operate safely at its maximum closing speed and without any performance restrictions, enabling a speed change point as low as 2mm about the pinch point. All of this is possible with the machine still being able to stop within a safe and monitored overrun distance limit.
While laser based guarding systems are not new to the industry, Sentinel Plus takes a huge leap forward in terms of advancing machine safety and operator protection to levels far beyond current safety standards requirements. The system also was developed and optimized for application to high speed performance press brakes, such as the Amada HDS, to enable these types of machines to be operated at their maximum performance capabilities without the enhanced safety functions impacting productivity.
Sentinel Plus delivers a number of advanced safety technologies that enhance machine and operator protection; they include automatic tool scan, BendShield and AutoSense technology, Special Tools Mode, automatic mute point management, and high speed tool collision protection.
The Sentinel Plus system comprises a laser transmitter and high speed camera receiver that are fixed to the upper ram of the press brake with an adjustable linear alloy mounting bracket system. A continuous block-shaped laser field is projected along the upper tool and the camera receiver processes images within the field. The camera receiver contains the latest in safety image processing technology that enables tool profile detection, automatic tool alignment, and high speed obstruction detection. The small 2mm resolution of the protective field and rapid response time enable the operator to hold the work piece close to the tooling and operate the machine at maximum high speed.
After a tool change and setup, the machine operator simply presses the “tool align” button on the camera receiver. The camera scans the upper tool to determine the tool tip location, and then automatically adjusts the protective zone. If the tool tip is outside of viewing range, the system provides visual indicators via a graphics user interface for the operator to adjust the receiver position up or down.
Once the tool tip is identified, the system employs BendShield technology which dynamically configures the protective zone so that it envelops the punch tip. This means that there are no gaps around or below the tool tip, so it is completely protected. The protective zone has a small object detection resolution of only 2 mm and senses obstructions entering the hazardous area from any direction. This automated alignment process takes the set-up responsibility out of the operator’s hands and ensures the protective zone is always positioned correctly according to the tool tip location.
When using non-v tooling, such as radius or hemming tools, the system can be set to Special Tools Mode. In this mode, the system scans the upper tool to determine the size and profile. If the tool is outside the normal target area, then the size and shape of the protective zone automatically is reconfigured to suit the tool profile. In cases where the tools are very wide (e.g. large hemming or flattening tools), the system automatically will adjust the mute point based on the material position and the machine will operate with an earlier and monitored slow speed transition for an added level of operator protection.
Many of the bending operations at Dayton Rogers utilize various setups that include multi-stage tooling with various tool heights and different tool profiles in the same setup. Normally, this would prove to be challenging with conventional guarding solutions—however, Sentinel Plus scans the upper tools and automatically configures the protective zone according to the overall tool profile. The automatically configured muting point also takes into account any staggered die heights to ensure safe operation and eliminates the possibility of a high speed tool collision if the operator were to make a mistake during tool setup.
Sentinel Plus is not only fully compliant with the latest ANSI B11.3-2012 press brake safety standard, but it also exceeds many of the minimum requirements outlined by the standard. Two critical requirements of the standard include automatic monitoring of machine safe speed and overrun. With laser based guarding systems, certain operations could interfere with the protective zone. This could include bending awkward shaped material, use of chains for multi-v die rotation, etc.
In these situations, the protective zone can be muted when the tool opening is greater than ¼ inch, provided the machine closing movement is restricted to a safe speed, which is 10 mm per second (23.6 inches per minute). The standard requires that the speed of the machine must be monitored automatically to ensure the safe speed limit is not exceeded. Automatic overrun monitoring ensures that the machine is, at all times, capable of stopping within a pre-defined safety distance limit whenever a stop command is issued.
The standard states a minimum requirement for machine overrun to be monitored on startup and periodically every four hours; however, it also recommends that machine overrun can be monitored automatically on startup and every time the machine is stopped (eg. sensor obstruction, foot pedal released, etc). Sentinel Plus utilizes AutoSense technology that not only provides constant automatic monitoring of safe speed and overrun (on every machine stop), but also exceeds the requirements of B11.3-2012 by monitoring machine control commands automatically, operation, and performance in real time. This adds an extra level of safety by detecting potential failures in the machine controls and hydraulic systems that could lead to an unsafe operating condition.
Lazer Safe is a technology company specializing in the development and manufacture of control, safety, and operator protection systems for press brakes. As an industry leader, the company is committed to the development and understanding of international safety standards and has representation on several international standards committees including the European CEN/TC committee, the United States ANSI B11.3 sub-committee, the ISO Standards Committee, and also is involved in a consultative capacity for other international standards committees.
Molly Barrett is the editor and publications manager for the Minnesota Precision Manufacturing Association. She can be reached at firstname.lastname@example.org.
Copyright © 2016 Minnesota Precision Manufacturing Association. For permission to use or reprint this article please contact Molly Barrett, publications manager for Precision Manufacturing Journal.