本文關(guān)鍵詞： 熔融沉積成型 生死單元 翹曲變形 應(yīng)力場(chǎng) 溫度場(chǎng)　出處：《昆明理工大學(xué)》2017年碩士論文　論文類型：學(xué)位論文

【摘要】：熔融沉積是近幾十年發(fā)展起來(lái)的一種重要的快速成型制造技術(shù),在藥物醫(yī)療、產(chǎn)品設(shè)計(jì)與開發(fā),模具制造與設(shè)計(jì),藝術(shù)創(chuàng)作中應(yīng)用廣泛。熔融沉積成型技術(shù)中,由于冷卻固化的絲材與高溫絲材粘結(jié)的工藝特點(diǎn),使得沉積層之間產(chǎn)生較大溫度梯度。導(dǎo)致熱塑性絲材因冷卻收縮不一致而產(chǎn)生內(nèi)應(yīng)力。應(yīng)力會(huì)導(dǎo)致制件翹曲變形,開裂,影響制件的精度和質(zhì)量。因此,本文基于簡(jiǎn)化假設(shè)建立應(yīng)力翹曲變形模型。結(jié)合工藝,采用ANSYS對(duì)成型過程中的溫度場(chǎng)和應(yīng)力場(chǎng)進(jìn)行數(shù)值分析,并進(jìn)行溫度測(cè)量實(shí)驗(yàn)。實(shí)現(xiàn)理論,數(shù)值模擬,實(shí)驗(yàn)的相互印證。這不僅具有重要的理論意義,還具有重要的應(yīng)用價(jià)值。本文主要研究?jī)?nèi)容為以下幾點(diǎn):(1)本文首先對(duì)噴頭溫度場(chǎng)進(jìn)行了數(shù)值模擬,結(jié)果表明噴頭為穩(wěn)態(tài)溫度場(chǎng),噴出熔融絲材的溫度為一恒定值。確定了熔融沉積成型瞬態(tài)溫度場(chǎng)的熱源載荷類型。(2)建立了熔融成型過程數(shù)值模擬有限模型,分析了 ABS材料屬性和本構(gòu)關(guān)系。運(yùn)用APDL語(yǔ)言和生死單元技術(shù)對(duì)掃描路徑進(jìn)行設(shè)計(jì),對(duì)載荷和邊界條件的加載方式進(jìn)行了設(shè)置。使得數(shù)值模擬過程能實(shí)現(xiàn)材料沉積,熱源移動(dòng),邊界變化。與真實(shí)加工過程相一致。(3)從分子角度分析了絲材粘結(jié)機(jī)制,研究了應(yīng)力和翹曲產(chǎn)生原因以及界面溫度對(duì)應(yīng)力的影響�；趦�(nèi)應(yīng)力產(chǎn)生機(jī)理,建立了簡(jiǎn)化的應(yīng)力模型和翹曲變形模型,定量地分析出界面溫度和其他因素對(duì)應(yīng)力和翹曲變形的影響。為復(fù)雜的溫度場(chǎng)和應(yīng)力場(chǎng)分析以及工藝分析提供了方向。(4)在5mm/s,10mm/s,15mm/s掃描速度下對(duì)熔融沉積過程的溫度場(chǎng)進(jìn)行數(shù)值模擬,結(jié)果表明了沉積過程中成型件溫度場(chǎng)一般分布規(guī)律。沉積層上節(jié)點(diǎn)的溫度曲線變化呈現(xiàn)一定規(guī)律性,并受到成型室溫度、制件大小、沉積速度,對(duì)流換熱等工藝參數(shù)的影響。其中保證這些工藝參數(shù)都合理的情況下,掃描速度越慢,界面溫度越高。在溫度場(chǎng)分析的基礎(chǔ)上,基于熱彈塑性理論進(jìn)行應(yīng)力場(chǎng)耦合分析,分析了應(yīng)力場(chǎng)分布特點(diǎn)。得到了在不同掃描速度下制件應(yīng)力的大小,掃描速度越慢,應(yīng)力越小。再結(jié)合溫度場(chǎng)結(jié)果,與應(yīng)力模型相互印證。(5)最后,設(shè)計(jì)了熔融沉積成型過程測(cè)溫實(shí)驗(yàn)方案。測(cè)量了噴頭工作時(shí)的溫度值。利用數(shù)據(jù)采集系統(tǒng),在不同掃描速度下,采集了沉積過程中第一層中央位置溫度變化數(shù)據(jù)。并將實(shí)測(cè)結(jié)果處理后與模擬溫度曲線進(jìn)行對(duì)比,實(shí)驗(yàn)與模擬結(jié)果相符合。
[Abstract]:Melt deposition is an important rapid prototyping technology developed in recent decades. It is widely used in medicine, product design and development, mold manufacture and design, art creation. Due to the process characteristics of bonding between the cooling and solidified wire and the high temperature wire, there is a large temperature gradient between the deposited layers, which leads to the internal stress of the thermoplastic wire due to the inconsistency of cooling and shrinkage. The stress will lead to the warping and cracking of the workpiece. Therefore, based on the simplified hypothesis, the stress warping model is established. Combined with the process, the temperature field and stress field in the molding process are analyzed numerically by ANSYS, and the temperature measurement experiments are carried out to realize the theory. Numerical simulation, experimental verification, not only has important theoretical significance, but also has important application value. The main contents of this paper are as follows: 1) the temperature field of nozzle is numerically simulated in this paper. The results show that the nozzle is a steady temperature field and the temperature of the fused wire is a constant value. The heat source load type of the transient temperature field of the melt deposition molding is determined. The finite model of numerical simulation of the melt forming process is established. The properties and constitutive relations of ABS materials are analyzed. The scanning path is designed by using APDL language and birth and death element technology, and the loading modes of load and boundary conditions are set up. The process of numerical simulation can realize material deposition and heat source movement. Boundary change. Consistent with the true processing process, the bonding mechanism of the wire is analyzed from the molecular perspective, and the causes of stress and warpage are studied, as well as the influence of interfacial temperature on the stress. A simplified stress model and a warpage model are established. The effects of interfacial temperature and other factors on stress and warpage deformation are quantitatively analyzed. The results show that the temperature field of the forming parts is generally distributed in the deposition process, and the temperature curve of the nodes on the deposit layer shows a certain regularity, and is affected by the temperature of the molding chamber, the size of the parts, and the deposition rate. The effect of the process parameters, such as convection heat transfer, on the condition that these parameters are reasonable, the slower the scanning speed is, the higher the interface temperature is. Based on the analysis of temperature field, the stress field coupling analysis is carried out based on thermoelastic-plastic theory. The characteristics of stress field distribution are analyzed. The size of the stress of the workpiece is obtained at different scanning speeds. The slower the scanning speed, the smaller the stress. Finally, combining the results of temperature field with the stress model, the results are verified with the stress model. The experimental scheme of temperature measurement in melt deposition molding process was designed. The temperature value of nozzle was measured. The data acquisition system was used to measure the temperature at different scanning velocities. The temperature variation data of the first layer in the process of deposition are collected and the measured results are compared with the simulated temperature curves. The experimental results are in good agreement with the simulation results.
【學(xué)位授予單位】：昆明理工大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：TH16

【參考文獻(xiàn)】

相關(guān)期刊論文 前10條

1 屈晨光;張師軍;高達(dá)利;鄒浩;劉建葉;董穆;郭家梁;邵靜波;呂蕓;;環(huán)境溫度對(duì)3D打印成型精度的影響[J];塑料工業(yè);2015年08期

2 遲百宏;解利楊;高曉東;焦志偉;楊衛(wèi)民;;FDM工藝中構(gòu)建取向?qū)λ芰现破妨W(xué)性能的影響[J];塑料;2015年04期

3 桑鵬飛;劉凱;王揚(yáng)威;;熔融沉積成型中的原型翹曲變形分析[J];機(jī)械設(shè)計(jì)與研究;2015年03期

4 張龍;李旭東;郭德昌;;3D打印過程的計(jì)算機(jī)仿真[J];計(jì)算機(jī)仿真;2014年08期

5 林微;周超;蔡詩(shī)俊;張會(huì)軒;陶朝陽(yáng);;ABS樹脂拉伸性能及形變機(jī)理的研究[J];中國(guó)塑料;2013年05期

6 陳葆娟;梁延德;何福本;;熔融沉積成形試件翹曲成因的分析與優(yōu)化[J];電加工與模具;2012年04期

7 許光輝;黃泳波;鄧君;;熔融堆積成型中翹曲變形的反變形設(shè)計(jì)研究[J];東莞理工學(xué)院學(xué)報(bào);2011年03期

8 李永慶;史廷春;;FDM成型機(jī)原型精度控制[J];機(jī)床與液壓;2010年23期

9 孫春華;;FDM成形件精度預(yù)測(cè)模型的建立[J];機(jī)械科學(xué)與技術(shù);2010年03期

10 彭安華;張劍峰;;熔融堆積成型制件中層間應(yīng)力及翹曲變形研究[J];淮海工學(xué)院學(xué)報(bào)(自然科學(xué)版);2007年02期

相關(guān)博士學(xué)位論文 前2條

1 李公生;ABS樹脂高性能化制備技術(shù)及其中間體的新應(yīng)用研究[D];華東理工大學(xué);2012年

2 紀(jì)良波;熔融沉積成型有限元模擬與工藝優(yōu)化研究[D];南昌大學(xué);2011年

相關(guān)碩士學(xué)位論文 前8條

1 李驍健;基于熔融沉積成型零件的精度及溫度場(chǎng)有限元分析研究[D];蘭州理工大學(xué);2016年

2 戴岳;基于ANSYS模擬的熔融沉積快速成型精度研究[D];內(nèi)蒙古科技大學(xué);2015年

3 汪紹興;基于PLA絲材的FDM試件機(jī)械性能分析及優(yōu)化[D];大連理工大學(xué);2015年

4 高金嶺;FDM快速成型機(jī)溫度場(chǎng)及應(yīng)力場(chǎng)的數(shù)值模擬仿真[D];哈爾濱工業(yè)大學(xué);2014年

5 楊柏森;散熱條件對(duì)FDM絲材粘結(jié)質(zhì)量的影響研究[D];大連理工大學(xué);2014年

6 倪榮華;熔融沉積快速成型精度研究及其成型過程數(shù)值模擬[D];山東大學(xué);2013年

7 黃泳波;基于ANN的熔融堆積成形中翹曲變形的優(yōu)化策略研究[D];華南理工大學(xué);2010年

8 張媛;熔融沉積快速成型精度及工藝研究[D];大連理工大學(xué);2009年

，

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