Research On Fused Deposition Modeling Technology Of Wood Plastic Composites

Wood Plastic Composites (WPC) is an environmental composite material which is developing rapidly in recent years, it uses wooden flour and plastic as the main raw material. This kind material has advantage of waterproof, moistureproof and no craze, and it is widely used in construction and decoration.Rapid Prototyping (RP), a new kind of molding manner appeared in the 1980s,has been paid greatly attention since appear, and many countries have been researching on the new technology and new materials of rapid prototyping. But at present rapid prototyping materials are still very expensive, which restricts technical popularization.In this paper, WPC is used in Fused Deposition Modeling (FDM), a kind of RP, and the FDM technology of WPC is put forward. The main research includes the improvement of the FDM mechanical system of WPC, the filling algorithm and the speed matching between screw rotate speed of nozzle and scanning filling speed.According to the properties of WPC, the RP mechanical system is improved. The modified system includes two nozzles, spin nozzle extrusions filamentous material, and rectangle nozzle extrusions rectangular chip material. The nozzles work in turn, and the efficiency is improved. Granular material is used to simplify the structure of feeding device.For using two different types of nozzles to fill the slice, there is no appropriate filling algorithm. Based on the existing algorithms applied, this paper gives a new filling algorithm for FDM of WPC. By mathematical method, the slice is divided into three parts, bias part, rectangular part and fragment part. As working, the rectangle nozzle fills the rectangular part and spin nozzle fills the fragment part and bias part.In the study of speed matching, the nozzle is considered to be a small screw extruder, and the mechanism of conveying and extrusion of WPC in the nozzle is explained according to the theory of extruder. According to rheology theory, flow channel of nozzle is thought to be made up of several paragraphs of simple geometric shapes flow, and the pressure drop of nozzle which molten WPC flow through is calculated, and the mathematical relationship between screw rotation speed and scanning filling speed is illustrated.