The polymers which belong to thermosets field supplies to industries several different possible application processes. Four processes have been chosen for the project:

  • Hand lay-up,
  • RTM,
  • Infusion,
  • Vacuum compaction.


All these processes can be defined as follows:

Hand Lay-Up – Open moulding

Coating of the mould by successive layers of resin and reinforcement (manually) or a mixture of both (spray-up).

Wetting out and removal of entrapped air with rollers and brushes by an operator.

Closed Moulding - RTM & RTM Light

Laying up of divers dry reinforcement material inside the mould.

Clamping shut of the upper mould and injection of the resin into the mould with a machine.

Vacuum assist can be used to enhance resin flow and degassing of the resin.

Infusion – Closed moulding

Positioning of the dry reinforcement into the mould as well as surface drainage.

Covering over with an airlight plastic film which is used as the upper mould.

A vacuum is applied to consolidate the laminate and the resin is pulled into the mould.

Vacuum compaction

The reinforcements and the resin are applied in the mould and positioned.

Closing of the upper mould or silicone bag by vacuum.

A vacuum is then created to evacuate surplice resin.

Assets and drawbacks of the application processes

We joined together the assets and the drawbacks of the four application processes mentioned into the table here under by adding economic, environmental criteria but also skill and productivity criteria.

To these four-application processes, it would be added the pultrusion and the filament winding, the BMC, the SMC and the prepreg; but these additional applications are dedicated to specific activities, and they request mass production.


Hand lay up

Open moulding

Closed moulding


Infusion Vacuum compaction



Cost of the tools ★★★★ ★★ ★★
Cost of consumables ★★★★ ★★★ ★★ ★★★

Production rate

(small production run)

★★★★ ★★★ ★★ ★★★

Production rate

(mass production)

★★ ★★★★ ★★ ★★★

Type of parts

(size and complexity)

★★ ★★ ★★★★ ★★★★
Coating of the mould time ★★★ ★★ ★★ ★★
Demoulding time ★★ ★★★★ ★★ ★★★
Specific need in resin ★★★★ ★★ ★★ ★★
Final parts aspect ★★★ ★★★★ ★★★ ★★★★
Fibre ratio ★★ ★★★ ★★★★ ★★★★
Skill of the operator ★★ ★★★ ★★★ ★★★
Environnemental considerations ★★★★ ★★★★ ★★★★