Method for expanding an end of a pipe and expander tool

An expander tool for expanding an end of a pipe made of plastics having shape memory, the expander tool comprising a tool head which comprises expanding means arranged to be insertable inside the end of the pipe for expanding the end of the pipe, the expander tool comprising:

• a temperature sensor, and
• an electronic control unit for adjusting at least one of the expansion control parameters of the tool head on the basis of the measured temperature value, wherein the temperature sensor is arranged to measure the temperature of the pipe to be expanded directly by making contact to the pipe;
• wherein the tool head comprises a plurality of spreading elements forming the expanding means, the spreading elements being radially movable in relation to a center longitudinal axis (x) of the tool head between a starting position (I), at which the spreading elements are close along the axis (x) and are insertable into the end of the pipe, to an outwardly extended expansion position (II) radially distanced from the axis (x) so as to expand the end of the pipe, each of the spreading elements having an outer spreading surface configured to press against an interior surface of the end of the pipe;
• and
• wherein the temperature sensor is arranged to the spreading element to measure the temperature by making contact to the pipe.