Contact Angle, Surface Interface Tools

Special Instruments


During the production of rolled steel, tin, or aluminum sheets, oils such as DOS, CSO or ATBC are being used as a coating medium to prevent sheets from rusting. Monitoring the amount of oil coated on the sheets is essential to ensure the production of high-quality metal sheets.
Using test metal sheets from the production line, our Automatic Spread Oil Measuring Apparatus SOM-A determines the oil amount by transferring the oil coated on the rolled metal test sheets onto a water surface and detecting the change of the surface film pressure. This method is called the “hydrophil balance method”.

  • Utilization of the Wilhelmy plate method to precisely detect the surface film pressure and to determine the oil volume in the range of μg on a test metal sheet
  • Two independent temperature control systems to ensure reliable results and high repeatability even in difficult measuring environments
  • Indication of the oil volume in mg/m2 on a LED display
  • Easy to clean Teflon-coated trough with excellent corrosion resistance
  • Easy to clean measuring probe (glass plate)
  • Periodical calibration of the balancing system can easily be done by the user
  • Step down voltage transformer to convert foreign voltages to AC100V of the SOM-A
  • Monitoring the amount of the oil coated on rolled steel, tin or aluminum sheets
Dimensions (WxDxH) 1300x650x860mm (excluding water circulator and water supply system)
Electric power:
Power consumption

50/60 Hz
Operating environment

temperature: +10 to +35℃, humidity: 30-80%RH (non-condensing)
positioned away from sources of electrical noise and vibration

Individual Components

  Oil Volume Meter
Measuring range 0.3 to 17.5mg/m2
Digit & Resolution 0.1mg/m2
Display method LED digital display
Accuracy ±2.0%FS (based on +35℃)
Dimensions (WxDxH) 450x250x160mm (body only, excluding protrusion)
Weight 6.0kg


  Automatic Surface Film Pressure Meter
Measuring method Wilhelmy plate method
Measuring range 0 to 50.0mN/m (analog meter)
Accuracy ±0.5%FS
Dimensions (WxDxH) 450x250x160mm (body only, excluding protrusion)
Weight 6.0kg


  Oil Film Spreading Trough
Internal Dimensions

Cylinder section size

Dimensions (WxDxH) 775x180x115mm


  Film Pressure Compressing Unit & Drive Motor
Compressing speed 500mm/min (fixed)
Dimensions (WxDxH) 1120x280x220mm


  Environmental Chamber
Dimensions (WxDxH) 1300x650x700mm


  Automatic Sample Dipping Unit
Dipping repetitions 1 to 9999
Dipping speed range 6.0 to 1.7sec (for one complete cycle)
Dimensions (WxDxH) 330x150x240mm
Weight 11kg


  Refrigerating & Heating Water Circulator
Temperature range +5℃ above RT to +95℃
Control accuracy ±0.05℃
Control method PID
Safety functions

Diagnosis functions
(max/min temperature abnormality, heater breakage, sensor abnormality)
Heater capacity 1.0kW
Bath volume 5.5L
Circulation pump Max. 5L/min
Tubing diameter of

Power consumption 1.1kVa
Dimensions (WxDxH) 194x306x359mm (body only, excluding protrusion)
Weight 8kg


  Heated Water Supply System
Temperature range +30 to +75℃
Control method Thermistor
Safety functions Temperature fuse, manual reset
Heater capacity 1.1kW
Bath volume 25L
Pressure reducing valve 0.08MPa
Dimensions (WxDxH) 360x395x390mm (body only, excluding protrusion)
Weight 13kg (38kg being water-filled)