RIM Terminologies

Explanation of terms:

RIM: Reaction Injection Moulding:

It is a variation of the basic injection moulding process involving high pressure impingement (impact) mixing of two or more reactive thermoplastic or thermoset liquid component (either cold or warm) in a mixing head. After mixing, the liquid stream is injected into a closed, warm mould, at low pressure, where the reaction continues and the mixture solidifies. The finished parts can be cellular or solid elastomer, with a wide range of hardness and modulus.

LIM: Liquid Injection Moulding:

It is another term used for the same process – RIM

HPIM: High Pressure Impingement Mixing:

It is used especially with urethanes, which is a most important one in the overall moulding process.

INJECTION MOULDING in FRP

                     1.         Material:

                     2.         Polyester and Epoxy reinforced compounds with maximum reinforcement fiber length of approximately ½” are used.

                     3.         Process:

                     4.         It is similar to the Injection moulding of thermoplastic. However the barrel and screw or plunger is kept at relatively lower temperature and the material is injected into a mould kept at 150-175⁰C.

                     5.         Advantages:

a.       High production rates for very complex parts with almost complete automation.

Flash is minimal because parts are injected into a closed mould and thus post mould trimming is kept to a minimum.

LIST OF PROCESSING TECHNIQUES IN FRP

PROCESSING TECHNIQUES USED FOR REINFORCED PLASTICS:

1.      HAND LAY UP TECHNIQUES

2.      SPRAY UP TECHNIQUE

3.      MATCHED DIE MOULDING

4.      PREMIX MOULDING (BMC MOULDING)

5.      INJECTION MOULDING

6.      CONTINUOUS LAMINATION

7.      PULTRUSION

8.      RESIN TRANSFER MOULDING (RTM)

9.      FILAMENT WINDING

10.  SANDWITCH STRUCTURE PROCESSING

11.  FOAM (ELASTIC) RESERVOIR MOULDING (FRM OR ERM)