Pushed mostly by European standards and advances, machine perimeter protection in the U.S. has come a long way in a short time. Door interlocks, perimeter ropes, and through-beam sensors are some of the devices used to monitor potentially dangerous, or pinch-point, machine-operating areas.
"The usual approach to robot cell protection is to fence around the cell, except for an entry for operators to load or unload parts, but still protect when the cell is operating," says Russ Woods, application engineering manager at Omron STI, which works extensively with robotic welding cells. The safety technology company recently added the F3SJ family of light curtains, which includes an embedded muting controller, and the OS3101 laser scanner, which initiates a warning prior to safety-zone encroachment, to its line of solutions.
Sick AG has a 60-year history of providing safety systems, including a claim that it offered the first machine-safety light curtain in 1951. Recently, Sick launched a complete range of perimeter safeguarding devices to target a wide variety of applications ranging from simple machine perimeter guarding to advanced entry/exit applications for palletizing.
Sick's M4000 standard model can be tailored to meet specific applications. It includes an integrated laser alignment system that decreases installation and commissioning costs, while increasing machine availability when quick installation or realignment is necessary. This is especially true for perimeter guard applications that require long distances or the use of several reflective mirrors.
M4000 has an optional integrated LED lamp that provides 360° visibility of the safety system's status. Other options include a separate reset connection at the receiver and an option to support AS-i Safety at Work. No configuration software is required.
Columns now are available that incorporate individual mirrors for each barrier beam, making mirror adjustment extremely simple.
Melitron Corp. has installed a number of M4000 Standard perimeter safety products at its Guelph, Ontario, facility. "We have seven installations of M4000 safety curtains (with two mirrors) on NCT turret cells with auto-load/unload," says Sean Spencer, operations manager at Melitron.
The M4000 advanced model offers safeguarding solutions for typical point-of-entry applications such as access protection to conveyer systems, palletizing equipment, and robotic work cells. Together with a muting module, it forms an efficient solution for decentralized conventional muting applications involving automatic material transport.
The M4000 area model is based on the same technology platform as the M4000 standard. However, it's optimized to prevent manual machine startup when someone is standing in a working area.
"Our perimeter safety product developments are based solely on customer feedback," says Israel Alguindigue, Sick Automotive Group's market manager. "We actually tailor the guarding to particular shapes." This is good news for material handling and palletizing machines, in which certain carton shapes are allowed to pass through the protection beam, but larger objects such as humans are not.
Meanshile, Pilz Automation Safety LP recently launched its new SafetyEye 3-D, safe camera system for monitoring machine perimeter.
Developed in conjunction with Daimler-Chrysler, SafetyEye places an invisible, customized, 3-D protective cocoon around a work area. This system offers increased safety without barriers, detection zones that are configurable easily on a PC, and fast diagnostics for rapid troubleshooting.
"Camera-based image processing will revolutionize safeguarding, and not just in the industrial sector," says Renate Pilz, Pilz's managing partner.