Page 65 - Template Tesis UTM v2.0

parts with only one good surface. Precise thickness control in the moulding is also

difficult to achieve. The advantages and disadvantages of the hand lay-up method are
as shown in Table 2.11.

Table 2.11 Advantages and disadvantages of hand lay-up method [71]

Advantages Disadvantages

• Design flexibility • The process is labor-intensive

• Large and complex items can be • Only one tooled (molded) surface is
produced obtained

• Minimum equipment investment is • Quality is related to the skill of the
necessary operator

• Tooling cost is low • It is a low-volume process

• The start-up lead time and cost are • Longer cure times required
minimal • The waste factor can be high

• Design changes are easily affected

• Molded-in inserts and structural
reinforcements

• Sandwich constructions are

• possible
• Proto-typing and pre-production

method for molding processes

• Semi-skilled workers are needed
and working training is minimal

Vacuum bagging composites are inexpensive technique to optimise process
controls, design refinements and improve material properties by imparting vacuum and

pressure. Resin Transfer Moulding (RTM) is a closed mould process where resin mix
is transferred via injection ports into the cavity to form composite parts. Hard tooling

of match and female moulds are required in this process to withstand pressure during

resin injection. Curing condition for the parts being fabricated via RTM highly
dependent on the product thickness, mould temperature and type of resin used.

36