【正文】 essing and netshape materials processing in a single step. The general concept involves converting a mold design described by a CAD file to a tooling master using a suitable rapid prototyping (RP) technology such as stereolithography. A pattern transfer is made to a castable ceramic, typically alumina or fused silica. This is followed by spray forming a thick deposit of tool steel (or other alloy) on the pattern to capture the desired shape, surface texture and detail. The resultant metal block is cooled to room temperature and separated from the pattern. Typically, the deposit’s exterior walls are machined square, allowing it to be used as an insert in a holding block such as a MUD frame [5]. The overall turnaround time for tooling is about three days, stating with a master. Molds and dies produced in this way have been used for prototype and production runs in plastic injection molding and die casting.An important benefit of RSP Tooling is that it allows molds and dies to be made early in the design cycle for a ponent. True prototype parts can be manufactured to assess form, fit, and function using the same process planned for production. If the part is qualified, the tooling can be run in production as conventional tooling would. Use of a digital database and RP technology allows design modifications to be easily made.Experimental ProcedureAn aluminabase ceramic (Cotronics 780 [6]) was slurry cast using a silicone rubber master die, or freeze cast using a stereolithography master. After setting up, ceramic patterns were demolded, fired in a kiln, and cooled to room temperature. H13 tool steel was induction melted under a nitrogen atmosphere, superheated about 100176。C, quenched in air or oil, and carefully tempered two or three times at 540 to 650176。 Sons, NY, p. 14, 1989.[2] Rapid Prototyping amp。C, and air cooled. Conventionally heat treated H13 was austenitized at 1010176。然而，不是總能得到可靠預(yù)測(cè)的。典型的奧氏體化溫度大約是1010176。％。計(jì)算出的從噴嘴噴出的或小（～30微米）或大（～150微米）的凝固體分?jǐn)?shù)，如圖2b。中央塊狀直徑被確定的56微米為插補(bǔ)尺寸的50％的累積頻率。用INEEL（國(guó)家工程與環(huán)境實(shí)驗(yàn)室）開(kāi)發(fā)的一維計(jì)算機(jī)章程用來(lái)評(píng)價(jià)多相流在自由射流噴嘴的表現(xiàn)。常規(guī)熱處理H13鋼的是在1010176。H13工具鋼是由在內(nèi)部設(shè)計(jì)和建造的溫度約100176。在一個(gè)機(jī)器工作的情況下，加工總周轉(zhuǎn)時(shí)間大約是3天。本文介紹了噴射成形技術(shù)對(duì)于生產(chǎn)H13工具鋼的注塑模具和沖壓模具的應(yīng)用，以及低溫?zé)崽幚硭鶐?lái)的好處。注塑模具的費(fèi)用因規(guī)模大小和復(fù)雜程度，從大約1萬(wàn)美元到30萬(wàn)美元以上不等，并有3到6個(gè)月的制造周期。這一加工出所希望的零件形狀（模芯和型腔）的過(guò)程包含鍛制工具鋼或者金屬鑄件毛坯，增加冷卻通道、排氣孔和其他機(jī)械性能，接著是磨。翻譯質(zhì)量良。這種方法把快速凝固加工和網(wǎng)狀材料加工結(jié)合在一個(gè)單步執(zhí)行。制造周期通常大于40周。從CAD軟件到高精度工具鋼所使用的一個(gè)合適的快速原型（RP）技術(shù)解釋了一般概念上所涉及模具設(shè)計(jì)轉(zhuǎn)換，如立體平板印刷。真正的原型零件用相同的生產(chǎn)加工計(jì)劃可以被制成預(yù)定形狀、尺寸和性能。對(duì)于延伸性和硬度的要求。在室溫下，微硬度測(cè)量使用的是平均每10微刻度讀數(shù)的M型維氏硬度測(cè)試儀。該章程還包括一個(gè)允許液滴冷卻和升溫的非平衡凝固模型。圖1 噴射H13工具鋼的粒子聚集頻率和累積頻率分布圖2給出了在射流噴嘴里多相流場(chǎng)速度的計(jì)算結(jié)果（圖2a），和H13工具鋼的凝固體分?jǐn)?shù)線(xiàn)（圖2b）。這是相對(duì)靈活的，澆注陶瓷材料的模式將取代難以令人滿(mǎn)意的常規(guī)金屬鑄造過(guò)程。這種鋼以低含碳量（％）來(lái)提高韌性，以中等含鉻量（5％）來(lái)提供良好的抗高溫軟化性，以1％的硅含量來(lái)改善抗高溫氧化性，以少量鉬和釩（約1％）形成穩(wěn)定的碳化物來(lái)提高耐磨性[8]。商業(yè)用的鍛造鐵素體工具鋼因?yàn)殇撹F廠(chǎng)的鑄塊慢慢冷卻形成粗糙碳化物而不能被沉淀硬化。參 考 文 獻(xiàn)[1] R. G. W. Pye, Injection Mould Design, John Wiley amp。s basic numerical technique solves the steadystate gas flow field through an adaptive grid, conservative variables approach and treats the droplet phase in a Lagrangian manner with full aerodynamic and energetic coupling between the droplets and transport gas. The liquid metal injection system is coupled to the throat gas dynamics, and effects of heat transfer and wall friction are included. The code also includes a nonequilibrium solidification model that permits droplet undercooling and recalescence. The code was used to map out the temperature and velocity profile of the gas and atomized droplets within the nozzle and free jet regions.Results and DiscussionSpray forming is a robust rapid tooling technology that allows tool steel molds and dies to be produced in a straightforward manner. Each was spray formed using a ceramic pattern generated from a RP master.Particle and Gas BehaviorParticle mass frequency and cumulative mass distribution plots for H13 tool steel sprays are given in Figure 1. The mass median diameter was determined to be 56 μm by interpolation of size corresponding to 50% cumulative mass. The area mean diameter and volume mean diameter were calculated to be 53 μm and 139 μm, respectively. Geometric standard deviation, sd=(d84/d16)1