Closed Mold Fiberglass Processing

There are multiple different methods to closed molding to fit almost any need or requirement. Closed molding reduces waste and scrap, and allows for more precise tolerances. Closed molding also allows for a cosmetic “B” side of your part.

Light RTM

Light RTM is a closed molding process that utilizes vacuum pressure. Resin is infused into the cavity preloaded with glass mat using negative cavity pressure.     Some of the benefits of this type of fiberglass manufacturing include: increased cycle times, parts that can be produced to very close tolerances, parts that are smooth on both sides, and can be used for low and high production quantities.

  • Moderate Production Rates (1,000 - 5,000 parts/yr)
  • Consistent Dimensional Control
  • Tolerances within +/- 0.500 mm
  • Large Structurally Reinforced Parts
  • A-side surface - gelcoat or primer
  • Two-Sided Finish
  • Minimum Radius – 6mm (.236 in)
  • Minimum Draft – 3 degrees
  • Minimum Thickness – 3 mm (.118 in)
  • Maximum Thickness – Varies with use of foam/balsa cores
  • Typical Reinforcement Loading – 30 – 35%

CCBM

Closed Cavity Bag Molding is a Light RTM molding process using a soft and flexible silicone “B” side mold instead of a traditional rigid mold. Some of the benefits of this type of fiberglass manufacturing include: Higher glass content, lower tooling cost, increased cycle times, parts that are smooth on both sides, and can be used for low and high production quantities.

  •  Low to Moderate Rates (250 – 5,000 parts/yr)
  • Consistent Dimensional Control
  • Tolerances within +/- 0.500 mm
  • Structurally Reinforced Parts
  • A-side surface - gelcoat or primer
  • Two-Sided Finish
  • Minimum Radius – 6mm (.236 in)
  • Minimum Draft – 1 degrees
  • Minimum Thickness – 3 mm (.118 in)
  • Maximum Thickness – Varies with use of foam/balsa cores
  • Typical Reinforcement Loading – up to 60%

RTM

Resin Transfer Molding, is a low positive cavity pressure, closed molding process. This means that RTM parts are made by injecting liquid resin and catalyst into a closed mold cavity containing dry fiber reinforcements. Some of the benefits of this type of fiberglass manufacturing include: fast cycle times, parts that can be produced to close tolerance requirements at varying thicknesses.  The molded panels are smooth on both sides, and can be used for low and high production quantities.

  • Moderate Production Rates (1,000 - 5,000 parts/yr)
  • Consistent Dimensional Control
  • Tolerances within +/- 0.250 mm
  • Large Structurally Reinforced Parts
  • A-side surface - gelcoat or primer
  • Two-Sided Finish
  • Minimum Radius – 3 mm (.118 in)
  • Minimum Draft – 3 degrees
  • Minimum Thickness – 3 mm (.118 in)
  • Maximum Thickness – Varies with use of foam/balsa cores
  • Typical Reinforcement Loading – 30 – 35%

LCM

Liquid Compression Molding (commonly referred to as Cold Molding) is a high pressure closed molding process. LCM is a method in which the glass fabric is placed in an open mold cavity. Once the glass has been placed, the fabric is subjected to a light resin coat. The mold is then closed with a top plug in which pressure is applied to force the resin and glass material into contact with all mold areas. Heat and pressure are maintained until the part has been cured. Some of the benefits of this type of fiberglass manufacturing include: extremely fast cycle times, parts that can be produced to very close tolerances, parts that are smooth on both sides, and typically used for high production quantities.

  • High Production Rates (up to 20,000 parts/yr)
  • Consistent Dimensional Control
  • Tolerances within +/- 0.250 mm
  • Large Structurally Reinforced Parts
  • Two-Sided Finish
  • Minimum Radius – 3 mm (.118 in)
  • Minimum Draft – 3 degrees
  • Minimum Thickness – 3 mm (.118 in)
  • Maximum Thickness – 6 mm (.236") cores not recommended
  • Typical Reinforcement Loading – 30 – 35%