Process for determining the changeover point when producing plastic injection mouldings and die-castings

A process for determining a changeover point in the production of an injection moulding or die-casting, whereby employing an injection device, a cavity of a mould is filled according to a filling program up to the changeover point after which a pressure in the cavity curve is generated according to a hold pressure program, performing several successive measurements of the pressure inside the cavity and determining after each measurement whether the changeover point has been reached or not by algorithmic processing of the current measured pressure value and previous measured pressure values in a computing unit, characterized by:

• the algorithmic processing of the measured pressure values by functional combination of classification pressure variables derived from the measured pressure values using fuzzy logic;
• a first classification pressure variable being derived from each measured pressure value by a first classification function;
• and
• the first classification function having a constant value at low pressure values and rising at an interval beginning with a positive lower pressure limit.

A process for determining a changeover point in the production of an injection moulding or die-casting, whereby employing an injection device, a cavity of a mould is filled according to a filling program up to the changeover point after which a pressure in the cavity curve is generated according to a hold pressure program, performing several successive measurements of the pressure inside the cavity and determining after each measurement whether the changeover point has been reached or not by algorithmic processing of the current measured pressure value and previous measured pressure values in a computing unit, characterized by:

• the algorithmic processing of the measured pressure values by functional combination of classification pressure variables derived from the measured pressure values using fuzzy logic;
• deriving at least two weighing variables from the classification pressure variables in a logic stage using fuzzy logic;
• and
• determining the change over point using said weighing variables.