Manufacturing of wind turbine blade spar cap

A method of manufacturing a fibre-reinforced spar cap for a wind turbine blade, the method comprising:

• providing a spar cap mould;
• arranging a plurality of pultruded fibre plates in the spar cap mould to form a stacked arrangement of pultruded fibre plates, wherein the stacked arrangement comprises a first lateral surface and an opposing second lateral surface;
• arranging a first insert member next to the first lateral surface of the stacked arrangement, wherein the first insert member comprises a connecting surface, and wherein the first insert member is arranged such that the connecting surface of the first insert member abuts against the first lateral surface of the stacked arrangement;
• optionally arranging a second insert member next to the second lateral surface of the stacked arrangement, wherein the second insert member comprises a connecting surface, and wherein the second insert member is arranged such that the connecting surface of the second insert member abuts against the second lateral surface of the stacked arrangement;
• placing a vacuum foil over the stacked arrangement and the first insert member and the optional second insert member;
• infusing resin into the stacked arrangement and the first insert member and the optional second insert member;
• curing the resin to join the stacked arrangement and the first insert member and the optional second insert member to form the fibre-reinforced spar cap or a preform thereof;
• removing the vacuum foil;
• demoulding the fibre-reinforced spar cap or the preform thereof from the spar cap mould;
• and
• trimming or grinding at least part of the first insert member and/or at least part of the optional second insert member of the preform to form the fibre-reinforced spar cap after curing the resin.