The L29 single-beam photoelectric safety switch stops dangerous movements if someone reaches into the forming station in a thermoforming packaging machine.
Conventional single-beam photoelectric safety switches from SICK were too big so the firm developed one from photoelectric switches used for detection in automation technology.
SICK has also developed inductive proximity sensors, fork sensors, photoelectric retro-reflective sensors for transparent objects and encoders for packaging machines used in the food industry with Multivac.
Single-beam photoelectric safety switches have self-testing senders and receivers or testable senders and receivers combined with an evaluation unit.
Thermoforming process
The processes of a packaging line can be controlled centrally via the HMI 2.0 user interface from Mutivac, making it possible to monitor data and process it electronically.
The forming station in the thermoforming packaging machine creates packing moulds. The machine uses heat to warp the foil and compressed air and a vacuum to thermoform it.
It is then transported to the infeed area where the moulds are filled with products.
As this is done mechanically the transition from the forming station to the infeed area must be secured so the machine movement stops as soon as a person enters the area.
The safety switch slots into the HMI 2.0 user interface from Multivac and has enclosure ratings IP 67 and IP 69K as well as Ecolab approval.
The sender axes can be retained as the photoelectric switch can be fitted in the same position as previous switches.
Sensor housing and design
VISTAL housing had to be adapted to the Multivac design and logo and part number from the firm had to be visible on the sensors.
SICK said it is resistant to chemicals so there are no issues using cleaning agents which are essential in hygienic environments such as the food sector.
As Multivac did not want the switch to interfere with the safety concept of the machine, it was also adapted to match the design of the packaging machines.
For safety reasons, the maximum permitted aperture angle must be observed as if it is too large, the sensor cannot detect hands or fingers due to the reflective surface.
The L29’s PinPoint LED with its visible light spot uses SIRIC optical technology making the switch more powerful than conventional alternatives.
SICK said it is not sensitive to known optical and high-frequency influences such as ambient light, vibrations, or electromagnetic influences.
Multivac’s portfolio covers tray sealers, vacuum chamber machines, chamber conveyor belt machines, labelers, quality control systems, and automation solutions to turnkey lines.
Meanwhile, Multivac is planning to invest 15m levs (€7.6m) in a plant for machine parts in Bulgaria over the next three years, local media reported, quoting the country's economy ministry.
The plant will be in Sofia's industrial zone and create around 70 jobs. The firm already operates in Bulgaria with a site employing 35 people.
- SICK sensor story based on article which first appeared in SICK insight