【摘要】：在粉末冶金生產(chǎn)實踐中，裝備水平是制約產(chǎn)品密度和精度的重要因素。針對目前國內(nèi)粉末成形裝備中存在的結(jié)構(gòu)復(fù)雜、體積較大，設(shè)備成本較高等不足之處；本文提出的研究目標(biāo)是：研制一種粉末精密成形專用設(shè)備，集成上二下三模架，通過集成的油缸驅(qū)動，結(jié)合閉環(huán)控制，能成形高精度、高密度且密度分布均勻的復(fù)雜粉末冶金零件。 本文為研制出新型粉末精密成形設(shè)備提出了集成模架設(shè)計方案，它實現(xiàn)壓機與模架集成化設(shè)計，使得設(shè)備結(jié)構(gòu)簡單，調(diào)試方便，能最大限度發(fā)揮粉末成形專用設(shè)備的特點，提高成形精度，降低設(shè)備價格。針對模架集成式粉末成形設(shè)備設(shè)計，首先對粉末壓制過程中粉末的本構(gòu)模型進行力學(xué)建模，提出一種更符合實驗結(jié)果的的粉末材料流動應(yīng)力模型，獲得壓制過程的載荷；并以此為基礎(chǔ)，通過數(shù)值模擬方法，研究在典型粉末冶金零件的壓制成形過程中,壓制載荷對粉末精密成形設(shè)備的影響，實現(xiàn)對設(shè)備結(jié)構(gòu)設(shè)計方案校核；并針對模架集成式粉末精密成形設(shè)備的特點設(shè)計制造液壓系統(tǒng)，綜合壓機本體和液壓系統(tǒng)設(shè)計制造配套的控制系統(tǒng)，編制控制軟件，并實現(xiàn)了樣機研制，并取得以下研究成果： 首先要取得壓制過程設(shè)備的載荷，通過對粉末壓制過程中粉末力學(xué)模型進行研究，推導(dǎo)出橢球形粉末屈服準(zhǔn)則，以實現(xiàn)粉末壓制過程的數(shù)值模擬，分別模擬計算粉末壓制過程的載荷－行程曲線，通過實驗和模擬的載荷－行程曲線的對比，分析粉末壓制過程中流動應(yīng)力的變化。結(jié)合粉末進行壓制實驗，對結(jié)果進行分析、整理，考慮了Doraivelu的流動應(yīng)力模型對δ(ρ)的量綱分析，提出用于模架集成式粉末成形設(shè)備設(shè)計的流動應(yīng)力模型。 采用該模型模擬圓柱試樣的壓制過程，計算粉末壓制的載荷-行程曲線,實驗結(jié)果表明，該模型更貼近粉末力學(xué)行為。采用該模型計算粉末壓坯的相對密度分布,與實驗值比較,表明該模型模擬的結(jié)果較為可靠。采用上述流動應(yīng)力模型，模擬了典型零件的粉末壓制過程，為下一步模架集成式粉末成形設(shè)備成形加載提供基礎(chǔ)數(shù)據(jù)。 基于多體動力學(xué)數(shù)值模擬方法，建立了模架集成式粉末成形設(shè)備整機接觸分析的有限元計算模型，進行了粉末成形設(shè)備整機結(jié)構(gòu)強度與剛度分析，得出了整機及其各子結(jié)構(gòu)的變形和應(yīng)力分布云圖，從變形云圖中可以得出，各個模板的最大變形撓度均在安全范圍之內(nèi)。將各子結(jié)構(gòu)的最大應(yīng)力值與其材料的屈服極限進行比較后，可知各零件仍處于彈性變形范圍之內(nèi)，沒有發(fā)生屈服；計算結(jié)果對于結(jié)構(gòu)優(yōu)化設(shè)計具有理論指導(dǎo)作用。 對模架集成式粉末成形設(shè)備進行模態(tài)分析，得到各階固有頻率及對應(yīng)的固有振型。提取前10階固有頻率及對應(yīng)的固有振型。設(shè)備模態(tài)分析計算結(jié)果表明，設(shè)備的各階模態(tài)頻率之間沒有重疊，不會產(chǎn)生共振，各階模態(tài)的變形趨勢�。粡挠嬎憬Y(jié)果來看，可以看出整機的固有頻率對整機振動的影響，顯示出了整機各部分結(jié)構(gòu)振動的強弱分布以及抗振薄弱區(qū)，為減少模架集成式粉末成形設(shè)備振動和噪聲提供了可靠的依據(jù)，為成形設(shè)備結(jié)構(gòu)動力學(xué)優(yōu)化設(shè)計提供了必要的依據(jù)。 對模架集成式粉末成形設(shè)備的液壓及控制系統(tǒng)進行研究，液壓傳動回路中使用插裝閥回路、電液比例閥，與光柵尺、壓力傳感器構(gòu)成控制回路，實現(xiàn)每個沖頭都能獨立進行精確的連續(xù)軌跡控制，在壓制各臺面之間高度差別大的多臺面零件時，能夠使各沖頭在壓制過程中保持近乎一致的高度變化速率，以較高的工作效率和較高的成形精度壓制出密度均勻的粉末零件。 成功研制了模架集成式粉末成形設(shè)備樣機，并成功實現(xiàn)典型零件加工試制，設(shè)備滿足設(shè)計要求，所提出的用于模架與粉末成形設(shè)備相集成的設(shè)計方案改變傳統(tǒng)設(shè)備的結(jié)構(gòu)，能最大限度發(fā)揮粉末成形專用設(shè)備的特點，并形成自主知識產(chǎn)權(quán)。該設(shè)備的模架由對稱分布的集成油缸驅(qū)動，獨立控制多個模沖實現(xiàn)上二、下三多臺面復(fù)雜零件的壓制。采用光柵尺、傳感器和液壓系統(tǒng)組合，，檢測模沖位置和壓力，能進行精確閉環(huán)控制，設(shè)備精度達到±0.03mm。
[Abstract]:In the production practice of powder metallurgy, the equipment level is an important factor to restrict the density and precision of the product. aiming at the defects of complex structure, large volume, high equipment cost and the like existing in the present domestic powder forming equipment, the aim of the invention is to develop a special equipment for powder precision forming, the invention can be used for forming complex powder metallurgy parts with high precision, high density and uniform density distribution. In this paper, a new type of powder precision forming equipment is designed, and the integrated design of the press and the die base is realized, so that the equipment is simple in structure and convenient to debug, and the characteristics of the special equipment for powder forming can be played to the maximum extent, the forming precision is improved, and the price of the equipment is reduced. The invention aims at the equipment design of an integrated powder forming device of a die frame, firstly, carrying out mechanical modeling on the structure model of the powder in the powder pressing process, and providing a powder material flow stress model which is more in line with the experimental results, and obtaining the load of the pressing process; and based on the model, the numerical simulation side In this paper, the influence of the pressing load on the powder precision forming equipment is studied in the process of pressing and forming of the typical powder metallurgy parts, and the design scheme of the equipment is checked; and the hydraulic system is designed for the characteristics of the integrated powder precision forming equipment of the die frame. The control system for the design and manufacture of the main body and the hydraulic system of the system, the integrated press body and the hydraulic system is designed, the control software is developed, and the development of the prototype is realized, and the following research is made: The method comprises the following steps of: firstly, obtaining the load of the pressing process equipment, and feeding the powder mechanical model in the powder pressing process; In this paper, the yield criterion of the ellipsoidal powder is derived, the numerical simulation of the powder pressing process is realized, the load-stroke curve of the powder pressing process is simulated respectively, and the flow stress in the powder pressing process is analyzed by the comparison of the experiment and the simulated load-stroke curve. In this paper, the results are analyzed and sorted, and the dimensional analysis of the flow stress model of the Dvortexu is taken into account, and the flow of the integrated powder forming equipment for the die set is put forward. The force model is used to simulate the pressing process of the cylindrical sample, and the load-stroke curve of the powder pressing is calculated. The experimental results show that the model is closer to the powder. The relative density distribution of the powder compact is calculated by using the model, and the simulation results are compared with the experimental values. The flow stress model is adopted, the powder pressing process of a typical part is simulated, and the forming and loading lifting of the integrated powder forming equipment of the next step is provided. Based on the multi-body dynamics numerical simulation method, the finite element calculation model of the contact analysis of the integrated powder forming equipment of the die set is established, and the structural strength and the rigidity analysis of the whole machine of the powder forming equipment are analyzed, and the deformation of the whole machine and the sub-structures of the whole machine is obtained. and the maximum deformation deflection of each template is In the safe range, the maximum stress value of each sub-structure is compared with the yield limit of the material, so that the parts are still in the elastic deformation range, and the yield is not generated; and the calculation result is good for the structural optimization design. The mode analysis is carried out on the integrated powder forming equipment of the die set to obtain the inherent frequency of each order. rate and corresponding natural mode. The first 10-order intrinsic frequency is extracted The results of the modal analysis of the equipment show that there is no overlap between the modal frequencies of the equipment, the resonance is not generated, the deformation trend of each mode is small, and the inherent frequency of the whole machine can be seen from the calculation results. The influence of the rate on the vibration of the whole machine shows the strong and weak distribution of the vibration of each part of the whole machine and the weak area of the anti-vibration, and provides a reliable basis for reducing the vibration and noise of the integrated powder forming equipment of the die set, and the structure dynamics of the forming equipment is optimized. The necessary basis is provided. The hydraulic and control system of the integrated powder forming equipment of the formwork is studied. The hydraulic transmission circuit uses the plug-in valve circuit, the electro-hydraulic proportional valve, the pressure sensor and the pressure sensor to form the control loop, so that each punch can be independent. the precise continuous track control is carried out, and when the multi-table part with large height difference is pressed between the pressing surfaces, the punch can keep a nearly uniform height change rate in the pressing process, and the high working efficiency and the higher forming precision pressure can be achieved. The powder parts with uniform density were manufactured successfully. The prototype of the integrated powder forming equipment of the die set was successfully developed, and the typical part processing and trial production were successfully realized. The equipment met the design requirements, and the proposed method was used for the integration of the die set and the powder forming equipment. The design scheme changes the structure of the traditional equipment, and can give full play to the special equipment for powder forming. The mould base of the equipment is driven by an integrated oil cylinder with a symmetrical distribution, and an accurate closed-loop control can be carried out by adopting a combination of a grating ruler, a sensor and a hydraulic system, detecting the position and the pressure of the die,
【學(xué)位授予單位】：華南理工大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2014
【分類號】：TF37

【參考文獻】

相關(guān)期刊論文 前10條

1 程遠方,果世駒,賴和怡;球形顆粒隨機排列過程的計算機模擬[J];北京科技大學(xué)學(xué)報;1999年04期

2 賀峻,康永林,任學(xué)平;粉末構(gòu)件CIP成形過程有限元數(shù)值模擬[J];材料科學(xué)與工藝;1999年S1期

3 賀峻,康永林,任學(xué)平;數(shù)值模擬在陶瓷粉末材料冷等靜壓過程中的應(yīng)用[J];材料科學(xué)與工藝;2002年01期

4 朱春霞;朱立達;劉永賢;蔡光起;;并聯(lián)機器人多柔體系統(tǒng)協(xié)同建模與動力學(xué)仿真[J];東北大學(xué)學(xué)報(自然科學(xué)版);2008年03期

5 汪俊，李從心;金屬粉末體壓制成形過程模型的研究[J];鍛壓機械;1996年02期

6 董建東,熊曉紅,黃樹槐;國內(nèi)外粉末冶金壓力機的研究與應(yīng)用[J];鍛壓機械;1998年04期

7 郁建明,姜建國,陸汝恒;粉末冶金結(jié)構(gòu)零件常用壓形方法與設(shè)備選擇[J];粉末冶金工業(yè);1994年01期

8 羅鳴;先進的壓制技術(shù)與具有智能的德國柯美佳(KOMAGE)壓機[J];粉末冶金工業(yè);1995年06期

9 董建東,熊曉紅,黃樹槐;粉末冶金壓機的應(yīng)用與進展[J];粉末冶金工業(yè);1998年02期

10 華林,毛華杰,趙仲治;粉末冶金鍛造變形力和密度計算[J];粉末冶金工業(yè);2000年01期

相關(guān)博士學(xué)位論文 前1條

1 王德廣;金屬粉末高致密化成形及其數(shù)值模擬研究[D];合肥工業(yè)大學(xué);2010年

本文編號：2418130