Method for manufacturing a preform building element and oven

A method for manufacturing a preform building element used for building a rotor blade of a wind turbine comprising:

• arranging a plurality of components at least partly overlappingly in a component stack on a surface of a carrier, wherein the component stack comprises a plurality of sections with overlapping components between which a binding agent is arranged, wherein the sections of the stack comprise at least partly a different thickness and/or different types of components;
• and
• heating the component stack using a heating source for activating the binding agent, wherein during the heating, at least one heat input reduction is used to reduce the heat input in the binding agent in at least one of the sections of the component stack for reducing binding agent migration during the activation;
• wherein a heating source providing a hot airflow streaming above the components is used as the heating source and at least one air flow separator is used as the heat input reduction,
• wherein the air flow separator separates at least a part of the volume above the component stack for locally reducing the air flow speed above at least one of the sections of the component stack, and
• wherein an air curtain arrangement providing at least one air stream towards at least one of the sections of the component stack, to an edge of the section, is used as the air flow separator.