Manufacturer of Hydraulic Presses

Machinery Safety - C-Frame press - Light Curtains

July 4, 2019

Manufacturing companies use heavy duty types of machinery that operate at high speeds and can cause injuries to both
operators and the workers. On the other hand, companies are trying to increase workout put by using machines or equipment that are easy to use, fast and complex. When this happens, there is a high possibility that the workers/operators will get injured/hurt if they are using machines that perform activities like pressing, welding or cutting. As a result, assembly lines and manufacturing companies that have hazardous machinery try to find better and safety measures to guarantee their workers’ safety.

Safety light curtains are among the safety measures in assembly lines to keep the workers safe. These curtains can be used to limit unsafe access or unwanted access to machines either by operators/workers or by any unauthorized personnel. Normally, safety light curtains e.g. in a C-frame press are installed at two opposite ends of areas that are deemed hazard or an area that should be accessed by designated machine operators. Unlike traditional safety methods like pull back restraints, mechanical barriers, and sliding gates, safety light curtains are reliable, efficient and offer reduced fatigue to workers. For instance, since the operators do not have to do any heavy lifting, light curtains can simplify routing tasks such as machine set up, maintenance, repair, and servicing.


How do light curtains on a C-Frame press work?

Safety light curtains are made of two heads i.e. a transmitter head and a receiver head. The two heads have both optics and electronics to send and receive infrared lights. These curtains are installed at two opposite ends so that they can create a virtual curtain using the infra-red lights produced from the transmitter end. In case someone, a part of a human body or a foreign body interrupts the beams of light (the infrared light), the controller relays a stop signal. Therefore, the running machine is halted/stopped abruptly to prevent injuries or damage to the machine.

The transmitter head contains LEDs that produce invisible pulses of infrared at a frequency that’s not only specific but also modulated. It is important to understand that the receiver head/unit can only detect specific pulses and frequencies to guarantee machine safety and reliability. To further improve and guarantee the safety of workers, the controller head/ unit is made up of the following features:

  •  Status & diagnostic indicators
  •  Supporting logic
  •  Power supply
  •  User controls
  •  Output relays

Even though light curtains use infrared rays, they are different from photoelectric sensors because they have control reliability design. This is because all machine control systems that are related to safety should adhere to OSHA and ANSI requirements. Therefore, for safety light curtains to meet the Control Reliability requirement, the systems should have the ability to self-check its circuitry to determine if there are any internal faults. In case the system detects any internal faults, a stop sign is relayed to the machine being guarded before the safety light curtain initiates a lockout state. This ensures that the machine will only be able to operate again after the faulty component is replaced or replaced and appropriate safety system reset. This is an important safety requirement because safety light curtains do not use physical barriers to provide safety to the workers.


Therefore, in case of the system failure, the machine will stop running thus prompting the operators to check the system and/or the safety system to identify and fix the problem before resuming the normal operation. Finally, it is important to understand the importance of guaranteed safety to your workers to avoid injuries or severe damages if you own heavy duty machines like C-frame hydraulic presses.