Direct compounding and forming of long glass fibre thermoplastics (D-LFT) are being assembled and ready for development from structural parts of automobiles to outer panels of automobiles. This leap also includes the transformation of D-LFT Composite Pillar materials from polyolefins to styrene-based thermoplastics. The compression molding of large thermoplastic composite body panels is said to have successfully passed the sub feasibility study. The next step will be the assessment of the rear lid, door and roof with class a surface. At the same time, D-LFT has also made new achievements in the application of structural automotive parts such as chassis and hood. They include adjustable die to determine blank thickness, adding reinforcing fibers to randomly crushed glass blanks, and using nylon as D-LFT substrate in engine hood. The test of large D-LFT body panels starts with injection molding and compression molding, and the two molding passes the impact test. Compression parts show 50% higher impact strength than injection parts, and compression is probably the method of choice for large parts. One advantage of large D-LFT parts is that reinforcing fibers or decorative surface films can be easily embedded in the die. When the material is pressed, it will not flow far, so that the fiber will be stretched less and the deformation will be smaller. The compression test of large D-LFT body panels started two years ago by Dieffenbacher, Germany, and has been in progress, and is developing cooperation with BASF and other companies. For these applications, BASF spent five years developing new materials and lacquer films.

The new achievement of Dieffenbacher in D-LFT achieving grade a finished products is the addition of broken fibers.

Dieffenbacher's typical D-LFT method is to pull continuous glass roving into a twin-screw extruder, cut the roving by the screw, and gently mix them into the pre-melted polymer. But the outer car body needs better fiber dispersion to prevent printing on the surface of class a components. So now the fibers are cut dry and fall on the feeding chute. The feeding device quantitatively adds the fibers to a curtain melt extruded by the slot die. Such a curtain melt carries fibers into second extruders for mixing. This opens the fiber bundle, so all kinds of filaments are better dispersed. New materials are also needed for the testing of automobile body exterior panels, especially the hot-formed PFM (no-paint film forming) skin developed by BASF. PFM skin can be colored and textured, eliminating the need for two processing. PFM skin is hot formed, and then PFM skin is formed with 20% - 30% glass reinforced ABS or SAN using resins developed by BASF for these purposes. Because the body panel is likely to be assembled with steel components, and styrene-based materials have lower thermal expansion coefficients than many other thermoplastics, styrene-based materials are used in PFM membranes and supporting composites. The cycle time for forming these panels with PFM skin is 30-40 seconds, compared with 60 seconds for thermosetting SMC components. The D-LFT body panels are being considered as the replacement parts of the 2005 cars and the original parts of the 2006 and 2007 cars. The first step will be the car roof assembly. A D-LFT exposed component will appear at the end of 2005. It will not use decorative films or grade a products. It will have a bit of grit, made of glass reinforced PP. It will appear in the lower part of the rear car cover in Europe. Dieffenbacher has developed a die with adjustable holes for D-LFT structural components, which can selectively press thick and thin points into the blank, so as to increase the strength of specific areas, while minimizing the overall material consumption. This is also a method used by other D-LFT technology providers. Dieffenbacher's adjustable die head uses a servo hydraulic cylinder on the lower die lip with a sensor to display the width of the opening.

Dieffenbacher die changes the thickness from 2 mm to more than 30 mm, although the thickness range of most test components is 5-15 mm. The shaped blank material requires smaller compression force to distribute the material in the mold. Because the extruder runs at a steady speed, the thin plate comes out faster and the thick plate comes out slower. Computerized on-line control matches the speed of the conveyor with the thickness of the conveyor. A billet cutter is used to cut the billet between the two belts. The second conveyor belts are running on the side, so they can shape the blank for two different moulds. Also for structural components, Dieffenbacher developed an automated process using manipulators and needle fixtures to insert woven and non-woven fiberglass reinforcements into specific parts. The front end plate of BMW is an example of thermoplastic compression molding with locally continuous fiber reinforcements. It uses strip Twintex PP/glass woven fibers, Twintex containing 60% glass is placed on the upper bearing edge of the component, and non-woven glass ropes are used where there are ribs. Twintex inserts are preheated in an infrared heater before being stacked on top of the D-LFT blank. Dieffenbacher plans to study the feasibility of combining Twintex reinforcement with PFM decorative film. The film will first be put into the mold, followed by the D-LFT composite blank, followed by the Twintex fiber. In addition, D-LFT of nylon 66 is being considered by at least one European car manufacturer for use in heat-resistant components to replace SMC in engine cases.