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課程設(shè)計說明書 題 目 皮帶輪落料拉深復(fù)合模設(shè)計 學(xué) 院 機械工程學(xué)院 專 業(yè) 材料成型及控制工程 學(xué) 號 姓 名 指導(dǎo)教師 完成日期 2008 年 2 月 29 日 目 錄 1 目 錄 1 第 一 章 零 件 的 工 藝 性 分 析 2 第 二 章 毛 坯 尺 寸 展 開 計 算 3 第 三 章 拉 深 工 序 次 數(shù) 及 拉 深 系 數(shù) 確 定 5 第 四 章 沖裁力與拉深力的計算 11 第 五 章 凸 凹 模 的 設(shè) 計 7 1 落料凸 凹模尺寸計算 7 2 拉深凸 凹模尺寸計算 8 3 粗糙度的確定 9 第 六 章 模 具 基 本 結(jié) 構(gòu) 的 確 定 13 第 七 章 模具主要零件的強度校核 15 第 八 章 沖 壓 設(shè) 備 的 選 擇 16 1 初 選 設(shè) 備 16 2 設(shè) 備 的 校 核 18 主 要 參 考 文 獻 附 錄 第一章 零件的工藝性分析 2 1 零件的形狀 尺寸及一般要求 該零件為厚度 2mm 大筒直徑為 86 8mm 小筒直徑為 47mm 的皮帶輪 零件材料 T8 尺寸精度按圖紙要求 2 工藝方案的分析及確定 工件由落料 拉深 反拉深三道工序成型 工件形狀較簡單 根據(jù)計算可知 拉深工序需要進行多次拉深才能完成 如果完 全采用連續(xù)模 則模具結(jié)構(gòu)比較復(fù)雜會增加沖壓件的生產(chǎn)成本 所 以可先采用復(fù)合模進行落料和第一步拉深 然后采用連續(xù)模直至拉 深完成 再采用單工序模進行反拉深 本次主要設(shè)計其第一道工序 即落料和第一步拉深 第二章 毛坯尺寸展開計算 3 旋轉(zhuǎn)體零件采用圓形毛坯 在不變薄拉深中 材料厚度雖有變 化 但其平均值與毛坯原始厚度十分接近 因此 其直徑按面積相 等的原則計算 即毛坯面積與拉深件面積 加上修邊余量 相等 1 確定修邊余量 在拉深的過程中 常因材料機械性能的方向性 模具間隙不均 板厚變化 摩擦阻力不等及定位不準等影響 而使拉深件口部周邊 不齊 必須進行修邊 故在計算毛坯尺寸時應(yīng)按加上修邊余量后的 零件尺寸進行展開計算 修邊余量的數(shù)值可查文獻 實用模具技術(shù)手冊 表 5 7 由于工件凸緣的相對直徑 d 凸 d 1 1013 查表可得修邊余量 3 5mm 2 毛坯尺寸計算 根據(jù)工件的形狀 可將其分成 F1 F8 這幾個部分 則可計算出 各部分的展開面積如下 4 F1 4 2 4 t 2 90 8 t 4 56 4 t 2 4 2 5 88 8 4 56 5 222 28 5 F2 d t h r1 r2 t 90 8 2 34 4 2 2 2308 8 F3 4 2 2 t 2 90 8 t 2 2 t 8 2 t 2 4 2 3 82 8 72 124 2 18 F4 4 90 8 2t 2 2 4 47 2t 2 2 4 82 8 4 55 957 71 F5 4 2 2 t 2 47 t 4 56 2 t 2 4 2 3 49 4 56 3 73 5 10 26 F6 20 2t 2 2 47 t 588 F7 4 2 2 t 2 47 2 2 8 2 t 2 4 2 3 43 8 3 64 5 18 F8 4 47 2 2 462 25 5 得 4D 222 28 5 2308 8 124 2 18 957 71 73 5 10 26 588 64 5 18 462 25 D 1936 8 17566 08 23647 632 所以經(jīng)計算求得毛坯直徑 D 154mm 3 確定是否使用壓邊圈 由于 D d 22t 則要使用壓邊圈 壓邊力的計算 因為 k D d 154 47 4 3 Fmax dt k 1 b 3 14 51 2 2 329 210 7 kN 所以 F 0 1 1 18k k 1 k Fmax 0 1 1 18 3 3 1 3 210 7 0 1 0 65 9 210 7 123 4kN 第三章 拉深工序次數(shù)及拉深系數(shù)確定 在制定拉深件的工藝過程和設(shè)計拉深模具時 必須預(yù)先確定是 否可以一道工序完成 或者是經(jīng)過幾道工序才能制成 在確定拉深 工序次數(shù)時 必須做到使毛坯內(nèi)部的應(yīng)力既不超過材料的強度極限 6 而且還能充分利用材料的塑性 也就是說每一次拉深工序 應(yīng)在毛 坯側(cè)壁強度允許的條件下 采用最大可能的變形程度 制訂拉深工藝時 為了減少拉深次數(shù) 希望采用小的拉深系數(shù) 大 的拉伸比 有力學(xué)分析可知 拉深系數(shù)過小 將會在危險斷面產(chǎn)生 破裂 因此 要保證拉深順利進行 每次拉深系數(shù)應(yīng)大于極限拉深 系數(shù) 該零件的拉深系數(shù) 即拉深后圓筒件直徑與拉深前毛坯直徑的 比值 為 m d D 47 4 154 0 33 有凸緣的圓筒件在拉深時還要考慮拉深的相對高度是否大于極 限相對高度 計算可得拉深的相對高度為 h d 20 47 4 0 392 極限拉伸系數(shù)與板料成形性能 毛坯相對厚度 凸凹模間隙及 其圓角半徑有關(guān) 通過計算可得 4dF 756 25 73 5 10 26 588 64 5 18 462 25 484 2 4391 52 dF 143 6 所以 法蘭相對直徑 dF d 143 6 47 2 2 93 毛坯的相對厚度 t D 100 2 154 100 1 3 依文獻 沖壓工藝學(xué) 查表 4 10 查得零件的極限拉深系數(shù) m 0 32 7 依文獻 實用模具技術(shù)手冊 查表 5 16 查得第一次拉深的最 大相對高度 h d 0 18 可知拉深系數(shù)大于極限拉深系數(shù) 拉深的相對高度大于極限相 對高度 所以不能一次拉深成形 由于本設(shè)計只進行第一次拉深的設(shè)計 所以對以后的多次拉深 不進行計算 第四章 沖裁力與拉深力的計算 1 沖裁力的計算 計算沖裁力的目的是為了合理地選用壓床和設(shè)計模具 壓床的 噸位必須大于所計算的沖裁力 以適應(yīng)沖裁的要求 平刃模具沖裁時 其沖裁力 F0可按下式計算 F0 Lt 式中 t 材 料 厚 度 t 為 mm 材 料 抗 剪 強 度 為 MPa L 沖 裁 周 長 L 為 mm 考 慮 到 模 具 刃 口 的 磨 損 凸 凹 模 間 隙 的 波 動 材 料 機 械 性 能 的 變 化 材 料 厚 度 偏 差 等 因 素 實 際 所 需 沖 裁 力 還 須 增 加 30 即 F 1 3F0 1 3Lt 8 所以沖裁力 F 1 3 2 154 2 2 260 326 89 kN 因為模具采用剛性卸料裝置 所以不用計算卸料力 而 F 頂件力 K2F 0 06 326 89 19 62 kN 依文獻 沖壓工藝學(xué) 查表 2 10 得 K2 0 06 所以總沖裁力為 F0 326 89 19 62 346 51 kN 2 拉深力的計算 在確定拉伸件所需的壓力機噸位時 必須先求的拉深力 在拉 深帶法蘭的圓筒件的生產(chǎn)中常用如下經(jīng)驗公式計算 F d1t bK 式中 t 料厚 d1 第一次拉深半成品圓筒直徑 b 抗拉強度 由于零件材料為 T8 鋼 查得其抗拉強度 為 329MPa K 系數(shù) 依文獻 沖壓工藝學(xué) 查表 4 11 查得 K 1 由上求得拉深力 F 103 3 kN 第五章 凸 凹模設(shè)計 9 1 落料凸 凹模尺寸計算 因為落料形狀為圓形 形狀簡單 所以采用凸 凹模分開加工 的方法 查文獻 沖壓工藝學(xué) 表 2 3 可知 沖裁模的雙面間隙為 Z min 0 12mm Zmax 0 16mm 則凸模和凹模的制造公差分別為 p 0 4 Zmax Zmin 0 4 0 16 0 12 0 016 d 0 6 Zmax Zmin 0 6 0 16 0 12 0 024 設(shè)工件尺寸為 D 落料時首先確定凹模尺寸 使凹模公稱尺 寸接近或等于工件輪廓的最小極限尺寸 再減小凸模尺寸以保證最 小合理間隙 Zmin 則凸 凹模的尺寸計算公式如下 Dd D x d DP Dd Zmin p D x Z min p 式中 D d D P 落料凹 凸模尺寸 D d 與 D P 為 mm 工件制造公差 為 mm Zmin 最小合理間隙 雙面 Zmin 為 mm p d 凸 凹模的制造公差 p d 為 mm x 磨損量 其中系數(shù) x 是為了使沖裁件的實際尺寸 盡量接近沖裁件公差帶的中間尺寸 查文獻 沖壓工藝學(xué) 表 2 7 可知 x 0 75 2 拉深凸 凹模尺寸計算 10 一 凹 模 圓 角 半 徑 rd rd 與 毛 坯 厚 度 零 件 的 形 狀 尺 寸 和 拉 深 方 法 有 關(guān) 因 為 D dd 凹 模 內(nèi) 徑 30 時 應(yīng) 取 較 大 的 rd 值 查 文 獻 沖 壓 工 藝 學(xué) 表 4 6 可 得 rd 9mm 二 凸 模 圓 角 半 徑 rp 一 般 可 取 rp rd 最 后 一 道 拉 深 時 rp 等 于 零 件 的 圓 角 半 徑 所 以 取 rp rd 9mm 三 凸 凹 模 間 隙 c 決 定 凸 凹 模 間 隙 時 不 僅 要 考 慮 材 質(zhì) 和 板 厚 還 要 考 慮 工 件 的 尺 寸 精 度 和 表 面 質(zhì) 量 要 求 由 于 該 拉 深 要 使 用 壓 邊 圈 則 C tmax kt 取 C 2mm 式 中 tmax 材 料 最 大 厚 度 k 間 隙 系 數(shù) 由 于 零 件 的 尺 寸 標 注 在 內(nèi) 徑 上 則 依 凸 模 為 準 間 隙 取 在 凹 模 上 即 增 大 凹 模 尺 寸 得 到 間 隙 四 凸 凹 模 尺 寸 及 制 造 公 差 最 后 一 道 拉 深 模 的 尺 寸 公 差 決 定 了 零 件 的 尺 寸 精 度 故 其 尺 寸 公 差 應(yīng) 按 零 件 要 求 來 確 定 對 于 多 次 拉 深 的 第 一 次 拉 深 和 中 間 工 序 的 毛 坯 尺 寸 公 差 沒 11 有 必 要 限 制 此 時 可 取 模 具 尺 寸 等 于 毛 坯 過 渡 尺 寸 若 取 凸 模 為 基 準 則 凸模尺寸 D P D p 凹 模 尺 寸 Dd D 2c d 根據(jù)拉深系數(shù) m 0 32 即 d 154 0 32 d 50 則 D 50 2t 46 凸 凹模的制造公差依文獻 沖壓工藝學(xué) 查表 4 7 依工件 的厚度和拉深直徑 查得 d 0 08 p 0 05 則 D P 46 0 05 Dd 50 0 08 3 粗糙度的確定 凸凹模的刃口部位要求較高 粗糙度選用 0 4 凸模及凹模 鑲塊用于固定的部位選用 0 8 對于固定板上的孔 由于加工較困難 可選用 1 6 其它不太重要的部位選用 6 3 第六章 模具基本結(jié)構(gòu)的確定 模具的基本結(jié)構(gòu)和組成如下所示 12 1 凸 凹模的結(jié)構(gòu)形式 一 落料凸模與拉深凹模 采用凸緣形式 用螺栓與上模板緊固 模具結(jié)構(gòu)如下圖所示 二 落料凹模 模具結(jié)構(gòu)如下圖所示 13 三 拉深凸模 采用嵌入式結(jié)構(gòu) 用螺釘與下模板緊固 模具結(jié)構(gòu)如下圖所示 2 模具其他部分的作用與選材如下 上模座 1 上模座的作用是通過模柄與壓力機相連接 將模具的上模部分 安裝在壓力機上 材料選用 HT200 因為上模座在模具工作中只承 14 受沖擊力 要求材料具有較好的強度和韌性 上模座尺寸選用 315mm 200mm 45mm 上模墊板 2 上模墊板在模具工作過程中 承受卸料組件 沖頭傳遞過來的 較大的沖擊載荷 因此要求材料有較好的強度 硬度和一定的韌性 選用 45 調(diào)質(zhì)到 HRC38 43 卸料板 3 本模具選用固定卸料板 用螺栓和銷釘固定在下模上 能承受 的卸料力較大 常用于厚板沖壓件的卸料 厚度為 6mm 材料選用 45 鋼 調(diào)質(zhì) HRC38 43 定位板 4 定位板在過程中起到保證單個毛坯在拉深過程中有正確位置的 作用 以保證拉深出合格的制件 通過螺釘與凹模固定板連接 以毛 坯外形進行定位 厚度為 5mm 材料選用 45 鋼 調(diào)質(zhì) HRC38 43 拉深凸模固定板 5 該固定板在模具中不僅起穩(wěn)定拉深凸模的作用 還通過其與下 模板之間的彈簧的作用起到壓邊圈的作用 在工作過程中要承受來 自落料凸模的沖擊 因此要求材料有較好的強度 硬度和一定的韌 性 選用 45 調(diào)質(zhì)到 HRC38 43 下模固定板 6 承受很大的沖擊載荷 需要有較好的韌性和強度 選用 45 鋼 下模座 7 15 其作用與上模座相似 選用 HT200 尺寸選用 315mm 200mm 55mm 2 模架 選定模具的基本形式后 開始選擇模架 依凹模尺寸及壓力機 工作臺尺寸選取 根據(jù)文獻 實用模具技術(shù)手冊 選用后側(cè)導(dǎo)柱模 架 選用 HT200 其各尺寸參數(shù)如下 凹模周界 D 200 mm B 200mm L 315mm 閉合高度 190 230mm 導(dǎo)套 32mm 160mm 導(dǎo)柱 32mm 43mm 110mm 其結(jié)構(gòu)形式如下圖 本模具采用人工送料 16 第七章 模具主要零件的強度校核 1 壓力中心的確定 為了保證壓力機和模具正常的工作 必須使沖模的壓力中心與 壓力機滑塊中心線相重合 否則在沖壓時會使沖模與壓力機滑塊歪 斜 引起凸 凹模間隙不均和導(dǎo)向零件加速磨損 造成刃口和其它 零件的損壞 甚至還會引起壓力機導(dǎo)軌磨損 影響壓力機精度 本 制件為圓形 壓力中心在圓心 2 模具主要零件強度設(shè)計 凸 凹模 1 凸模長度確定以后 一般不作強度計算 且該凸模直徑較大 不會造成縱向失穩(wěn)或折彎 故可不進行校核 同理 凹模外形尺寸確定以后 可以保證凹模具有足夠的強度 和剛度 也不做強度校核 墊板 2 墊板的作用是為了平均分布模板所受到的壓力 可根據(jù)凸模傳 給的壓力來決定墊板是否合格 17 第八章 沖壓設(shè)備的選擇 沖 壓 設(shè) 備 的 選 擇 直 接 關(guān) 系 到 設(shè) 備 的 合 理 使 用 安 全 產(chǎn) 品 質(zhì) 量 模 具 壽 命 生 產(chǎn) 效 率 和 成 本 等 一 系 列 問 題 1 初 選 設(shè) 備 沖壓生產(chǎn)中主要應(yīng)用的是曲柄壓力機和液壓機 由于本零件的 成型屬于落料淺拉深 且根據(jù)其幾何尺寸和精度要求 選用具有 C 形床身的開式曲柄壓力機 雖然開式壓力機的剛度差 并且由于床 身變形而破壞了沖模的間隙分布 降低了沖模的壽命和制件的質(zhì)量 但是 它卻具有操作空間三面敞開 操作方便 容易安裝機械化的 附屬設(shè)備和成本低廉等優(yōu)點 在壓力機的類型選定以后 應(yīng)進一步根據(jù)變形力的大小 沖壓 件的尺寸和模具尺寸來確定設(shè)備的規(guī)格 由于沖裁工序與拉深工序不是同時進行 所以只需考慮兩工序 中所需壓力較大的工序 沖裁力為 F 346 51 kN 依沖壓力的計算圖與沖壓設(shè)備需要負 荷圖對比 故可選用公稱壓力為 450 kN 的壓力機 根據(jù)國標 JB T 9965 1999 初選壓力機的型號為 J21 45 依文獻 沖壓模具簡明設(shè)計手冊 表 13 10 可查得該壓力機個 技術(shù)參數(shù)如下 標稱壓力 kN 450 標稱行程 mm 3 2 18 滑塊行程 mm 120 行程次數(shù) 次 min 1 80 最大閉合高度 mm 270 封閉高度調(diào)節(jié) mm 60 滑塊中心線到機身距離 mm 225 工作臺尺寸 左右 mm 810 前后 mm 440 工作臺孔尺寸 mm 150 模柄孔尺寸 直徑 mm 50 深度 mm 60 電動機功率 kW 5 5 2 設(shè)備校核 裝模高度校核 1 為使模具正常工作 模具閉合高度必須與壓力機閉合高度相適 應(yīng) 應(yīng)介于壓力機最大和最小閉合高度之間 一般按如下關(guān)系確定 h 最大 5mm h 模 h 最小 10mm 所設(shè)計模具的閉合高度為 220mm 而壓力機的閉合高度為 210mm 270mm 在可調(diào)范圍之內(nèi) 滑塊行程校核 2 在拉深中為了便于安放毛坯和取出工件 其行程一般大于拉深件 高度的 2 5 倍 工件高度為 9mm 而壓力機行程為 60mm 故該壓力機 19 行程符合規(guī)定 模具安裝空間尺寸校核 3 包括工作臺面的大小和模柄孔尺寸 經(jīng)校核比較該模具可在壓 力機工作上正確安裝和定位 且臺面上的漏料孔與所選工藝相適應(yīng) 主 要 參 考 文 獻 主 要 參 考 文 獻 1 王 孝 培 沖 壓 手 冊 修 訂 本 機 械 工 業(yè) 出 版 社 1988 2 薛 啟 翔 冷 沖 壓 實 用 技 術(shù) 北 京 機 械 工 業(yè) 出 版 社 2006 3 鄭 家 賢 沖 壓 工 藝 與 模 具 設(shè) 計 實 用 技 術(shù) 北 京 機 械 工 業(yè) 出 版 社 2005 4 郝 濱 海 實 用 模 具 技 術(shù) 手 冊 北 京 化 學(xué) 工 業(yè) 出 版 社 2004 5 周 良 德 朱 泗 芳 等 現(xiàn) 代 工 程 圖 學(xué) 湖 南 湖 南 科 學(xué) 技 術(shù) 出 版 社 2000 6 肖 景 容 姜 奎 華 沖 壓 工 藝 學(xué) 北 京 機 械 工 業(yè) 出 版 社 2004 7 陳 錫 棟 周 小 玉 實 用 模 具 技 術(shù) 手 冊 北 京 機 械 工 業(yè) 出 版 社 2005 8 模 具 實 用 技 術(shù) 叢 書 編 委 會 沖 模 設(shè) 計 應(yīng) 用 實 例 北 京 機 械 工 業(yè) 出 版 社 2000 20 9 高 為 國 模 具 材 料 北 京 機 械 工 業(yè) 出 版 社 2005 10 王 衛(wèi) 衛(wèi) 材 料 成 形 設(shè) 備 北 京 機 械 工 業(yè) 出 版 社 2005 11 俞 漢 清 陳 金 德 金 屬 塑 性 成 形 原 理 北 京 機 械 工 業(yè) 出 版 社 2003 12 廖 念 釗 莫 雨 松 李 碩 根 楊 興 駿 等 互 換 性 與 技 術(shù) 測 量 北 京 中 國 計 量 出 版 社 2003 13 楊 可 楨 程 光 蘊 機 械 設(shè) 計 基 礎(chǔ) 第 四 版 北 京 高 等 教 育 出 版 社 1999 大連交通大學(xué) 2017 屆本科生畢業(yè)設(shè)計外文翻譯 1 knowledge based blackboard framework for stamping process planning in progressive die design S B Tor G A Britton W Y Zhang Springer Verlag London Limited 2004 Abstract It is widely accepted that stamping process planning for the strip layout is a key task in progressive die design How ever stamping process planning is more of an art rather than a science This is in spite of recent advances in the field of artificial intelligence which have achieved a lot of success in incorporating built in intelligence and applying diverse know ledge to solving this kind of problem The main difficulty is that existing knowledge based expert systems for stamping process planning lack a proper architecture for organizing heterogeneous knowledge sources KSs in a cooperative decision making en vironment This paper presents a knowledge based blackboard framework for stamping process planning The proposed ap proach speeds up the progressive die design process by automat ing the strip layout design An example is included to show the effectiveness of the proposed approach Keywords Knowledge based Object oriented Progressive die design Stamping process planning 1 Introduction Progressive dies for producing sheet metal parts in mass pro duction have been widely applied in various industries such as aerospace electronics machine tools automobiles and re frigeration These dies can perform piercing notching cut off blanking lancing bending shaving drawing embossing coin ing trimming and other miscellaneous forming operations at a single setup Hence a progressive die is generally very com plex Stamping process planning and die structure design are difficult and demanding tasks Stamping process planning starts with an unfolding of a model of stamped metal part to produce a flat pattern followed by nesting the pattern to produce a blank layout Next stamping operations are planned and operations are assigned to die sta tions The resulting plan is typically represented as a strip layout which guides the subsequent die structure design The produc tivity accuracy cost and quality of a progressive die mainly depends on the strip layout and hence a stamping process How ever stamping process planning still remains more of an art rather than a science Historically this activity is mainly car ried out manually based on designers trial and error experience skill and knowledge Recent advances in the field of artificial intelligence AI have given rise to the possibility to construct AI based systems that incorporate built in intelligence and apply diverse knowledge to 大連交通大學(xué) 2017 屆本科生畢業(yè)設(shè)計外文翻譯 2 solving progressive die design problems including strip layout design automation The diverse knowledge sources KSs re lated to stamping process planning include unfolding knowledge to produce a flat pattern nesting knowledge to produce a blank layout mapping knowledge to transform stamping features into stamping operations and staging knowledge to sequence the stamping operations A discussion of some knowledge based pro gressive die design work related to our study can be found in Sect 2 However the existing work is based on the conventional architecture of knowledge based expert systems which are in capable of managing heterogeneous KSs effectively This limits both their practicability and scalability To address the above issue it is necessary to provide a coop erative problem solving strategy that can foster communication between diverse KSs and accommodate different knowledge representation schemes within an integrated framework Hence a knowledge based blackboard framework consisting of a black board control system and a few independently executing KSs have been developed This framework provides a cooperative de cision making environment and facilitates a hybrid knowledge representation scheme including procedures production rules and object oriented representations A prototype system has been implemented using the object oriented expert system shell CLIPS C Language Integrated Pro duction System 1 which is interfaced with a parametric and feature based CAD system Solid Edge through C An ex ample is provided to demonstrate our approach and to show its effectiveness in stamping process planning 2 Related work Research in the computer aided stamping process planning has been widely reported since the 1970s The advantages of auto mated process planning are productivity improvements cost re ductions and design automation From the mid 1970s to mid 1980s the first generation of CAD CAM systems for progressive die design were de veloped 2 5 though few of them are based on AI techniques These early systems are characterized by basic computer graph ics facilities standardization of die components and standard ization of design procedures They reduced design and drafting lead time However as these systems represent design know how in the form of conventional procedural programming languages only generation of the die part list and drafting of the assembly and part drawings are executed using computers The designer still needs to decide most of the important decisions interactively including strip and die layouts Since the late 1980s significant efforts have been made by worldwide researchers to integrate a wide variety of AI and traditional CAD approaches to develop dedicated progressive die design automation systems including strip layout design automation Knowledge based approach is a popular AI technique that has been used in intelligent stamping process planning and die design system For example researchers at the University of Massachusetts USA have described a knowledge based sys tem for design of progressive 大連交通大學(xué) 2017 屆本科生畢業(yè)設(shè)計外文翻譯 3 stamping dies for a simple hinge part 6 The system generates the flat pattern geometry and de velops a strip layout automatically Researchers at the National University of Singapore have been developing an intelligent pro gressive die IPD design system since the late 1980s They used feature modeling and rule based approach to realize automatic punch shape selection strip layout development and 3 D die configuration 7 8 Based on a feature relationship tree that de scribes the stamped metal part and its topological information model based reasoning and spatial reasoning techniques have been employed to reason out certain stamping processes and guide the overall planning process to develop the strip layout automatically Researchers at the Indian Institute of Technology have developed a computer aided die design system CADDS for sheet metal blanks 9 based on heuristic rule based reason ing and parametric programming techniques The greatest advan tage achieved by the system is the rapid generation of the most efficient strip layouts Researchers at the University of Liverpool have worked on design automation for progressive piercing and blanking dies 10 11 Their work is based on applying a coding technique to characterize the stamped part geometric features which is subsequently used to generate the type and layout of the die punches and then develop the strip layout automatically Researchers at Huazhong University of Science and Technol ogy China have developed an intelligent progressive die design system HPRODIE 12 With feature mapping rule based rea soning and case based reasoning techniques most of the design processes including strip layout design can be carried out auto matically Researchers at Pusan National University Korea have developed a compact computer aided process planning CAPP system for progressive die design 13 Based on production rules the work is capable of carrying out an intelligent stamp ing process planning work with automatic development of blank layout strip layout and die layout Though knowledge based systems have achieved a lot of suc cess in stamping process planning most of the intelligent pro gressive die design automation prototypes reviewed above are rather restricted to specific application domains or still need considerable interactive input from experienced designers to de velop strip layouts This is because they still inherit the disadvan tages of the conventional architecture of knowledge based expert systems which are incapable of managing heterogeneous KSs effectively Researchers at the National Taiwan Institute of Technology have adopted various AI techniques including fuzzy reasoning pattern recognition rule based reasoning back propagation neu ral network genetic algorithms and Petri nets for the stamping process planning and design of progressive shearing cut and bending dies 14 16 However their work lacks an explicit and consistent model to integrate these AI techniques into a compre hensive design environment In this paper another popular AI technique blackboard ar chitecture is adopted to develop a blackboard based stamping process planning system In the last two decades blackboard ar chitecture has been successfully used in a wide variety of areas such as speech recognition 大連交通大學(xué) 2017 屆本科生畢業(yè)設(shè)計外文翻譯 4 signal processing engineering de sign and process planning Thompson and Lu 17 used a black board architecture to provide a cooperative decision making en vironment that is suitable for concurrent product and process design Srihari et al 18 developed a real time CAPP system for printed circuit board PCB assembly by integrating multiple KSs including planning expert and dynamic information pro cessing modules in the blackboard architecture Chen et al 19 developed a concurrent product design evaluation system using a blackboard architecture to classify knowledge into diverse KSs suitable for qualitative and quantitative evaluation respectively In the past few years blackboard architecture has proven to be suitable for tooling design such as fixture design 20 and in jection moulding design 21 though this kind of application is still in its infancy stage Roy and Liao 20 report the preliminary work that investigates the suitability of using a blackboard archi tecture as a K1 problem solving model for fixture design It de scribes the creation of various functional KSs for fixture design and their organization in a cooperative problem solving environ ment Kwong et al 21 proposes a blackboard based system for concurrent process design of injection moulding which facili tates the simultaneous considerations of moulding part design tool design machine selection production scheduling and cost as early as possible in the conceptual design stage However we have not found in the literature any attempt to apply the blackboard architecture to stamping process planning for sheet metal parts It has been mentioned in our earlier work 22 that a blackboard architecture is well suited for constructive prob lem solving like process planning of stamping operations where the problem space is large and knowledge from many different sources must be integrated to achieve a solution This topic is now to be extensively elaborated in the present paper 3 Blackboard framework for stamping process planning Cooperative decision making for knowledge based stamping process planning involves a variety of KSs such as unfolding knowledge to produce flat pattern nesting knowledge to produce blank layout mapping knowledge to transform stamping features into stamping operations and staging knowledge to sequence the stamping operations These KSs may be expressed in different representation schemes such as procedures rules and objects This justifies the use of a blackboard framework that can man age heterogeneous KSs effectively The KSs interact through the blackboard to develop a solution incrementally The proposed blackboard framework consists of three major components the blackboard data structure KSs and a control module Fig 1 and was developed using object oriented expert system shell CLIPS The different components of the blackboard framework are described as follows 大連交通大學(xué) 2017 屆本科生畢業(yè)設(shè)計外文翻譯 5 3 1 Object oriented blackboard data structure The blackboard is a globally accessible database which con tains the data and partial solutions and is shared by a number of independent KSs The KSs contribute their partial solutions to the blackboard which lead to a final solution incrementally The blackboard is structured as a hierarchy of solution parti tion levels which represent different aspects or stages of the solution process Partial solutions are associated with each level and may be linked to information on other levels using algorith mic procedures or heuristic rules Each level contains planning objects that are used to represent the solution space in an object oriented manner This leads to the added advantage in knowledge system development because object oriented approach supports software modularity reusability and scalability Referring to Fig 1 the planning solution is partitioned into four different object levels stamping part stamping features stamping operations and stamping process plan each represent ing initial input or different partial solutions posted on the black board by the specialist KSs They are described as follows 3 1 1 Input data to the blackboard Input data to the blackboard mainly includes the part and press ob jects The generic declaration of a part object includes the basic attributes such as part type part dimensions weight surface treat ments blank thickness blank material annual production blank dimensions etc and points to its constituent stamping feature ob jects that will be elaborated later on The press object contains the attributes such as press type press tonnage bolster dimensions bed open dimensions shut height number of strokes etc 3 1 2 Object oriented feature modeling to stamped metal parts Since traditional geometric modeling techniques do not capture design intent e g design for manufacturing they are in gen eral unable to support sophisticated and intelligent reasoning 大連交通大學(xué) 2017 屆本科生畢業(yè)設(shè)計外文翻譯 6 capabilities e g knowledge based process planning Recently the concept of machining features has been introduced to cre ate a direct link between design and manufacturing 23 Feature modeling is a relatively new way of storing design and manu facturing information in CAD CAM CAPP systems Similarly stamping features of a stamped metal part can enable stamping process planning tasks to be performed directly from the geo metric model Stamping features are information carriers that are used to model a stamped part with a set of design and manu facturing information including geometric and non geometric at tributes Each of these stamping features can be manufactured with a specific stamping operation or a combination of stamping operations Using the hierarchical classification structure of general de sign features by Chen et al 24 a stamped metal part can be modeled with four categories of stamping features Primary features flat drawing etc Positive secondary features tab curl emboss hem bead flange etc Negative secondary features hole extrusion hole profile de form slot step etc andConnective secondary features bend blend etc In this work the object oriented feature representation is em ployed to encapsulate design and manufacturing information in a stamping feature object For example a hole feature object contains the basic attributes such as feature type feature ID pri mary feature ID position orientation depth diameter precision roughness etc and methods to calculate perimeter Besides representation of individual stamping features a comprehensive representation of feature relations guarantees that all the stamping features associated with stamping process planning are considered In addition the data on feature relations are useful for determining the sequence of stamping operations and sometimes the stamping operations themselves Four criti cal types of relations among stamping features is in is on adjacent to and precision associated are identified which have been elaborated in our previous work 25 and won t be repeated in this paper for conciseness For example a precision associated relation represents design constraints that arise when a stamping feature does not directly connect to but is associ ated with another stamping feature by a toleranced dimension The feature relation data is also included in the feature object for more complete feature modeling 3 1 3 Stamping operation objects mapped from stamping feature objects On the blackboard the stamping operation objects are in a lower level than the stamping feature objects and are used to define the manufacturing process from metal strip to the formed metal part Stamping features constitute a stamped part while stamp ing operations are selected as elements of a stamping process plan Essentially the stamping process planning task is to trans form a set of stamping features into a set of stamping opera tions and to describe the relations between these The generic declaration of a stamping operation object includes stamping op eration type geometric shapes geometric constraints precision roughness relationships with stamping features control param eters etc Typical stamping operation objects include piercing 大連交通大學(xué) 2017 屆本科生畢業(yè)設(shè)計外文翻譯 7 notching cut off blanking lancing shaving drawing emboss ing coining trimming and other miscellaneous forming opera tions A stamping feature may be manufactured with a specific stamping operation one to one mapping or a combination of stamping operations one to many mapping Several stamping features may also be manufactured with a single stamping oper ation many to one mapping 3 1 4 Graph based stamping process plan After the mapping from stamping features to a set of stamping operations the remaining process planning task is to assign each stamping operation to the relevant die station according to an op timal sequence of stamping operations Stamping operations are sequenced in a progressive manner by creating stamping opera tion relations and using them to form a stamping process plan This formal description of operation relations forms the founda tion of automatic strip layout design A graph based approach is used to arrange the stamping op eration objects in a stamping process plan The graph consists of a set of nodes that store information about the stamping opera tions and a set of arcs that store information about the operation relations Stamping operations are related to one another through two kinds of relationship cluster or precedence relations Cluster stamping operations are executed simultaneously and can be staged at the same die station Stamping operations in prece dence must be performed in sequence and so they are staged in adjacent die stations Cluster relation and precedence rela tion are represented by dashed ellipses and directed solid line respectively as shown in Fig 2 Note that stamping operations B and C work simultaneously and are staged at the same die station while stamping operation A precedes operation B and is staged in a die station immediately prior to the one for the operation B The strip layout can be generated by a computer automat ically using the graph based stamping process plan which is suited for computer implementation and leads to efficient formu lation and solution procedures 以沖壓工藝規(guī)劃知識進行的級進模設(shè)計 大連交通大學(xué) 2017 屆本科生畢業(yè)設(shè)計外文翻譯 8 摘 要 人們普遍認為沖壓工藝規(guī)劃的布局是級進模設(shè)計中的關(guān)鍵任務(wù) 有史以來 沖壓工藝 規(guī)劃是一門藝術(shù) 而不是一門科學(xué) 雖然人工智能在將內(nèi)置的智能和應(yīng)用多樣化的知識窗 臺解決這類問題已經(jīng)取得了很多最新進展 而現(xiàn)在主要的困難是 現(xiàn)有的基于知識的專家 系統(tǒng) 沖壓工藝規(guī)劃缺乏適當(dāng)?shù)募軜?gòu)組織異構(gòu)知識源 KSS 的合作決策 EN vironment 本文提出了沖壓工藝規(guī)劃知識型面板框架 建議 AP proach 通過自動售貨機 荷蘭國際 集團的帶狀布局設(shè)計 加快了級進模設(shè)計過程 關(guān)鍵詞 基于知識 面向?qū)ο?級進模具設(shè)計 沖壓工藝規(guī)劃 1 引言 級進模在大眾中生產(chǎn)鈑金件已被廣泛應(yīng)用于各種行業(yè) 如航空航天 電子 機床 汽 車 這些模具可在一次裝夾完成穿孔 開槽 切斷 落料 彎曲 刮 拉絲 浮雕 修剪 和其他雜項成形操作 因此 級進模通常是非常復(fù)雜的 因此沖壓工藝規(guī)劃和模具結(jié)構(gòu)設(shè) 計是困難的 苛刻的任務(wù) 沖壓工藝規(guī)劃開始 沖壓金屬部件的模型的展開 以產(chǎn)生一個平面的圖案 隨后通過 嵌套圖案 以產(chǎn)生一個空白的布局 下一步 計劃沖壓操作和操作分配到工步 由此產(chǎn)生 的計劃通常表示為一個帶狀布局 指導(dǎo)后續(xù)的模具結(jié)構(gòu)設(shè)計 在全局模具生產(chǎn)過程中 模 具的精度 成本 和一個級進模的質(zhì)量主要取決于帶布局 這使得有史以來 沖壓工藝設(shè) 計是一門藝術(shù) 而不是一門科學(xué) 從歷史上看 這項活動主要是汽車生產(chǎn)里衍生出來的 根據(jù)設(shè)計師的試錯經(jīng)驗 技能和知識來進行模具的設(shè)計 在人工智能 AI 領(lǐng)域的最新進展引起的可能性 以構(gòu)建包含內(nèi)置的智能 AI 為基礎(chǔ) 的系統(tǒng)和多樣化的知識應(yīng)用于解決級進模的設(shè)計問題 其中包括條帶布局設(shè)計自動化 多 樣化的知識源 KSS 到?jīng)_壓工藝規(guī)劃 包括展開知識 以產(chǎn)生一個平面的圖案 排料的 知識 以產(chǎn)生一個空白