【正文】 through a variable number of machines depending on its process plan, and it is very cyclic (LithographyEtchImplant). In a similar fashion to VLSI manufacturing, the execution system will have to cover the handling of partially built parts and intermediate planning takes full 3D geometric models as inputs and outputs process description that specifies contents and sequences of operations that are necessary to produce the input parts. The contents contain machineunderstandable codes for driving designated machines to perform desired operations where as sequences specify all possible orders of operations that are valid to manufacture the input parts.Basic planning steps involve determining building directions, deposing a part into manufacturable volumes (called singlestep geometry), representing these submodels in a structured format for allowing optimizing building sequences, depositing materials on each singlestep geometry, and shaping deposed entities. The goals of these tasks are to generate process plans that are of lowcost, highquality, highprecision, and fast turnaround time. We will first define the constituent of the additive/subtractive process: singlestep geometry.Additive/subtractive SFF processes involve iterative material deposition, shaping and other secondary operations. Each of such operations is associated with a part ponent or a deposed geometry, which together represent a final product. The characteristics of such deposed geometry (a set of singlestep geometries) are that all supports for its undercut features are previously built, and no interference should occur in depositing or shaping processes from the top with respect to the building direction. In other words, any ray cast along the growth direction should not intersect a singlestep geometry more than once.Operations associated with each singlestep geometry may include deposition with different types of material or machines, machining operations using CNC machines, or electrical discharge machining. Or it could be simple operations such as automatic insertion of prefabricated following describes issues related to automatic and optimal planning for additive/subtractive approaches are not dissimilar with other pureadditive SFF processes in determining building directions. However, there are some more issues to be considered for additive/subtractive processes:The number of deposed singlestep geometries reflects time for part building. In a typical additive/subtractive process, shaping operations usually need deposited materials to be conditioned (in the case of plastics, cured/hardened。 Ramos 1996。 較新的處理走出研究實(shí)驗(yàn)室正在使用的工程材料（硬質(zhì)金屬，陶瓷等），并結(jié)合加法和減法的材料，作為一種更精確的方式來(lái)塑造的部分。本文的目標(biāo)是添加劑/消減過(guò)程中提出了規(guī)劃和執(zhí)行框架，勾勒出在開發(fā)這樣的環(huán)境中所涉及的問(wèn)題，這個(gè)方向快速原型在斯坦福大學(xué)實(shí)驗(yàn)室所取得的進(jìn)展的報(bào)告。 執(zhí)行系統(tǒng)讀取幾個(gè)備用進(jìn)程計(jì)劃（可能為許多不同的部分），并確定后續(xù)的操作和機(jī)器的基礎(chǔ)上上線的車間作業(yè)配置。 CAD系統(tǒng)的進(jìn)一步發(fā)展能夠代表多材料部件和梯度材料部件是一個(gè)活躍的研究領(lǐng)域，將有重大影響這些流程[Kumar和1997年杜塔。 工業(yè)SDM店需要確定調(diào)度部分和操作，樓層布局，分配工作機(jī)器等。 內(nèi)容包含機(jī)器可理解的駕駛指定機(jī)器的代碼執(zhí)行所需的操作哪里序列指定所有可能的操作是有效的訂單，制造輸入部分。與每個(gè)單步的幾何形狀相關(guān)聯(lián)的操作可以包括不同類型的材料或機(jī)器，使用數(shù)控機(jī)床，或放電加工的加工操作的沉積。一種方法，表面法線映射到單位球上，并確定在最小數(shù)目的底切非倒勾轉(zhuǎn)換的結(jié)果的方向，皮尼利亞等人描述的[拉賈戈帕蘭。 這些功能增加加工困難，并且可能需要更昂貴的和費(fèi)時(shí)的過(guò)程，例如，放電加工（EDM）??體積，它們的共享表面不需要被精確地定義，除非它們由不同的材料組成。材料通常沉積在連續(xù)的二維層，直到完全建立一個(gè)單步的幾何形狀。在加/減法流程，自動(dòng)生成加工路徑由于涉及的加工操作怒江 MBER 是至關(guān)重要的 。部分建設(shè)和流程描述語(yǔ)言（PDL）部件內(nèi)置一系列操作。 已經(jīng)設(shè)計(jì)過(guò)程描述語(yǔ)言，以適應(yīng)這一要求。 店控制systemKeeps，軌道建設(shè)各部分的狀態(tài)。 這種類型的系統(tǒng)支持多重代理合作，以控制生產(chǎn)[馬圖拉納和1995年諾里，拉莫斯1996年，1997年龔]。斯坦福大學(xué)快速成型實(shí)驗(yàn)室正在開發(fā)的當(dāng)前進(jìn)程的策劃是基于UNI圖形系統(tǒng)和它的API的。該軟件具有三個(gè)主要部分：機(jī)器控制的硬件接口，流程描述語(yǔ)言的解釋器/調(diào)度負(fù)責(zé)，對(duì)網(wǎng)絡(luò)接口，將允許通過(guò)網(wǎng)絡(luò)遠(yuǎn)程作業(yè)提交，以方便設(shè)計(jì)和制造方案描述在[拉賈戈帕蘭，皮尼利亞等。編纂過(guò)程描述語(yǔ)言編碼序列來(lái)自建設(shè)樹及其相關(guān)的制造業(yè)信息......編碼的過(guò)程描述所有可能的建筑被解釋執(zhí)行系統(tǒng)控制和監(jiān)視所有的部分建設(shè)活動(dòng)的整體計(jì)劃。 沉積和加工代碼，然后生成的每個(gè)單步的幾何形狀。1998]。 整體店鋪控制在一個(gè)模擬一套這樣的機(jī)器將被測(cè)試。 Gowan的1996點(diǎn)的信息系統(tǒng)架構(gòu)，采用分布式計(jì)算系統(tǒng)[懷特塞德，Pancerella等人。車間調(diào)度活動(dòng)和制造機(jī)器的操作實(shí)現(xiàn)店鋪信息系統(tǒng)實(shí)施上線訪問(wèn)的狀態(tài)和控制的機(jī)器。 一個(gè)這樣的例子，在圖2中單步3和7的幾何形狀不要求任何特殊訂貨它們之間建立一個(gè)正確的部分。 可能需要其他輔助業(yè)務(wù)作為主要操作之間的橋梁。 這是因?yàn)椋呀ǔ闪艘粋€(gè)單步的幾何形狀的凹特征的任何支持在早期階段和部分加工的限制，可以進(jìn)一步分解。它們的優(yōu)先級(jí)圖，可以生成一組不同的建筑計(jì)劃。 模型，然后分解和支撐結(jié)構(gòu)產(chǎn)生一些擠壓操作的幫助。為了便于加工任務(wù)的部分，優(yōu)選的是具有盡可能多的盡可能的平坦表面或垂直表面相對(duì)于建筑物方向。 等分解的幾何形狀（一組單步的幾何形狀）的特性，以前生成的所有支持它的側(cè)凹特征，無(wú)干擾發(fā)生在建設(shè)方向相對(duì)于從頂部沉積或成形過(guò)程。 晶圓，路線穿越可變數(shù)量的機(jī)器，取決于它的工藝方案，是非常循環(huán)（光刻蝕刻植入物）。SDM和其他添加劑/消減過(guò)程呈現(xiàn)出復(fù)雜性大幅增加，相比純添加劑的關(guān)于執(zhí)行環(huán)境。在下面的章節(jié)中，我們將只解決相關(guān)問(wèn)題的處理添加劑的規(guī)劃和執(zhí)行/消減SFF過(guò)程的任何制造系統(tǒng)的一個(gè)現(xiàn)實(shí)的計(jì)劃和執(zhí)行系統(tǒng)的第一個(gè)要求是能夠連接現(xiàn)有的CAD系統(tǒng)。 例如，可制造性分析儀，檢查公差要求設(shè)計(jì)和驗(yàn)證他們的設(shè)備和加工能力。所有這些缺點(diǎn)改進(jìn)是添加劑/消減過(guò)程需要一個(gè)更復(fù)雜的過(guò)程規(guī)劃和部分執(zhí)行控制。然而，創(chuàng)建一個(gè)模型或原型設(shè)計(jì)的過(guò)程中維持勞動(dòng)和技能密集型的過(guò)程，直到組統(tǒng)稱為固體自由形式加工成為可行。 Gowan 1996] point to information system architectures using a distributed puting system [Whiteside, Pancerella et al. 。step geometries can be constructed. From this precedence graph, one can identify in what order the singlestep models should be built. With the precedence graph, a set of alternative building plans can be generated. Each plan represents a possible building sequence on the deposed geometry and can be chose optimally depending upon machine availability or other criteria such as minimum building time, or best possible surface finishing, etc. These building alternatives are passed to job shops for runtime jobshop scheduling. Material is usually deposited in consecutive 2D layers until a singlestep geometry is pletely built. The advantages of additive/subtractive processes are that deposition may not need to be netshaped since material removal processes are involved. This helps reduce stress concentration and warpage problems and improve deposition path optimality that could reduce voids during deposition. An algorithm that describes a method of relaxing 2Dlayer