Direct Long Fiber Thermoplastic Molding

Direct Long Fiber Thermoplastic Molding (D-LFT)

DLFT Molding Process IllustrationLong fiber thermoplastic molding is a newer technology where thermoplastic material is directly compounded with long glass fibers (rovings) and then molded in one operation. Glass fibers of 1/2” (12 mm) up to 2" (50 mm) in length give much higher stiffness, strength and toughness than the 1/8“ (3 mm) fibers that are commonly used.

The advantage of D-LFT is the ability to control the length of the fiberglass being mixed into the thermoplastic pellets via an extruder.  The process enables control of the compound properties, and therefore the part, with high consistency.

D-LFT process is generally a cross between injection and compression molding. Typically, the compound is mixed in the barrel of the injection machine where the material is heated (425˚F). The tool is run cold, to help cool or freeze the thermoplastic material placed in it. This is a cooling process "in the tool," rather than an exothermic reaction as with a true thermoset material like SMC.  As a thermoplastic, the stiffness is good (typically 40% glass) but the material will soften and lose modulus with heat exposure.

  • Excellent mechanical properties and stiffness-to-weight ratio
  • Polypropylene is most common for the thermoplastic, but others such as PET or PBT can be used to impart various properties to the part. We can help you select the most advantageous thermoplastic for your application.
  • Normally this process is well-suited for 10,000 to 40,000 parts per year*

* Volume recommendations are averages and provided only as a general guideline.  Actual volume efficiencies are a more complex matter requiring detailed statistics about the part to be manufactured.

Resource Type Description
Mass Reduction With Value-Engineered Composites PDF Light-weighting (mass reduction) using advanced composite materials.
Technical Design Guide for FRP Composite Products and Parts PDF Fiberglass (FRP) composite materials and processes are explained in detail. This design guide outlines various selection criteria with helpful technical data and comparisons to alternative materials.
Guide for Selecting Best FRP Composite Process PDF Guidelines for Selecting the Best FRP Composite Process for Your Project

Snapshot Guide: Shapes, Uses and Considerations

Weatherable color, low weight, low cost. For tough parts that require durability and flexibility with good surfaces.