發(fā)布時(shí)間：2018-06-18 04:52

  本文選題：選區(qū)激光熔化 + 拼接成形��； 參考：《浙江工業(yè)大學(xué)》2016年碩士論文

【摘要】：選區(qū)激光熔化技術(shù)(Selective Laser Melting,SLM)是增材制造領(lǐng)域最具發(fā)展?jié)摿Φ募夹g(shù)之一。該技術(shù)利用高能束激光直接作用金屬粉末,成形高致密度的金屬零件。該方法能成形傳統(tǒng)加工無法制造的復(fù)雜結(jié)構(gòu),在航空航天、生物醫(yī)學(xué)及復(fù)雜模具等方面有廣泛應(yīng)用。但目前SLM成形技術(shù)在制造精度及成本控制等存在較多問題,對(duì)某些既有高制造精度、又存在個(gè)性化復(fù)雜結(jié)構(gòu)的零件,僅單一傳統(tǒng)加工或SLM成形均存在困難。為此,本文提出在機(jī)加工零件上成形個(gè)性化復(fù)雜結(jié)構(gòu),充分結(jié)合兩種加工方式的優(yōu)勢(shì)。首先本文制定基本工藝路線并進(jìn)行預(yù)實(shí)驗(yàn)研究,在此基礎(chǔ)上提出實(shí)驗(yàn)方案。在SLM成形倉(cāng)定位中,確定機(jī)加工基體、基板和CAD零件的相互空間位置關(guān)系,設(shè)計(jì)并實(shí)現(xiàn)了定位方式及定位誤差控制。對(duì)基體SLM成形過程進(jìn)行溫度場(chǎng)仿真,研究等能量密度輸入下激光功率、掃描速度對(duì)單道成形、熔池溫度效應(yīng)擴(kuò)散的影響;提出以優(yōu)化分區(qū)大小掃描的面熱流方式,減少成形區(qū)面附近粘粉,研究面能量輸入對(duì)面成形的溫度擴(kuò)散問題。在上述仿真和分析的基礎(chǔ)上,實(shí)驗(yàn)研究中通過控制等線能量密度輸入,解決了單道熔池不連續(xù)和有飛濺球化顆粒、面成形時(shí)球化現(xiàn)象嚴(yán)重以及面上有細(xì)小裂紋等問題。獲得了激光功率和速度匹配合適時(shí)穩(wěn)定的單道熔池及平整無明顯裂紋的成形表面。最后在控制激光輸入和掃描速度的基礎(chǔ)上,實(shí)現(xiàn)了拼接實(shí)體成形。金相組織分析結(jié)果表明,成形熔池與基體有較好的冶金結(jié)合。同時(shí)提出了通過重熔實(shí)體的方法,增加結(jié)合面處熔池?cái)?shù)量,提高結(jié)合面金屬的結(jié)合能力。維式微觀硬度表明,由于后加工層對(duì)前一層有熱傳導(dǎo)作用,SLM成形頂面向下硬度逐漸降低。拉伸性能實(shí)驗(yàn)表明,能量輸入速度對(duì)結(jié)合面拉伸極限強(qiáng)度有著顯著影響。
[Abstract]:Selective Laser melting (SLM) is one of the most promising technologies in the field of material augmentation. The technology uses high energy beam laser to directly affect metal powder to form high density metal parts. This method can form complex structures which can not be manufactured by traditional machining, and has been widely used in aerospace, biomedicine and complex mould. However, there are many problems in SLM forming technology, such as manufacturing precision and cost control. It is difficult for some parts with high manufacturing accuracy and complex structure, only single traditional machining or SLM forming. Therefore, this paper puts forward the advantages of forming individualized complex structures on machined parts and fully combining the two kinds of machining methods. First of all, the basic technological route is established and the experimental scheme is put forward on the basis of pre-experimental research. In the positioning of SLM forming warehouse, the spatial position relationship of machined matrix, substrate and CAD parts is determined, and the positioning mode and positioning error control are designed and realized. The influence of laser power and scanning speed on single pass forming and temperature diffusion of molten pool was studied by simulating the temperature field of SLM matrix forming process, and the surface heat flux mode was proposed to optimize the scanning area size. The temperature diffusion problem of the surface energy input is studied by reducing the adhesive powder near the forming area. On the basis of the above simulation and analysis, by controlling the input of equal line energy density, the problems of single channel melting pool discontinuity and spattering particles, the serious spheroidization phenomenon and the small cracks on the surface are solved in the experimental study. A stable single-pass molten pool with a suitable laser power and velocity matching is obtained and the formed surface without obvious cracks is formed. Finally, on the basis of controlling the laser input and scanning speed, the splicing solid forming is realized. The results of metallographic analysis show that the molten pool has a good metallurgical bonding with the matrix. At the same time, the method of remelting the solid is put forward to increase the number of melting pool at the bonding surface and to improve the bonding ability of the metal on the bonding surface. The results of microhardness show that the downward hardness of the top surface of SLM is gradually decreased due to the heat conduction effect of the post-machined layer on the front layer. The tensile tests show that the energy input speed has a significant effect on the ultimate tensile strength of the bonding surface.
【學(xué)位授予單位】：浙江工業(yè)大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2016
【分類號(hào)】：TG665

【參考文獻(xiàn)】

相關(guān)期刊論文 前10條

1 李凱;劉琳;;舌側(cè)矯治技術(shù)研究進(jìn)展[J];中國(guó)實(shí)用口腔科雜志;2014年02期

2 盧秉恒;李滌塵;;增材制造(3D打印)技術(shù)發(fā)展[J];機(jī)械制造與自動(dòng)化;2013年04期

3 王典;賈蕾;葛小兵;;316L粉末間接激光燒結(jié)的工藝參數(shù)對(duì)溫度場(chǎng)的影響[J];機(jī)械設(shè)計(jì)與制造工程;2013年07期

4 何福明;趙士芳;;口腔種植系統(tǒng)研發(fā)現(xiàn)狀[J];浙江大學(xué)學(xué)報(bào)(醫(yī)學(xué)版);2012年03期

5 李瑞迪;魏青松;劉錦輝;史玉升;袁鐵錘;;選擇性激光熔化成形關(guān)鍵基礎(chǔ)問題的研究進(jìn)展[J];航空制造技術(shù);2012年05期

6 任繼文;殷金菊;;選擇性激光燒結(jié)金屬粉末瞬態(tài)溫度場(chǎng)模擬[J];機(jī)床與液壓;2012年01期

7 楊永強(qiáng);盧建斌;王迪;羅子藝;;316L不銹鋼選區(qū)激光熔化成型非水平懸垂面研究[J];材料科學(xué)與工藝;2011年06期

8 王迪;楊永強(qiáng);何興容;吳偉輝;蘇旭彬;王紅衛(wèi);;316L不銹鋼粉末光纖激光選區(qū)熔化特性[J];強(qiáng)激光與粒子束;2010年08期

9 吳偉輝;楊永強(qiáng);王迪;黃偉紅;;選區(qū)激光熔化變密度快速制造工藝研究[J];中國(guó)激光;2010年07期

10 薛蕾;黃一雄;盧鵬輝;陳靜;林鑫;黃衛(wèi)東;;激光成形修復(fù)ZL104合金的組織與性能研究[J];中國(guó)表面工程;2010年01期

，

本文編號(hào)：2034176