Other

National University of Singapore

Yoke San Wong

Li Lu

En Tang Kang

Kah Bin Lim

Yoo Sang Choo

Xuan Wang

Gnian Cher Lim

Ying Hsi Jerry Fuh

YueFeng Yu

Ying His Jerry Fuh

HongBin Cheng

YaXin Tang

JiHuan Luo

Yeh Ching Andrew Nee

XiangLin Zhang

Jerry Ying Fuh

Tetsuo Miyazawa

Han Tong Loh

Ying Kit Chew

Chee Leong Teo

Kuak Choi Lealic Lim

Zhenda Chen

YunGan Wang

XinHua Wang

This invention presents the process of direct laser casting of copper alloys: Cu&mdash;X (where X&equals;Ni, Fe, W;) and their composites Cu&mdash;Y and Cu&mdash;X&mdash;Y (Y&equals;WC, TiC, Ti&plus;C) from powders prepared using mechanical mixing and ball milling processes. Since the metallic powder is combined with a low melting point Cu metal, which has good thermal and electrical conductivity, the combination allows the powder mixture to be melted by CO laser and re-solidified into a part with good mechanical properties and conductivity. The laser casting process for the Cu-based in-situ formation and the material systems formed using the said method have been developed. The process can be used to fabricate complex three-dimensional objects by multi-layer overlapping and the material systems can be used to build rapid tooling due to the properties of good thermal conductivity and low wear rate.

Method of laser casting copper-based composites

A method for determining the areas of resin to be cured in an optical stereolithography process for rapid prototyping using sequential laser curing of layers of a resin having a selected thickness to produce a desired shape of cured resin. The method includes the steps of generating a computer model of desired shape and dividing the model into layers of thickness equal to the thickness of the layers each defining an area of resin to be cured. A set of layers including and sequentially adjacent an intermediate layer is selected and the areas in the intermediate layer of resin which would be oversized by laser curing of layers later in the curing sequence is determined. The 2-D layer data used to build a 3-D model is modified to compensate for the oversizing and the steps repeated by sequentially selecting sets of layers to include substantially all of the layers as the intermediate layer. The sets are sequentially selected with each subsequent set having the intermediate layer being the layer adjacent the intermediate layer of the previously selected set. The first selected set includes the first layer to be cured and the sequential subsequent sets respectively include as the intermediate layer the subsequently cured adjacent layer.

Method for determining resin curing areas in an optical stereolithography process

A computer-controlled apparatus and method for producing metallic parts by laser melting selected regions of a layer(s) of metal powder at a target area are disclosed. The system includes devices for preheating and maintaining a relatively high temperature, e.g. 400&deg; C., of the metal powder so as to join the metal powder together with relatively low laser power, e.g. a 200W CO laser. A major powder depositing mechanism with a scraper and a depositing system for a secondary powder are included in the apparatus that allows the powders to be delivered to the target area for selective melting. The metal powder is preheated at either a dispensing cylinder or the target area through thermal conduction and/or is also heated by a heating plate positioned above the platform through radiation. The corresponding machine structures, such as a motion system and a working chamber, are designed to be able to withstand and operated under the high temperature environment.

Method and apparatus for creating a free-form three-dimensional metal part using high-temperature direct laser melting

Growing community of inventors

Singapore, Singapore

Yoke San Wong