Vacuum laminating, infusion,
VARTM, VIM, LRTM

The product manufacturing takes place with closed moulds. The first step is to apply the Gelcoat (by hand or SPRAY), just like in the hand lay-up method.
The next stage is to stack the structural layers (glass mats, technical fabrics, synthetic mats, sandwich mats, coremat, rovicore, etc.) and possible reinforcements and adaptation kits in the mould.

The mould is sealed - a vacuum is generated

Afterwards, the mould is closed; it can also be sealed using a special polyester-glass laminate membrane (punch) or a plastic or silicon bag membrane.
Irrespective of the method selected, the primary goal is to ensure the mould’s tightness (a hermetic seal). Once the mould is sealed, a vacuum is generated inside it, after which it is filled with the appropriate resin through special channels or openings. Resin injection and carrier material filtering take place due to the vacuum created.

Advantages of this method

  • relatively low production start-up cost compared to RTM technology (but higher than commencing hand lay-up production),
  • the method is cost-effective for medium-volume orders,
  • the products can be fitted with additional adaptation kits and/or reinforcements (metal adaptation kits, PU foams, spacers, etc.),
  • good venting in the laminate structure,
  • possibility of producing parts with a variable wall thickness
  • low emissions of volatile substances into the environment.

Compared to the hand lay-up method:

  • superior quality and uniform product structure,
  • higher density and better mechanical properties,
  • higher glass content and improved product durability,
  • smooth surface on both sides,
  • improved process efficiency.

The method for making parts
with less complex shapes

Apart from the technological limitations (e.g. technological radii, wall inclination), this method can generally be used to make parts with less complex shapes. Further limitations are also caused by the need to ensure a hermetic seal for the mould, as well as considering the special resin injection channels when designing it.

  • increased material waste due to the presence of resin flow channels,
  • greater material thickness accuracy compared to hand lay-up lamination
  • limited possibility of making changes to the mould.