Manufacturing processes

Ilium Composites products are versatile, feature rich and provide unique benefits to a broad range of composites manufacturing processes. With a strong focus on closed mold applications, Ilium’s materials lead the way in high-tech manufacturing processes.


Light Resin Transfer Molding, or L-RTM, is a closed mold process, often using composite molds. The two mold faces are closed and sealed under vacuum. Resin is drawn into the resulting cavity under vacuum and assisted by a low pressure resin injection pump for fast saturation of the reinforcement.

Process features of L-RTM:

  • High productivity with fast cycle times versus open mold
  • Reduced labor costs
  • Cosmetic surfaces on both sides of part
  • Enhanced dimensional stability
  • Improved process control
  • No VOC emissions
  • Improved factory working conditions

Features and benefits:

  • Improved fiber print and part aesthetics
  • Inherent protection from blistering and chemical attack
  • Better thermal cycling of the finished part
  • Increase in inter-laminar shear strength

Hand lamination

Hand lamination involves manually saturating any reinforcement material with resin in a mold. The reinforcement material (mat) is placed into the mold, resin is added and the operator can use brushes and rollers to wet the mat, remove air voids and compact the laminate.

Features and benefits:

  • Incorporated surface veil improves surface finish and protection from the environment
  • Easy removal of air versus traditional CSM
  • Mechanically fixed fibers ensure consistent and predictable part thickness
  • Tighter tolerance allows for lighter, lower cost parts

Continuous lamination

Continuous lamination is an automated process where reinforcements are impregnated with resin and compressed in a conveyor system to the desired thickness and cured in a heating zone. An efficient way to produce flat panels cost effectively, it is used for truck and trailer floors and side walls, cladding panels, sky lights and other flat surfaces.

Features and benefits:

  • Incorporated surface veil improves surface finish and protection from the environment
  • No chemical binder provides faster wet out
  • The mat will not break down or stretch when exposed to styrene for extended periods
  • Mechanically bonded and fixed mat provides higher pulling strength
FLEXmat amplify


Pultrusion is a continuous process for manufacturing composite profiles and structural shapes in which glass fiber reinforcements are saturated in resin and pulled through a heated die where the part is formed and cured.

Features and benefits:

  • Conformability in thin complex profiles
  • Incorporated synthetic surface veil
  • High processing tensile strength
  • Provides structural strength in the transverse direction


  • Lighter weight reduces cost
  • Loft of material better fills die cavity
  • Corrosion resistant
  • Resin-rich surface improves
  • UV resistance
  • Multi resin compatibility in a single product (polyester, vinyl ester, epoxy, polyurethane, phenolic)
FLEXmat amplify

Wet compression molding

Wet compression molding is a closed mold process by which reinforcements and selected resins are placed in an open mold cavity and then a heated metal counter mold is applied under very high pressure to achieve the finished part. It allows fast production of parts and used in very high series volumes of basic geometry parts.

Features and benefits:

  • Excellent formability
  • Material can be preformed first
  • Inherent blister and environment protection

Vacuum Infusion & silicone bag molding

Vacuum infusion is a closed mold process whereby a disposable or re-useable silicone membrane is applied after laying reinforcement in the mold. The membrane is sealed and vacuum pressure is applied in the cavity, allowing the vacuum to pull resin through the cavity and evacuate air from the part. The tooling costs are low and typically the process is used for low series volumes of parts where close tolerances and high fiber ratios are needed.



Ilium’s binder free technology provides a perfect solution for tooling as the integrated surface veil provides an ideal first layer with excellent aesthetics requiring less polishing. Epoxy tools benefit even more as the binder free technology provides easy and fast wet out of the mat.

Features and benefits:

  • Easier preparation of mold surface
  • Lower cost mold preparation
  • Compatible with multiple resin systems for faster production of epoxy tools