Safe and rugged: Experts at MAN, HELLER and SICK perfect the deTec safety light curtain

Polycarbonate is a proven material in the machine tools segment. SICK’s deTec4 Core safety light curtains are correspondingly equipped with polycarbonate front screens as standard. When, in 2016, MAN Truck & Bus commissioned a complete machine park with 14 HELLER CNC machining centers for milling and drilling work, there was no reason not to use the proven material. In response to a request from MAN, HELLER had equipped the machining centers, which they had specially designed for MAN, with deTec4 Core safety light curtains from SICK to safeguard the machine doors. Everything went well at first. After a few months, however, the light curtains suffered more and more failures because their polycarbonate front screens were broken near the end caps at the bottom, resulting in machine downtime.

During the fault analysis, coolants and lubricants were at the top of the list of suspected causes because their chemical compositions often change and there are no labeling requirements. The suspicions were confirmed when experts at SICK’s Repair Center examined the returned devices and carried out tests in the plastics laboratory with samples of the coolants, lubricants, and detergents used by MAN. The specialists from MAN, HELLER, and SICK all agreed that the only reliable solution to this problem had to be in a form that was independent of whatever composition was used. This meant thinking beyond the hitherto successful use of the plastic polycarbonate.

Rugged and resistant – even in extreme conditions

 

Glass is one of mankind’s oldest materials. Thermal toughening results in an internal change in its structural stresses, increasing its bending strength. Smaller notches and scratches cannot do much damage to the glass; cracks or ruptures are prevented. What is ideal for touchscreens may also be advantageous with aggressive fluids or gases, the team of experts thought. SICK decided to develop a product variant of the deTec with a front screen made of chemically hardened, pre-stressed float glass and use it for the first time at MAN. “Thanks to the glass front screens, the new deTec HG safety light curtains are resistant to aggressive coolants, lubricants, and detergents. We no longer have any unplanned downtime,” MAN confirmed. “We are very satisfied with this result and the excellent collaboration with the experts from SICK.” The CNC machining centers for milling and drilling work during axle production at MAN Truck & Bus in Munich have been equipped with deTec HG safety light curtains since early 2018. The deTec HG protects operators and is a safe investment for the operating entities – because regardless of the composition of the coolants, lubricants, and detergents used, the safety light curtain ensures a plant stop as soon as an employee reaches into the machine when the door is open. And only then. Unwanted downtime is a thing of the past, and machine availability remains high.