Patent ID: 8647543

Claim:
A process for forming a polymer composite article comprising: feeding composite polymer pellets comprising a thermoplastic polymer and reinforcing fibers into a barrel of an injection molding system, wherein the injection molding system comprises a screw contained within the barrel, wherein the screw has a compression ratio of less than 2.5:1, wherein the screw has a rotational speed that is less than 70 rpm, and wherein the barrel has a back pressure that is less than 2,000 psi, and wherein the screw further comprises a first section containing flights and a second section containing flights downstream from the first section, and wherein a check valve separates the first section from the second section; heating the thermoplastic polymer to a molten state; feeding a blowing agent into the barrel; injecting the thermoplastic polymer, reinforcing fibers, and blowing agent into a molding cavity; and producing a cellular fiber reinforced polymer article, wherein the reinforcing fibers in the reinforced polymer article have an average fiber length greater than 1.2 mm, wherein at least 10 percent by volume of the reinforcing fibers have a length greater than 3 mm.