Some Photomicrosensors have cracks around the screw mounting holes. Please advise possible causes and countermeasures.

ID: FAQE40030E



Cracks and chipping near the mounting holes of the housing screws of Photomicrosensors are presumed to be caused by deterioration in the properties of the housing material due to oil and/or chemicals, in addition to mechanical stress.


In the case of built-in type Photomicrosensors, cracks in the vicinity of screw mounting holes are generally considered to be caused by the followings.

  1. Screwed with a torque exceeding the specified value.
  2. The mounting loosened and rattled due to vibration and/or impact, and mechanical stress concentrated around the screw mounting hole of the housing.
  3. Cutting oil adhering to screws and mounting brackets.
  4. Organic solvents and other chemicals are used for cleaning.

Polycarbonate is used as the housing material for most of Omron's Photomicrosensors. Please note that the following chemicals may cause degradation of properties of polycarbonate.

  • Gasoline
  • thinners
  • toluene
  • cyclohexane
  • tetrachloroethane
  • cyclohexanone
  • trichloroethylene
  • acetone
  • xylene
  • benzene
  • turpentine oil
  • chloroform
  • formalin
  • ammonia
  • caustic oils
  • cutting oils
  • etc.

In particular, cutting oil attached to screws and mounting brackets may be easily overlooked.
For other notes related to Photomicrosensors, see Photomicrosensors Precautions

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Product category Sensors Photomicro Sensors
Classification Trouble shootings
Related keywords
  • Optical Sensor
  • Trouble Shooting
  • Crack
  • Screwing Torque
  • Polycarbonate
  • Chemical Resistivity
  • Cutting Oil
  • Vibration
  • Impact

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