RESIN INJECTION MOULDING orRESIN TRANSFER MOULDING

By: Prasad Mahajan

What is RTM?

Resin Transfer Moulding  is the process of producing composite components within a mechanically-clamped, rigid, normally two-part (cope, drag) mould.

The principle behind composite manufacture is the mixing of the reinforcement with resin+catalyst mixture and the solidifying it using heat and pressure into the net shape desired.

Step by step procedure:

Diagram:

Recommended for:

High strength-to-weight requirements.With very complex shape parts.For mid-volume production in the range of

200 to 5,000 parts per year.Gel coat can be employed for better finish

on both side surface.Usually considered an intermediate process

between the relatively slow spray-up with lower tooling costs and the faster compression molding methods with higher tooling costs.

Materials Options:

Resins: Generally epoxy, polyester, vinylester and

phenolic resins are used, although high temperature resins such as bismaleimides can be used at elevated process temperatures.

Fibres: Any stitched/woven fabric materials work

well like glass fibre ,carbon fibre, aramid. Some specially developed fabrics can assist with resin flow.

Advantages:High fiber volume laminates can be

obtained with very low void contents.Volatile emissions like styrene are

massively reduced.High repeatability can be achieved.The laminate thickness can be closely

controlled.Less dependent on the skills of the

operatorAutomation possible.Both sides of the component can have

good finish.Allows one to obtain even very complex

neat-shape parts.Can produce a very strong part.

Disadvantages: Matched tooling is expensive, and heavy in

order to withstand pressures. Unimpregnated areas can occur resulting in

very expensive scrap parts. Higher cycle times. Large sized components needs very heavy

and costly moulds. Can produce some thickness variation. Low productive.Not possible to determine whether the

reinforcement material is properly covered by the resin

Applications:In complex aircraft partsTrain seatsTruck panelsBoat hullsWind turbine bladesAerospace and automobile partsMedical compositesBathroom fixtures, car body,

helmet, etc.

Modification (Vacuum RTM):

Also known as RTM Light.Uses vacuum-clamped two part

(male/female) matched mouldLight weight mould designLower cost mouldCan provide good definition and

extra detail for upper moulded surface.

RTM Light:

Video :Resin Transfer Moulding.mp4