Moulding method

A method of moulding a moulding material to form a moulded part of fibre-reinforced resin matrix composite material, the method comprising the steps of:

• i. providing a plurality of layers of sheet moulding compound, each layer comprising a plurality of ribbons randomly distributed across the plane of the respective layer and at least partly coated by a resin, each ribbon comprising a bundle of mutually aligned carbon fibres and being randomly oriented within the plane of the layer, in each layer of sheet moulding compound the ribbons are distributed to cover less than 100% of the plane of the layer, wherein each layer of sheet moulding compound is formed by the following steps:
• (a) providing an elongate tow of carbon fibres;
• (b) spreading the tow of carbon fibres to form an elongate ribbon;
• and (c) cutting the elongate ribbon transverse to the length of the elongate ribbon to form a plurality of individual ribbons;
• (d) scattering the plurality of ribbons onto a surface to form a layer of the plurality of ribbons which are randomly distributed across the plane of the layer;
• and (e) coating a resin onto the plurality of ribbons to form the layer of sheet moulding compound, wherein in step (d) the plurality of ribbons are scattered onto a surface and a levelling force is applied to the plurality of ribbons to level out the distribution of the plurality of ribbons across the plane of the layer of the plurality of ribbons, wherein in step (d) the levelling force is applied to the plurality of ribbons by vibrating the layer of the plurality of ribbons to level out the distribution of the plurality of ribbons across the plane of the layer of the plurality of ribbons;
• ii. assembling the plurality of layers as a stack;
• iii. locating the stack in a moulding area of a mould tool, the mould tool defining a peripheral edge of the moulding area, wherein the stack of layers is shaped and dimensioned to cover from 90 to 100% of the moulding area and a peripheral edge of the stack is located at or inwardly of the peripheral edge of the moulding area, the stack of layers defining a panel part;
• iv. applying a moulding pressure to an upper surface of the stack and causing the sheet moulding compound to flow and fill a mould cavity, defined by the moulding area, of the mould tool;
• and
• v. solidifying the resin to form a moulded part from the moulding material, wherein the moulded part includes a panel portion formed from the panel part.

A method of moulding a moulding material to form a moulded part of fibre-reinforced resin matrix composite material, the method comprising the steps of:

• i. providing a plurality of layers of sheet moulding compound, each layer comprising a plurality of ribbons randomly distributed across the plane of the respective layer and at least partly coated by a resin, each ribbon comprising a bundle of mutually aligned carbon fibres and being randomly oriented within the plane of the layer, in each layer of sheet moulding compound the ribbons are distributed to cover less than 100% of the plane of the layer, wherein each layer of sheet moulding compound is formed by the following steps:
• (a) providing an elongate tow of carbon fibres;
• (b) spreading the tow of carbon fibres to form an elongate ribbon;
• and (c) cutting the elongate ribbon transverse to the length of the elongate ribbon to form a plurality of individual ribbons;
• (d) scattering the plurality of ribbons onto a surface to form a layer of the plurality of ribbons which are randomly distributed across the plane of the layer;
• and (e) coating a resin onto the plurality of ribbons to form the layer of sheet moulding compound, wherein after step (c) and before the ribbons are scattered onto the surface in step (d) the plurality of ribbons are mechanically worked in a splitting step to split, lengthwise in a direction along the fibre direction, at least some of the plurality of individual ribbons formed in step (c) into respective two or more ribbons of smaller width, transverse to the fibre direction, as compared to the individual ribbons formed in step (c), wherein prior to the splitting step the ribbons have a width of from 8 to 44 mm and after the splitting step the ribbons have a width of from 1 to less than 20 mm, or wherein prior to the splitting step the ribbons have a width of from greater than 4 to up to 30 mm, and after the splitting step the ribbons have a width of from 1 to 10 mm;
• ii. assembling the plurality of layers as a stack;
• iii. locating the stack in a moulding area of a mould tool, the mould tool defining a peripheral edge of the moulding area, wherein the stack of layers is shaped and dimensioned to cover from 90 to 100% of the moulding area and a peripheral edge of the stack is located at or inwardly of the peripheral edge of the moulding area, the stack of layers defining a panel part;
• iv. applying a moulding pressure to an upper surface of the stack and causing the sheet moulding compound to flow and fill a mould cavity, defined by the moulding area, of the mould tool;
• and
• v. solidifying the resin to form a moulded part from the moulding material, wherein the moulded part includes a panel portion formed from the panel part.

A method of moulding a moulding material to form a moulded part of fibre-reinforced resin matrix composite material, the method comprising the steps of:

• i. providing a plurality of layers of sheet moulding compound, each layer comprising a plurality of ribbons randomly distributed across the plane of the respective layer and at least partly coated by a resin, each ribbon comprising a bundle of mutually aligned carbon fibres and being randomly oriented within the plane of the layer, in each layer of sheet moulding compound the ribbons are distributed to cover less than 100% of the plane of the layer, wherein each layer of sheet moulding compound is formed by the following steps:
• (a) providing an elongate tow of carbon fibres;
• (b) spreading the tow of carbon fibres to form an elongate ribbon;
• and (c) cutting the elongate ribbon transverse to the length of the elongate ribbon to form a plurality of individual ribbons;
• (d) scattering the plurality of ribbons onto a surface to form a layer of the plurality of ribbons which are randomly distributed across the plane of the layer;
• and (e) coating a resin onto the plurality of ribbons to form the layer of sheet moulding compound, wherein after step (c) and before the ribbons are scattered onto the surface in step (d) the plurality of ribbons are mechanically worked in a splitting step to split, lengthwise in a direction along the fibre direction, at least some of the plurality of individual ribbons formed in step (c) into respective two or more ribbons of smaller width, transverse to the fibre direction, as compared to the individual ribbons formed in step (c), wherein prior to the splitting step the ribbons comprise from 10,000 to 50,000 carbon fibres and after the splitting step the ribbons comprise from 2,000 to 20,000 carbon fibres;
• ii. assembling the plurality of layers as a stack;
• iii. locating the stack in a moulding area of a mould tool, the mould tool defining a peripheral edge of the moulding area, wherein the stack of layers is shaped and dimensioned to cover from 90 to 100% of the moulding area and a peripheral edge of the stack is located at or inwardly of the peripheral edge of the moulding area, the stack of layers defining a panel part;
• iv. applying a moulding pressure to an upper surface of the stack and causing the sheet moulding compound to flow and fill a mould cavity, defined by the moulding area, of the mould tool;
• and
• v. solidifying the resin to form a moulded part from the moulding material, wherein the moulded part includes a panel portion formed from the panel part.