Apparatus for applying a liquid material and method for determining a function used to operate the apparatus

A method for determining a material-specific function for a control unit of an apparatus for applying a liquid material to a plurality of parts, said apparatus comprising:

• at least one first gun through which the material can be applied to the parts;
• a reservoir for holding the material, the reservoir being fluidically connected to the at least one first gun;
• a pressure system for providing a gas pressure acting on the material located in the reservoir, the pressure system comprising a pressure regulator by means of which the gas pressure acting on the material can be adjusted, and a pressure sensor for detecting the gas pressure acting on the material;
• a temperature sensor for detecting temperature of the material;
• a control unit in which a material-specific function is stored which specifies a setpoint value for the gas pressure which depends on the detected temperature of the material;
• wherein the method comprises predetermining different temperatures of the material via a heat unit;
• setting the gas pressure, depending from the predetermined temperature, such that a film weight per part emitted by the at least one first gun is the same for the different temperatures in each case, wherein the material-specific function is determined on the basis of the set gas pressures and the predetermined temperatures.