Method for producing a counter-form and method for manufacturing a part having a complex shape using such a counter-form

A method for producing a counterform (20, 30a, 30b) for manufacturing a part of complex shape (1;

• 24d) by pressure sintering densification, the counterform (20;
• 30a, 30b) is formed of successive layers produced by digitally controlled three-dimensional (3D) additive printing, the method comprising the following steps:
• digitally recording a three-dimensional negative (3) of the part to be produced (1;
• 24d) in a control unit of a three-dimensional additive printing system in order to make a print of the counterform (20;
• 30, 30b) to be produced, the rest of the counterform having faces of suitable shape for a mold for manufacturing the part (1;
• 24d);
• producing the counterform (30a, 30b) by means of a 3D additive printing technique, the size of the counterform (20;
• 30a, 30b) being increased by a density stretch factor that compensates for a shrinkage in the size of the part to be manufactured (1;
• 24d) in the direction of the uniaxial pressure (F) applied during the sintering densification of the part to be manufactured;
• completing the additive printing of the counterform (20;
• 30a, 30b) by sintering;
• and
• wherein the counterform (20;
• 30a, 30b) is produced from a porous material chosen so that the materials of the counterform (20;
• 30a, 30b) and of the part to be manufactured (1;
• 24d) exhibit the same behavior on sintering.