本文選題：微束等離子弧 + 快速成形　； 參考：《哈爾濱工業(yè)大學(xué)》2014年碩士論文

【摘要】：微束等離子弧（MPA）快速成形（RP）采用低于30A的等離子弧作為熱源，金屬焊絲作為填充材料，依逐層累加的原理實(shí)現(xiàn)金屬的直接成形。本文以平板一維約束下的MPA-RP為研究對(duì)象，以優(yōu)化成形工藝、提高成形質(zhì)量為目標(biāo)，在搭建實(shí)驗(yàn)系統(tǒng)與確定成形參數(shù)的基礎(chǔ)上建立了多重堆積層間尺寸預(yù)測(cè)模型，研究并優(yōu)化了道間搭接工藝。最后，采用數(shù)值模擬的方法以翹曲變形最小為目的，對(duì)多重堆積層間與道間堆積路徑進(jìn)行優(yōu)化，確保成形質(zhì)量。 首先，設(shè)計(jì)并實(shí)現(xiàn)了快速成形實(shí)驗(yàn)系統(tǒng)。整個(gè)系統(tǒng)由三維運(yùn)動(dòng)平臺(tái)、焊接設(shè)備、堆積層尺寸檢測(cè)設(shè)備及相應(yīng)控制軟件組成。完成相關(guān)設(shè)備標(biāo)定，確定送絲速度v2、堆積電流I與堆積速度v1工藝參數(shù)間成形匹配關(guān)系。確定多層堆積層間溫度為100℃。 針對(duì)于單道多層堆積，采用二次正交回歸旋轉(zhuǎn)組合設(shè)計(jì)的方法建立堆積各層尺寸與上述工藝參數(shù)及層次數(shù)n之間的二次回歸方程模型。采用統(tǒng)計(jì)性檢驗(yàn)的方法驗(yàn)證該方程模型對(duì)多層堆積尺寸預(yù)測(cè)的有效性。以此為基礎(chǔ)進(jìn)行定寬度變參數(shù)下的單道多層堆積成形實(shí)驗(yàn)。堆積層與模型最大偏差為7%且出現(xiàn)于第一層，模型預(yù)測(cè)與實(shí)際堆積結(jié)果吻合效果良好。 建立多道單層成形軌跡搭接模型，分析軌跡截面寬高比λ、道間距l(xiāng)對(duì)搭接率η和成形質(zhì)量的影響規(guī)律。進(jìn)行不同寬高比λ下的搭接實(shí)驗(yàn)，實(shí)驗(yàn)結(jié)果與理論推導(dǎo)一致表明：提高寬高比λ有利于成形質(zhì)量的提高，，λ4搭接時(shí)成形缺陷大大降低，搭接層上表面平整度提高。寬高比λ對(duì)成形質(zhì)量的影響是由于不同λ下加熱區(qū)域及金屬填入狀態(tài)不同所致。當(dāng)寬高比增大時(shí)，因液態(tài)金屬表面張力及加熱區(qū)域的變化導(dǎo)致了搭接層上表面平整度的提高。 為優(yōu)化實(shí)際堆積路徑、減小堆積變形，基于MSC. Marc數(shù)值模擬研究了一維平板約束下多重堆積層間與道間堆積方向?qū)寮岸逊e層溫度、應(yīng)力分布和翹曲變形的影響。不同路徑下堆積時(shí)不同的加熱循環(huán)特點(diǎn)使殘余應(yīng)力的分布狀態(tài)不同，最終產(chǎn)生了不同的翹曲變形。經(jīng)對(duì)比分析，多重堆積時(shí)，層間交錯(cuò)異向優(yōu)于同向堆積，道間往復(fù)異向優(yōu)于同向堆積。 最后，將優(yōu)化后的路徑與多層堆積層高落差累積綜合優(yōu)化后進(jìn)行單道多層堆積；與多道堆積時(shí)搭接質(zhì)量影響綜合后進(jìn)行多道單層堆積。實(shí)驗(yàn)結(jié)果表明：模擬優(yōu)化后的路徑與實(shí)際成形工藝結(jié)合后大大降低了堆積層與基板的翹曲變形，保證了多重堆積成形質(zhì)量。
[Abstract]:The plasma arc less than 30 A is used as the heat source and the metal wire as the filling material to realize the direct forming of the metal according to the principle of layer by layer accumulation. In this paper, the MPA-RP with one-dimensional constraint on flat plate is taken as the research object, with the aim of optimizing the forming process and improving the forming quality, a multi-layer interlayer dimension prediction model is established on the basis of setting up the experimental system and determining the forming parameters. The interchannel lap process was studied and optimized. Finally, with the aim of minimizing warpage deformation, numerical simulation is used to optimize the stacking path between multiple stacking layers and paths to ensure the forming quality. Firstly, a rapid prototyping experimental system is designed and implemented. The whole system consists of three-dimensional motion platform, welding equipment, accumulative layer size detection equipment and corresponding control software. Complete the calibration of related equipment, determine the wire feeding speed v2, stacking current I and stacking velocity v1 process parameters forming matching relationship. The temperature between layers is determined to be 100 鈩

本文編號(hào)：1993201