Wanhua Zhao

Investigation of the overlapping parameters of MPAW‐based rapid prototyping

Purpose – To fabricate fully dense components with low costs, a rapid prototyping (RP) system based on micro‐plasma arc welding (MPAW) was developed. The appropriate process parameters were investigated to build the parts with good mechanical properties and surface smoothness.Design/methodology/approach – A simplified overlapping model between deposited tracks was established to investigate the relationships among the overlapping parameters, such as the ratio of width to height of the deposited track cross‐section (λ), scan spacing and overlapping ratio. Some ER308L stainless steel parts were built by different overlapping parameters, and the surface smoothness, tensile strength and elongation of the parts were tested.Findings – The overlapped surface smoothness, tensile strength and elongation of the parts built with larger λ were better than those built with smaller λ. The longitudinal tensile strength and elongation of the parts were better than the transverse data.Research limitations/implications – T...

A novel stereolithography technology with conventional UV light

Stereolithography (SL) is a kind of rapid prototyping technology which uses the laminate manufacturing to fabricate parts. With the development of RP, some new RP processes have boomed rapidly. Compact prototyping system (CPS) is a kind of novel stereolithography method which utilizes conventional UV light as the light source. After transmitting by optic fiber and focusing through lens set, the light is intensified and can be used to cure the photopolymer. Compared with the laser SL prototyping apparatus, this apparatus has unique characteristics on its driving system and light path system. Discusses the characteristics and corresponding consequences of the driving system and light path system, and analyzes the light energy distribution and the corresponding line shapes. Since each layer is constructed from a serial of lines, the scanning parameters, especially scanning speed and hatch gap, will influence the overall light intensity which determines the layer thickness, section shape and ultimately the prototyping accuracy. The driving system, due to the non‐uniform moving speeds, could cause the shape error of the lines. A light shutter, keeping the light only illuminating on resin surface within given curing areas, is employed to solve this deficiency.

Rapid development technique for drip irrigation emitters

This paper describes the rapid development process for emitter which is the key part in water‐saving irrigation device. The design of labyrinth‐channel in emitters, the generation of process‐oriented structural CAD model, the building of emitter prototype and its integrative experimental model based on RP are introduced in detail. The emitter prototypes can be directly applied to irrigation experiments and production practice, and hence the rapid development of drip irrigation emitters can be realized.

Development and research of vacuum coating system in SL

Purpose – The purpose of this paper is to show how to precisely control the liquid resin coating thickness in stereolithography (SL).Design/methodology/approach – A vacuum adsorption coating equipment and technology are developed to precisely control the liquid resin coating thickness in SL. Dual‐electrode device is used, so adsorption can be precisely controlled and the electrode polarization can be avoided.Findings – It turns out that the apparatus can control coating thickness effectively, and thickness uniformity is increased remarkably, which induces the standard deviation thickness decrease from 0.00547 to 0.00243u2009mm, and efficiency of rapid prototyping production increase by 53 percent.Originality/value – The paper demonstrates that the apparatus can control coating thickness effectively.

Study on the Process Parameters of MPAW-Based Rapid Prototyping

A direct metal RP (rapid prototyping) process based on micro-plasma arc welding (MPAW) is presented. The impact of R (ratio of width to height of the deposited track’s cross-section) on part quality is investigated. Taguchi method is adopted to analyze the effect of each process parameter on R, and the optimized process parameters are obtained. The results show that the quality of the parts with larger R is better than that with smaller R, and the peak current, duty cycle of pulse duration, wire-feeding speed, scanning speed and plasma gas flow rate all exert significant effects on R. The overlapped surface smoothness, tensile strength and elongation of the parts fabricated with optimized parameters are measured to show obviously better performances than those of the parts fabricated with ordinary process parameters.