System Design And Materials Research Of Three Dimensional Printing

Power Bed and Inkjet Head 3D Printing(3DP) is a kind of additive manufacturing technology, which owns outstanding advantages as low cost, high manufacturing speed and full color manufacturing, has a wide application prospects in modeling and bio-manufacturing. However, compare to SLS,SLM,FDM and SLA, this technology has a lower maturity, material system need to be improved. Regards to this, a prototype of 3DP and two kinds of material systems have been designed and studied, forming principle and effect have been initial verified.Choose thermal inkjet print-head HP802 as inkjet part and design prototype. Mechanical parts are assembled by frame, powder feeding system, dusting system and print-head. Use PCI control board and single chip microcontroller to control the movement of print-head(X axis), ball screw(Y axis) and chambers(Z axis). The prototype owns advantages as high system openness, low cost and high stability.Design material system use plaster as main body. Choose deionized water, polyethylene glycol, polyvinyl pyrrolidone and CTAB to compose as ink, choose plaster, polyvinyl alcohol, hydroxyethyl cellulose and nano-silica to compose as powder. Manufactured parts have shrinkage of 2% in parallel and perpendicular direction to injection, and shrinkage of 3% in diagonal, slightly better than commercial equipment. Bending experiments shows the initial bending strength is 1.96 MPa and final bending strength is 8.77 MPa after infiltrating silica sol, mechanical properties close to commercial equipment. Morphology under SEM shows the ratio of polymer binder to water is too high, affecting the growth of hydrated hemihydrate, causes low strength; silica sol filling the void parts and reacted hydrate growth causes the improvement of strength.Design material system use polystyrene as main body. Choose deionized water, polyethylene glycol, polyvinyl pyrrolidone and CTAB to compose as ink, choose polystyrene and polyvinyl alcohol as powder. Study the effect of component ratio to part property. Results show that the powder formed by 25% PVA and 75% PS has the best property, shrinkage of 1.7% and initial bending strength is 0.26 MPa. After infiltrating wax, final bending strength is 3.38 MPa. TG test shows that the final part leaves no remains under 500℃. Part property fit the demands of investment casting.Above all, a prototype of 3DP owns advantages as high system openness, low cost and high stability has been designed; a material system of plaster fit the demands of modeling and a material system of polystyrene fit the demands of investment casting have been designed and studied. This paper provides specific programs and theoretical guidance of related mechanical design and materials research, is useful for future material study.