鋁型材擠壓機液壓部分的設計【鋁型材擠壓機液壓系統(tǒng)的設計及研究】

鋁型材擠壓機液壓部分的設計【鋁型材擠壓機液壓系統(tǒng)的設計及研究】,鋁型材擠壓機液壓系統(tǒng)的設計及研究,鋁型材擠壓機液壓部分的設計【鋁型材擠壓機液壓系統(tǒng)的設計及研究】,鋁型材,擠壓,液壓,部分,部份,設計,系統(tǒng),研究,鉆研 附錄Ⅰ 外文文獻原文 A hydraulic high-speed tryout press for the simulation of mechanical forming processes Abstract The tryout of dies plays an important part in the manufacturing of dies and in the production process in general. Despite CAD simulations, the tryout of new dies still requires a lot of time and work. Very often the time-consuming tests are conducted on expensive production lines because the presses used in the die shop, due to their different characteristics, are not suitable to reproduce the exact characteristics of the production presses. The same conditions apply after die change or after repairs of dies. Much time is consumed before the smooth production of perfect parts is possible and this, in turn, affects the productivity and the efficiency of the production equipment. As the number of die change-over operations increases together with the reduction of lot sizes caused by the increase of car model variety, shortening the time of adjustment work offers a large potential of cost saving. This is where the Schuler SMG high-speed tryout press offers immense advantages. Author Keywords: Hydraulic high-speed tryout press; Simulation; Reproducibility; Speed profile; Development; Press characteristics; Forming behaviour; Die; Drawing; Spotting; Slide tilting; Drive system; Cost and time savings Article Outline 1. Introduction 2. Hydraulic high-speed tryout press 3. Slide speed profile 4. Slide tilting 5. Drive systems 6. Efficiency 7. Example of hydraulic high-speed tryout press 1. Introduction The new generation of Schuler SMG hydraulic high-speed simulation presses is capable of reproducing the production process in the early die development stage and under conditions almost identical to the existing production conditions. This is possible due to the good reproducibility of the relevant press characteristics. The parameters obtained during simulation on the tryout press (e.g., speeds and die cushion characteristics) can be directly transferred to the production press. The die tryout on hydraulic high-speed presses shortens considerably the time that is needed for testing the dies in the production press (Fig. 1). Fig. 1. Die maker during die tryout on the hydraulic high-speed press. 2. Hydraulic high-speed tryout press The focus of the new innovative press concept was the tryout of production dies in the production environment. The main task was the consideration of mechanical production presses and their specific features. The relevant press characteristics of the simulation press must correspond to the production press characteristics. The most important features are the speed characteristics of the slide motion and the slide tilting values, the behaviour of die cushions and the static press values (the deflection of the bolster and slide, the deformation of press uprights). Result of the development was the new generation of hydraulic high-speed tryout presses. These presses have the ability to simulate the forming behaviour of different mechanical press types and brands with various drive systems and specific characteristics of slide motion. One single Schuler SMG hydraulic high-speed tryout press can cover the die tryout for a wide range of production presses, and can therefore substitute for all the previously required conventional tryout presses. In addition to the simulation of the loads and motions of mechanical presses, the hydraulic high-speed press offers the flexibility and advantages of conventional hydraulic tryout presses such as: (i) accurate load adjustments; (ii) maximum load over the whole press stroke possible; (iii) easy adjustment of stroke and die space (BDC and TDC); (iv) teach in function for all relevant switch points; (v) inching mode for the slide; (vi) reversal function at any point of the stroke; (vii) die spotting mode controlled by joystick; (viii) flexible slide locking system over the whole stroke; (ix) low maintenance costs. The hydraulic high-speed tryout press can be equipped with various peripheral equipment such as moving bolsters, bed and slide cushions with one- or multi-point control, blankholder (for double action press), rotating slide plate, external die lifters and turning stations and quick die change systems (Fig. 2). Fig. 2. High-speed tryout press with accumulator drive, four-point cushion, parallelism control, die cushion pre-acceleration and slide stroke limitations. Modern control technology is available for process monitoring, data saving and data transfer of the parameters obtained during tryout. 3. Slide speed profile The speed profile of the Schuler SMG hydraulic high-speed tryout press is freely programmable. The data of a knuckle joint or eccentric press is entered in a spreadsheet (crankshaft to slide position and slide stroke) on the control of the high-speed tryout press. Dependent on the number of strokes to be simulated, the effective slide speeds are adjusted by the control system. The slide speed is infinitely adjustable to any stroke profile of the mechanical slide motion by a highly dynamic servo-hydraulic system and a separate high-performance control circuit (servo-control valves). With the use of hydraulic accumulators, slide speeds of 500?mm/s and higher can be reached. This ensures that the slide profile of the drawing station and the follow-up forming stations of mechanical production presses can all be simulated. Furthermore, the impact on the mechanical production presses which are equipped with pre-accelerated die cushions can be simulated, even without requiring die cushion pre-acceleration on the tryout press (Fig. 3). However, for exact simulation of the blank behaviour prior to the impact, a pre-accelerated die cushion is recommended. Fig. 3. Pressure profile of high-speed tryout press with and without a pre-accelerated die cushion. The motion profile of mechanical production presses can be exactly simulated. The motion sequence on a high-speed tryout press is as follows: (1) rapid approach; (2) braking up to a predefined position (stroke-dependent); (3) switch-over to working speed and start of simulation; (4) end of simulation in BDC; (5) pressure relief and slide retraction. The possible slide retraction speed is between 300 and 500?mm/s. Therefore the undesired effect of vacuum sticking of the drawn part due to the quick slide retraction can be simulated during the slide retraction. Following such tests, required aeration holes can be made at an early die production stage. The whole speed and force profile of the slide can be visualised on the control screen (selected profile and performed profile). 4. Slide tilting The slide tilting values of mechanical presses are dependent on the load eccentricity and the press force. The connecting rods bear the main load to keep the slide parallel to the bolster. The slide guiding must only compensate for low forces. Due to the compression of the oil columns in the pressure cylinders, slide parallelism on hydraulic presses depends much more on the slide guiding. In order to achieve similar tilting values as on mechanical presses, the guiding system and the press uprights must be designed accordingly. Larger tilting values can only be compensated for by the use of active parallelism control systems in the x–x and y–y directions. Advantage of such a system: tilting values of mechanical presses can be pre-set and simulated. This is especially beneficial for large sheet panels (e.g., side panel tools) where higher eccentric loads can be expected. For the spotting of dies, adjustable mechanical slide stroke limitations are used which eliminate any slide tilting during tool contact. The sensitive die spotting control by joystick enables the closing of dies with reduced force and a controllable closing speed in the range 5–35?mm/s. 5. Drive systems The drive system of a Schuler SMG high-speed tryout press is based on accumulator technology. Nitrogen cylinders supply energy to piston accumulators which deliver the oil to the slide cylinders. The valves for speed control are located between the piston accumulators and the slide cylinders. As an example, a press with 20?000?kN capacity requires only a main drive rating of 250?kW. The standard design of accumulators and charging pump is suitable for approximately two simulation strokes per minute. The tryout press can be designed for up to approximately 30?000?kN maximum press capacity. 6. Efficiency The purpose of using hydraulic high-speed presses for tryout is the saving of production capacities or, in other words, the reduction of tryout time on the production presses. A mechanical tryout press can only simulate the production press for which it was designed in terms of slide speed characteristic (drive system) and drawing cushion system. Although the transferability of the results is even better, the machine costs are much higher than for hydraulic tryout presses. Furthermore, one hydraulic high-speed tryout press can simulate the forming behaviour of different press brands and press types (hydraulic or mechanical) with different characteristics of slide motion (Fig. 4). Fig. 4. Example of time and cost saving with hydraulic high-speed tryout presses compared with conventional hydraulic presses. For an ordinary die for side panels, the tryout time needed in the production press can be up to 6 weeks. Experiences have shown that this time can be shortened by up to 80% using the high-speed tryout presses described above. The amortisation time is rather short considering the various applications of these presses, especially when taking into account the high-hourly rates of mechanical crossbar and GT-presses of up to $3000. 7. Example of hydraulic high-speed tryout press The Schuler SMG hydraulic high-speed tryout presses shown in Fig. 5 were built for an American automobile manufacturer. Each press has a capacity of 18?000?kN and is equipped with moving bolster, rotating slide plate, four-point controlled pre-accelerated die cushion, stroke limitations and hydraulic die clamping system. Fig. 5. Hydraulic high-speed tryout presses with moving bolster and rotating slide plate. The slide motion profiles and slide speeds, the die cushion set-up and the mechanical characteristics ensure that an almost identical simulation of the production conditions of mechanical large-panel crossbar presses can be made. A highly sophisticated control system allows comfortable input of the variable target data, direct monitoring of the tryout process with digital and graphic display of the relevant parameters, data storage and data transfer. 附錄Ⅱ 外文文獻翻譯 用于機械成型加工模擬的液壓高速沖壓機 摘要 模具的試驗在模具的制造業(yè)和常規(guī)生產(chǎn)過程中起重要作用。 盡管有了CAD仿真,新模具的試驗仍然需要很多時間和工作。費時的測試經(jīng)常受昂貴的生產(chǎn)線約束，因為他們不同的特性導致在制模工廠使用的沖壓機不能提供反復生產(chǎn)產(chǎn)品所需壓力的精確特性。同樣的情形也存在于模具改革和模具修復中。很有可能在比較完善的產(chǎn)品生產(chǎn)之前就已經(jīng)花費了很多時間了，這反過來又影響生產(chǎn)力和生產(chǎn)設備的效率。 伴隨著汽車模型品種增加引起的規(guī)?？s減，模具徹底改革的次數(shù)也增加了，從而縮短調(diào)整工時，為成本的減少提供了很大的潛力。這是Schuler SMG 高速試驗沖壓機具有的特大優(yōu)點。 作者主題詞：液壓高速試驗沖壓機；仿真；反復生產(chǎn)能力；速度曲線；發(fā)展；壓力特性；成形；模具；沖壓成形；點位；導軌傾斜；驅(qū)動系統(tǒng)；節(jié)約成本和時間 文章大綱 1．介紹 2．液壓高速試驗沖壓機 3．滑動速度曲線 4．導軌傾斜 5．驅(qū)動系統(tǒng) 6．效率 7．液壓高速試驗沖壓機實例 1.介紹 在早期的模具發(fā)展階段，或者在與現(xiàn)有的生產(chǎn)條件幾乎相同的情況下，Schuler SMG的新一代液壓高速模擬沖壓機能夠再現(xiàn)生產(chǎn)過程。這可能是歸因于相關壓力特性的良好再現(xiàn)能力。這些參數(shù)是在液壓高速試驗沖壓機的模擬期間獲得的(即，速度和模具緩沖裝置特性)，而且它們可以直接轉(zhuǎn)換成生產(chǎn)所需壓力。 對液壓高速沖壓機的試驗很大程度上縮短了在生產(chǎn)沖壓機過程中測試模具所花的時間(如圖1)。 2.液壓高速試驗沖壓機 新型創(chuàng)新沖壓機概念的焦點在于生產(chǎn)環(huán)境中模具產(chǎn)品的試驗。其主要任務是考慮機械式?jīng)_壓機及其特殊性能。模擬沖壓機的相關壓力特性必須與成品沖壓機的相關特性一致。其中，最重要的特點是滑動的速度和導軌的傾斜值，還有模具緩沖裝置的性能和靜態(tài)壓力值(模墊和導軌的偏斜,沖壓機立柱的變形)。 隨著技術發(fā)展，就出現(xiàn)了新一代液壓高速試驗沖壓機。這些沖壓機能夠模擬不同機械式?jīng)_壓機類型的成形性能，而且能夠與各種各樣的驅(qū)動系統(tǒng)及導軌運動的特殊參數(shù)吻合。單一的一臺Schuler SMG液壓高速試驗沖壓機能夠大范圍地代表模具試驗的結(jié)果，所以也就代替所以的早先需要的傳統(tǒng)試驗沖壓機。 除了對機械式?jīng)_壓機的裝載和運動進行模擬之外，液壓高速沖壓機也具有傳統(tǒng)試驗沖壓機的靈活性和優(yōu)點，例如：(i) 精確裝載調(diào)節(jié)；ii) 整個沖壓機行程中允許的最大載荷；(iii) 調(diào)整行程和型腔的簡便性(BDC 和TDC)；(iv) 所有相關轉(zhuǎn)換節(jié)點的提示功能；(v) 滑動的緩進給模型；(vi) 沖程中任意點的逆轉(zhuǎn)功能；(vii) 由操縱桿控制的模型定位模式；(viii) 在整個沖程中靈活的制動裝置；(ix) 低維修費用。 液壓高速試驗沖壓機能夠配以各種各樣的外部設備，譬如可移動的模墊，床身和一點或多點控制的導軌墊，壓邊導軌(雙動壓力機),可轉(zhuǎn)動的導軌，外部拔模裝置，回轉(zhuǎn)站和模具快速切換系統(tǒng)(如圖2)。 在試驗期間，現(xiàn)代控制技術對于程序控制、數(shù)據(jù)保存和所得參數(shù)的轉(zhuǎn)換是有效的。 3.滑動速度曲線 Schuler SMG液壓高速試驗沖壓機的速度曲線是可以通過編程自由控制的。在控制高速試驗沖壓機時，精壓機和離心沖壓機的數(shù)據(jù)是在一個電子數(shù)據(jù)表輸入的(曲軸滑動的位置和滑動沖程)。由于取決于模擬的沖程數(shù)目，那就可以通過控制系統(tǒng)有效的滑動速度。通過一個高度動態(tài)的液壓伺服系統(tǒng)和一個獨立的高性能控制電路(伺服操縱閥門)，對于機械式滑動的任意沖程曲線，滑動的速度就可以無限地調(diào)整了。 隨著液壓蓄能器的使用，可以達到500°mm/s或者更高的速度。這就確保了沖壓成形站的滑動曲線和接下來的機械成品沖壓機的成型站均能被模擬。 而且，配有預加速的模具緩沖裝置的機械成品沖壓機的沖擊就可以進行仿真了(如圖3)。但是,在進行坯件性能的精確仿真之前，建議對模具緩沖裝置預加速。 高速試驗沖壓機的運動序列如下：(1) 快捷方法；(2) 對預定義的位置制動(由沖程決定)；(3) 轉(zhuǎn)換到工作速度并開始仿真；(4) 在BDC中仿真結(jié)束；(5) 壓力曲線和導軌升降。 導軌允許的升降速度在300～500°mm/s之間。所以在導軌升降過程中，導軌快速升降引起的真空粘附的干擾影響也能夠模擬了。經(jīng)過這樣的測試以后，就可以在模具生產(chǎn)的早期階段制造所需的排氣孔。 到軌的整體速度和受力曲線可以控制屏上顯示(精選的曲線和執(zhí)行曲線)。 4.導軌傾斜 機械式?jīng)_壓機的導軌傾斜值取決于加載偏心度壓力值。連接桿承擔主要載荷以保持導軌平行于壓床墊板。導軌引導只須在低壓時給予補償即可。在壓力圓筒中由于油柱的壓縮，在液壓沖壓機中，導軌的平行性更加取決于導軌引導。為了達到和機械式?jīng)_壓機相類似的傾斜值，必須相應地設計引導系統(tǒng)和沖壓機立柱。如果需要更大的傾斜值，那就得通過使用xx和y-y方向平行性自動控制系統(tǒng)來補償實現(xiàn)。 這樣一個系統(tǒng)的好處有：機械式?jīng)_壓機的傾斜值可以預先進行設定并進行模擬。對于期望具有更高偏心度載荷的大薄板工件來說，這就特別有利了(即，側(cè)板工具)。 對于模具定位，使用了可調(diào)機械式導軌沖程限制，這樣，在與沖頭接觸時就可以消除任意的導軌傾斜值。由控制桿控制的靈敏的模具定位控制，能夠用較小的力使模具閉合，而且在5-35°mm/s的范圍內(nèi)可以控制閉合速度。 5.驅(qū)動系統(tǒng) Schuler SMG高速試驗沖壓機的驅(qū)動系統(tǒng)是基于蓄能器技術的。氮氣筒提供能量給活塞蓄能器，它再把油傳輸給導軌油缸。速度大小的控制裝置是定位在活塞蓄能器和導軌油缸之間的。舉例來說明一下，一個20000kN供油量的沖壓機只需一個額定值為250KW的主驅(qū)動就可以了。蓄能器和進料泵的標準設計適合大概每分鐘兩個模擬沖程。而試驗沖壓機可以被設計為大約30000kN的最大沖壓機供油量。 6.效率 使用液壓高速沖壓機來試驗的目的為了提高生產(chǎn)能力，換句話說，也是減少花在成品沖壓機試驗上的時間。 一臺機械試驗沖壓機只能模擬根據(jù)滑動速度特性(驅(qū)動系統(tǒng))和沖壓緩沖系統(tǒng)設計的成品沖壓機。盡管它結(jié)果的移植性好得多，但是它機器的成本比液壓高速試驗沖壓機高得多。而且，液壓高速試驗沖壓機能夠通過不同的滑動特性來模擬不同銘牌和不同類型的沖壓機的成型性能(液壓或機械)(如圖4)。 對于一個側(cè)板的普通的模具來說，在成品沖壓機生產(chǎn)過程中需要的試驗時間可能會達到6個星期。而經(jīng)驗表明，這試驗時間可以通過使用上面描述的高速試驗沖壓機來使其縮短到80%?？紤]到這些沖壓機的各種各樣的應用，這攤下來的時間就更短了，特別是當考慮到機械交叉壓力或GT壓力變化率高達每小時$3000的時候。 7. 液壓高速試驗沖壓機實例 在圖5中顯示了Schuler SMG液壓高速試驗沖壓機廠被設為美國汽車制造商。每臺沖壓機有18000kN的容量并配以可移動的壓床墊板，可轉(zhuǎn)動的導軌，四點控制的預加速模具緩沖裝置，沖程限制和液壓模具裝夾系統(tǒng)。 導軌運動曲線和導軌的速度，模具緩沖裝置及其機械特性，這些就保證了機械大型縱橫式?jīng)_壓機的生產(chǎn)條件可以進行幾乎一致的模擬。 一個高精度的控制系統(tǒng)允許對可變的目標數(shù)據(jù)進行合適的輸入，并對其相關參數(shù)，數(shù)據(jù)存儲和數(shù)據(jù)傳輸?shù)臄?shù)字顯示和圖表顯示進行直接監(jiān)控。