Press moulding method

A method of press moulding a moulding material to form a vehicle body panel of fibre-reinforced resin matrix composite material, the vehicle body panel having a front A-surface and a rear B-surface, the method comprising the steps of:

• i. providing a heated mould tool having a lower mould part and an upper mould part, the upper mould part having a first moulding surface for moulding a front A-surface of the vehicle body panel and the lower mould part having a second moulding surface for moulding a rear B-surface of the vehicle body panel;
• ii. providing a multilaminar panel of moulding material comprising at least one layer of fibres and at least one layer of resin, the multilaminar panel having first and second opposite major surfaces, a surface resin layer of the multilaminar panel being at or adjacent to the first major surface and a dry fibre layer of the multilaminar panel forming the second major surface;
• iii. locating the moulding material in the mould tool, wherein in the locating step iii the second major surface is draped onto the second moulding surface of the lower mould part, and the lower mould part is at an elevated temperature as compared to the temperature of the moulding material;
• iv. closing the mould tool to define a substantially closed mould cavity containing the moulding material, wherein the closing step iv comprises progressively closing the mould tool to define the substantially closed mould cavity containing the moulding material, the closing step including:
• a preliminary closing phase to achieve mutual engagement between the lower and upper mould parts,
• a secondary closing phase after engagement between the lower and upper mould parts with the mould tool partially closed to define a closed intermediate cavity containing the moulding material, the closed intermediate cavity being larger than the moulded part and the first moulding surface of the upper mould part being spaced from the first major surface by a spacing distance, in the secondary phase air being at least partially evacuated from the closed intermediate cavity while the first moulding surface of the upper mould part is spaced from the first major surface to provide a vacuum pressure, and
• a tertiary closing phase after the vacuum pressure has been provided in the closed intermediate cavity, the tertiary phase having:
• I. a first stage prior to both the first moulding surface contacting the first major surface and the second moulding surface contacting the second major surface, and
• a second compression stage after both the first moulding surface has contacted the first major surface and the second moulding surface has contacted the second major surface, the closure speed of relative movement between the lower and upper mould parts being higher in the first stage than in the second compression stage;
• v. applying pressure to the moulding material in the mould cavity to configure the moulding material in a fully moulded shape, wherein after the applying pressure step v, resin in the multilaminar panel fully impregnates the dry fibres;
• and
• vi. substantially fully curing the resin to form a vehicle body panel from the moulding material, the vehicle body panel having a front A-surface formed from the first major surface and a rear B-surface formed from the second major surface.