60型熔融沉積FDM3D打印機設計（含CAD圖紙）,60,熔融,沉積,FDM3D,打印機,設計,CAD,圖紙 畢業(yè)設計題目： 60 型熔融沉積 FDM3D 打印機設計畢業(yè)設計要求及原始數(shù)據： 1、原始數(shù)據 快速成型是 20 世紀 80 年代發(fā)展起來的一種新技術，是制造領域的一次重大突破，快速成型技術是由 CAD 模型直接驅動，快速制造出任意復雜形狀的三維實體技術。在眾多的快速成型工藝中，熔融沉積是代表性的工藝之一，本設計就是針對這種工藝進行設計的一種快速成型的設備。 要求：成型體積：600*600*400；噴頭定位精度：0.01mm；Z 向定位精度：0.01mm 加熱板、絲桿及直線導軌軸等的總重量約 15kg；最大成型體積重量：約為 14KG； 噴頭最大運行速度：60mm/s； 2、畢業(yè)設計（論文）要求 （1）任務要求 全面了解設計任務書，掌握設計意圖，明確設計任務，根據原始數(shù)據，分析打印機裝置的組成結構。擬定打印機裝置的傳動系統(tǒng)設計方案，通過比較分析， 確定經濟合理的傳動系統(tǒng)并且進行設計與計算、對關鍵部件進行強度與剛度校核繪制裝配圖、部件圖和部分零件圖。同時完成相應的計算說明過程。主要任務如下： ①畢業(yè)設計（論文）開題報告； ②文獻綜述&外文翻譯； ③設計、計算、繪制相應設計內容的技術圖紙； ④畢業(yè)設計說明書。 （2）時間進度要求 序號 時間 周次 指導教師工作及要求 1 2021.3.22-2021.3.28 第 1 周 按任務書，查閱相關文獻、撰寫文獻綜述、翻譯外文資料 2 2021.3.29-2021.4.4 第 2 周 開題報告的撰寫 3 2021.4.5-2021.4.11 第 3 周 審核開題報告，進行開題答辯 4 2021.4.12-2021.5.9 第 4-7 周 試驗研究或設計階段，繪制相關圖紙，編寫設計說明書 ， 5 2021.5.10-2021.5.16 第 8 周 畢業(yè)設計期中檢查 6 2021.5.17-2021.5.30 第9-10 周 修改相關圖紙，完善畢業(yè)設計說明書 7 2021.5.31-2021.6.6 第 11 周 論文查重、修改論文 8 2021.6.7-2021.6.13 第 12 周 打印裝訂、指導老師與評閱老師賦分、畢業(yè)答辯 畢業(yè)設計（論文）主要內容： 1、設計圖樣要求 圖紙（裝配圖、零、部件圖）表達清晰、正確，標注、繪制采用國家最新標準； 圖紙的布置要合理。 2、畢業(yè)設計說明書 設計依據可靠，參數(shù)選用合理，結構設計強度及剛度校核、計算準確，內容完整，中英文摘要與科技論文必須做到準確無誤。對主要傳動方案進行比較和選擇、并可行性論證。對主要的零部件進行動力的計算，強度、剛度的校核。 畢業(yè)設計說明書參考文獻 20 篇以上，其中外文文獻不少于 5 篇。原則上所涉 及的參考文獻論文資料為近 5 年出版發(fā)表。學生應交出的設計文件： 設計成果要求：提交紙質資料（打印和部分手工繪制圖紙）和電子文檔資料 圖紙使用 AutoCAD 軟件繪制，文件為*.dwg 格式。設計說明書資料為*.doc 格式。 1、開題報告。 2、文獻綜述&外文翻譯：按《山西能源學院本科畢業(yè)設計（論文）撰寫規(guī)范執(zhí)行。 (1) 文獻綜述：字數(shù)不少于 3000 字； (2) 外文翻譯：外文翻譯必須與畢業(yè)設計課題相關，字符不少于 5000 字符， 并標明文章出處。 3、畢業(yè)設計說明書 1 份，字數(shù) 2-2.5 萬字。按《山西能源學院本科畢業(yè)設計 （論文）撰寫規(guī)范》執(zhí)行。 ４、圖紙： 圖紙折合量不小于 2 張 A0。包括裝配圖、關鍵部件圖、關鍵零件圖 。 》 主要參考文獻（資料）： 工具書 [1]《機械設計手冊》聯(lián)合編寫組編.機械設計手冊.中冊.[M].北京.化學工業(yè)出版 [2]《機械制造技術》機械工業(yè)出版社，主編：吉衛(wèi)喜，2001.5 [3]《機械制造裝備設計》機械工業(yè)出版社，主編：關慧貞參考資料 [1] 余冬梅,方奧,張建斌.3D 打印:技術和應用[J].金屬世界,2013(06):6-11. [2] 劉紅光,楊倩,劉桂鋒,劉瓊.國內外 3D 打印快速成型技術的專利情報分析 [J].情報雜志,2013,32(06):40-46. [3] 李小麗,馬劍雄,李萍,陳琪,周偉民.3D 打印技術及應用趨勢[J].自動化表，2014,35(01):1-5. [4] 李青,王青.3D 打印:一種新興的學習技術[J].遠程教育雜志,2013,31(04):29-35. [5] 張學軍,唐思熠,肇恒躍,郭紹慶,李能,孫兵兵,陳冰清.3D 打印技術研究現(xiàn)狀和關鍵技術[J].材料工程,2016,44(02):122-128. [6] 王雪瑩.3D 打印技術與產業(yè)的發(fā)展及前景分析[J].中國高新技術企業(yè),2012(26):3-5. [7] 郭振華,王清君,郭應煥.3D 打印技術與社會制造[J].寶雞文理學院學報 (自然科學版),2013,33(04):64-70. [8] 唐通鳴,張政,鄧佳文,錢素艷,李志揚,黃明宇.基于 FDM 的 3D 打印技術研究現(xiàn)狀與發(fā)展趨勢[J].化工新型材料,2015,43(06):228-230+234. [9] 樊金光,馬杰.S 形曲線算法在FDM3D 打印機中的應用[J].河北工業(yè)大學學報，2016,45（06）:1-8. [10] 朱金龍,趙寒濤,吳岡.大幅面工業(yè)級熔融沉積式 FDM3D 打印機[J].自動化技術與應用,2016,35(01):115-118. [11] 任南南，任小穎.3D 打印技術對個性化設計的影響[J].山西大同大學學報，2019,33（01）. [12] 趙寒濤,趙欣悅,董莘,邢娜.熔融沉積式 3D 打印機機架及絲杠滑軌系統(tǒng)設計[J].自動化技術與應用,2018,37(12):17-23. [13] 任曉東,陸永明.熔融沉積 3D 打印機所面臨的問題及解決辦法[J].機械工程師，2017（01）：103-104. [14] 黃子帆,馬躍龍,李俊美,李歐陽,劉軍.熔融沉積成型彩色 3D 打印機的研究[J].機床與液壓,2017,45(04):21-25. [15] 李瑞,王思雨,陸磊磊,勞潔華,張瑞.四軸機械臂式 3D 打印機[J].中國戰(zhàn) 略新興產業(yè),2018(44):163. [16] 李吉康.熔融沉積式 3D 打印機噴頭結構及常見問題分析[J].南方農機， 2018，} [17] 張文君,方輝,袁澤林,黃紀剛,董秀麗.型 FDM3D 打印設備的優(yōu)化設計與精度分析[J].機械,2018,45(01):5-10. [18] 陳繼民,王文椿,姜繆文,晏恒峰,李東方.柱坐標式 FDM3D 打印機的研制 [J].北京工業(yè)大學學報,2017,43(06):814-818. [19] 張寧寧,陳永增,阮育嬌,鄭鵬.熔融沉積成型 3D 打印機的基礎幾何誤差分析[J].計量與測試技術,2017,44(09):4-6+9. [20] 韓江,王益康,田曉青,江本赤,夏鏈.熔融沉積(FDM)3D 打印工藝參數(shù)優(yōu)化設計研究[J].制造技術與機床,2016(06):139-142+146. [21] Weimin Yang, Ranran Jian,Research on Intelligent Manufacturing of 3D Printing/Copying of Polymer,Advanced Industrial and Engineering Polymer Research,2019, [22] Paolo Minetola, Luca Iuliano, Giovanni Marchiandi,Benchmarking of FDM Machines through Part Quality Using IT Grades,Procedia CIRP,Volume 41,2016, [23] Gholamhossein Sodeifian,Saghar Ghaseminejad,Ali Akbar Yousefi,Preparation of polypropylene/short glass fiber composite as Fused Deposition Modeling (FDM) filament,Results in Physics,Volume 12,2019, [24] Felix Baumann, Manuel Sch?n, Julian Eichhoff, Dieter Roller,Concept Development of a Sensor Array for 3D Printer,Procedia CIRP,Volume 51,2016, [25] Razieh Hashemi Sanatgar, Christine Campagne, Vincent Nierstrasz,Investigation of the adhesion properties of direct 3D printing of polymers and nanocomposites on textiles: Effect of FDM printing process parameters,Applied Surface Science,Volume 403,2017, 指 導 教 師 簽 字 年 月 日 教研室主任審查簽字 年 月 日 系負責人批準簽字 年 月 日 International Conference on Manufacturing Engineering and Materials, ICMEM 2016, 6-10 June 2016, Novy Smokovec, Slovakia Reconstruction and development of a 3D printer using FDM technology Krisztián Kuna * a Kecskemét College – Faculty of Mechanical Engineering and Automation – Department of Vehicle Technology, 10 Izsáki st., Kecskemét 6000, Hungary Abstract This study, we detail the constructional selection of a machine, which operates with FDM technology. We outline the milestones of the reconstruction of the printer, the restoration of the technical documentations (Reverse Engineering), and then the calibrations and the measurement results. Based on what we have learned from the construction, we started to design our own FDM printer, which is a compact, user demand-driven device. ? 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the organizing committee of ICMEM 2016 Keywords: FDM; design; 3D printing; RE-RP; reconstruction; 1. Introduction of the FDM technology [1], [3], [4] 3D printing is additive, which means it creates the desired form with a built-up manner. This means, that the body is built up as a thin layer without a preform. The applied materials are usually some kind of plastics. There are several methods of the 3D printing technologies depending on the layer creation manner. The FDM (Fused Deposition Modeling) 3D printing technology (Figure. 1.) works on an "additive" principle by laying down material in layers; a plastic filament is unwound from a coil to produce a part. The technology was developed by Scott Crump in the late 1980s. The FDM technology needs software which processes an STL file (stereolithography file format). After that we have to slicing the model with another program for the build process. If required, support structures may be generated. The model is produced by extruding thermoplastic material to form layers as the material hardens after extrusion from the nozzle. A plastic filament is unwound from a coil and an extrusion nozzle turn the flow on and off. There is a worm-drive that pushes the filament into the nozzle at a controlled rate. The nozzle is heated to melt the material. It can be moved in both horizontal and vertical directions by a numerically controlled mechanism. The nozzle controlled by a computer-aided manufacturing (CAM) software package, and the part is built from the bottom up, one layer at a time. The stepper motors are employed to move the extrusion head. The mechanism uses an X-Y-Z rectilinear movement. 1.1. Advantages-Disadvantages of the technology The FDM printing technology is very flexible, and it is can handle with the small overhangs on the lower layers. The FDM generally has some restrictions and cannot produce undercuts without support material. Many materials are available, such as ABS and PLA among many others, with different trade-offs between strength and temperature properties. We picked the most advantageous technology from the 3D printing methods, while considering the printing quality and the level of difficulty of the building process. This technology is the FDM, i.e. the 3D extrusion. Thereafter, the next main concern was the structure of the 3D printer, more specifically: what structure we want to conform to. Fig.Conceptual sketch of FDM 2. Constructional selection [1] The most important premise is the mobility, in order to ensure a simple and fast usage of the 3D printer. Because of the mobility, it is essential to have a massive frame to prevent the printer for any kind of damage during the transportation. It was intented to make the printer out of simple parts to facilitate easy assembly and fast maintenance. Furthermore, it was an expection to make the printer compatible with electronic parts, such as standardized limit switches and to be able to print PLA and ABS. The selected construction from the founded printers was the FELIX 2.0. This printer satisfied our premises the most. We introduce the building of this printer in the following phase. Before we started building the printer itself, we made a sketch of which parts should be bought and which parts could be manufactured by us. Thanks to the manufacturer, building kits were available, so the project could be more cost-efficient, than we had bought the complete printer. By using the above mentioned, 3D printed parts and the own made ones, we created the FDM printer based on the construction of Felix Ltd., which is shown on Figure 2. Fig.2 The built FDM 3D printer We wanted to make the 3D printer in a virtual version. The purpose of this was to measure the parameters of the printer in a 3D model form, while simulating digital manufacturing. Since we bought the printed parts from the official dealer, their documentations were missing. If there would be accurate models of every part, those could be used for manufacturing spare parts or even a second 3D printer. In order to implement this, we had to use Reverse Engineering, which helped us to get the original documentation and dimensions. The essence of the manner is detailed in the next phase. 3. Reverse Engineering [1], [2], [5] Reverse Engineering is an engineering labour process, where we define the CAD geometry of a physically existing object with 3D digitalization. Reverse Engineering uses the end product to start off. Its purpose is reconstruction. Reverse Engineering is applied in the following cases: l If the new design is based on an existing part, l Hand-made master pattern, l ?Outdated” plans (no computer data, CAD drawing), l Part, tool reproduction, l Rapid prototype making. We could not have measure workpieces – with complicated geometries – with conventional measuring tools, since the caliper is not able to define complex geometries. In our case, the parts were only physical and the virtual documentations were missing. In order to make these parts re-manufacturable, we had to apply Reverse Engineering. Steps of Reverse Engineering: 1. Scanning, 2. Making a point cloud, 3. Coating, surface fitting, 4. Inspection, correction, 5. Manufacturing 3.1. Scanning Initially, we had to perform spatial scanning, alias 3D digitalization. The result of the scanning process was a point cloud, placed into a coordinate system. The CCD camera process was given for us, which is a non-contact technology. We did the measurement with a Steinbichler Optotechnik VarioZoom 200-400 3D scanner. With this manner, we were able to reproduce the virtual documentations of the existing parts. The technology is shown on the extrusion head holder unit (Figure 3.), but the other printed geometries are also made by the same manner. Fig.3 Extrusion head holder unit The projector of the scanning device – capable for accurate surface scanning – projects black and white, parallel light strips onto the surface of the object, which are deformed there. The scanner’s CCD camera initializes the breakage of the reflected light strips. The computer evaluation system calculates the attitude of the lined-up strips and then makes a point cloud. 3.2. Preliminary processing of the point cloud after scanning For the final version of the cloud, we needed 34 photographs (Figure 4.), which were combined together by finding their corresponding points. When the point cloud has been completed, it was necessary to remove the parts which did not connect to the object. (clamping elements, workbench, risers, etc.) Fig.4 Matching the recordings: The first recording is on the left,while on the right we can see the assembly of the 34 pictures. 3.3. Final processing of the point cloud The most commonly used manner of reproduction is the triangle – STL file format – coating, since it creates a simple and universal file format for every designing software. We approach the points of the point cloud with triangles (Figure 5.). The smaller the triangles, the more accurate the shape analysis. Fig. 5. Approximation of the points with triangles On the picture, we can see grey and blue surfaces at the same time. The grey surfaces give us an accurate picture of the surfaces of the part, while the blue ones refer to surface discontinuity. Here the scanning was unsuccessful, since the camera didn’t get a proper view into these areas. 3.4. The usage of RapidForm XOR for creating a model The previously created model is not yet useable directly on CNC machining or 3D printing, since the triangles have not fit perfectly onto the point clouds during the coating process, which caused dimensional errors. The software of the scanning device analyzed these errors during the triangle-coating process according to Figure 6. Fig.6 The amount of errors occured during the triangle coating process We imported the .STL file – generated by the software of the scanner device – to Reverse Engineering software (specialized on these purposes). The name of the software is: RapidForm XOR. We picked the base planes of the model. It is necessary to recognize during the usage of the software, that which steps did the previous designer follow to create the entire model. Thereafter, we used the Mesh Sketch command, which provided us cross-sectional sketches of the surface. We round drawed these sketches with approximate lines, then the real mesh size of the sketch has become definable after dimensioning them. We reconstructed the 3D CAD model with the help of the sketches (Figure 7.). We used the usual basic commands of a 3D modeling software, namely the Extrude and the Cut commands. By the result of these processes, we got the CAD model, which dimensions’ are changeable and measurable on every surface Fig. 7. CAD model of the extrusion head unit holder 3.5. Virtual prototype After using the manner – presented in the 3.4. subsection – we had complete 3D models of every printed part. After this, we created the virtual construction of the printer in an assembly environment (Figure 8.) by using Autodesk Inventor. In this way, we were able to measure the parameters of the printer in 3D model format as well, and we also found it capable for a digital manufacturing simulation. Fig.8 3D assembly of Felix 2.0 4. Constructional design of a parameterized workspace printing unit [1] The biggest disadvantage of the built construction emerged from the dimension of the printing area. The area of the tempered, heated workbench is not isolated from the environment, so there is no chance of increasing the dimensions of the printing area, because of the increased heat loss. Further problem was the transverse movement (Y) of the bench based on the below mentioned reasons: l A bench, bigger than a certain size, and the movement of a printed object would overwhelm the stepper motor of the shaft. l Further problem can be, that the overall dimension of a closed constructional frame would be increased in both directions by a formation like this. By keeping this perspectives in mind, we started to design an own printing unit. Our goal was to create a structure, where the extrusion head unit does the X-Y movement at the same time. The way of printing without a supporter unit also highly restricted the feasible geometries, since the undercut surfaces collapsed after the printing process. That is why we wanted to make the designed printing unit out of two extrusion head units. 4.1. Design of the extrusion head unit Important requirement is the running on linear bearings as well as the holding of the two extruders. The easy strain adjustment of the leading belt is an advantageous attribution as well as the adjustment of the grip during the retortion – done by the motor. The diameter of the string is 1,75 mm. 4.1.1. The retortion unit We started the design with the retortion unit, because it was relevant to know what is the distance between the output shafts of the two motors, when placing them next to each other. The mesh size of the retortion unit is based on this dimension, where we took into consideration the dimensions of the output PTOs (?5), the standardized bearing dimensions (?8), and also the thickness of the string (?1,75). By placing the motor housing next to each other demanded the need of guide cylinders (?20,55) on each of the shafts. The mesh size is shown on Figure 9. These dimensions also directly affected the distance between the extruders. . Fig. 9. Mesh size structure Fig.9 Mesh size structure It is also relevant to ensure an easy removal of the string at the retortion unit. We managed to solve this by clenching the string with the guide cylinder and the bearings – both can be found at the end of the motor. In this way we ensure the holding. We designed the retortion unit according to these perpectives, which model is shown on Figure 10. Fig.10 Model of the retortion unit 4.1.2. Structure of the extrusion head unit Since the distance between the extruders’ axes has been defined during the evolving of the retortion unit, we started building the holder unit by using these dimensions. Important perspectives were: l Minimalization of the dimensions, l Placement of the linear bearings, l Ensurance of the cooling for the protection of the elements connected to the heated units, l The slight adjustment of the strain on the leading belt. We kept in mind all requirements during the design of the extrusion head unit (Figure 11.). The head unit’s design ensures the accurate guidance, fast material flow as well as cooling. Fig. 11. The extrusion head unit We displaced the axes of the leading linear bearings in order to maintain an accurate guidance and the carrying capacity of the parts, so while it carries the weight of one motor, the other two prevent the transverse axial movement. We actualized the cooling in the following ways: l We used standardized fans l We separated the heated unit with porcelain sleeves l We created heatsinks on the stem of the extrusion unit l We created surfaces on the extrusion head holder unit for deflecting the air to the required place. l We designed an air control surface onto the workbench for instant cooling of the freshly printed material. Fig.12 Cooling around the heated area 4.2. Implementation of the X-Y movement with the new extrusion head unit The biggest challenge of the construction was to maintain two-axis movement of the head unit. Our goal was to create a paremetrized workspace, which replaces the movement of the bench and with a few modifications of certain values, it is possible to make an adequate printing area according to the desired demands. We achieved this by replacing the linear elements with beam (grinded) guided linear bearings on the X axis as well. We designed an assembly of the model (Figure 13.) in Inventor 2016 Pro software, where the entire construction refreshes itself when we modify a dimension on it, so everyone can adjust the coverage of the printing area on their own preferences. Fig. 13. The Assembly of the printing unit The dimension driven parametrization works both on X and Y axes by changing the dimensions of the appropriate beam. The shafts are moved by separate electric motors on both sides along the X axis. The motors are connected in series. In this way the path that can be done is controlled by only one limit switch. (Figure 14.) Fig.14 The Assembly of the printing unit 4.3. Belt tension We had to introduce the belt drive – applied to the moving unit – which ensures an accurate positioning. It is essential to keep the belt in the adequate tension in order to maintain the accurate guidance. For this, it is indispens able to strain the belt in the easiest way. The designed method oversimplifies the maintenance as well as the calibration. Figure 15. also shows the essence of the system in 3D. Fig. 15. Demonstration of the belt tensioning 5. Summary We detailed the building process and the Reverse Engineering of a machine which operates with FDM technology. After the experiences, gained on the builded printer, we started to design an experimental printer unit, which correct the earlier’s deficiencies. The designed printing unit is a compact, user-friendly jog unit and a head-holder console. Our goal was to create a structure, where the extrusion head unit does the X-Y movement at the same time, and to be able to print support material. That is why we designed the printing unit with two extrusion head. In conclusion, we have designed a unit to be a great assembly of an existing or a whole new machine. References [1.] K. Kun, I. Miskolczi. A. Fodor. 3D nyomtató építése és fejlesztése. Gradus Vol 2, No 2 2015. p. 155-159. [2.] J. Kodácsy, Zs. Pintér, P. Pokriva. Reverse Engineering módszerrel el?állított felületek min?sége. Kecskemét; 2003. p. 1-7. [3.] J.G. Kovács. Gyors prototípus eljárások II. Gyakorlati megvalósítások. 2002. p. 103-107. [4.] L. Morovic. Rapid technológie. Rapid Technologies. In Automation and CA Systems in Technology Planning and Manufacturings. Pozna? University of Technology, 2004, p. 177-183. ISBN 83-904877-8-0. [5.] L. Morovic. A lézeres 3D szkennelés. Fiatal m?szakiak tudományos ülésszaka. Kolozsvár; 2005. 185-188. p. ISBN 973-8231-44 國際制造工程與材料會議，ICMEM 2016， 2016年6月6日至10日，Novy斯莫科維奇，斯洛伐克 基于FDM技術的3D打印機的重建與開發(fā) Krisztian庫納 * a Kecskemét學院-機械工程和自動化學院-車輛技術系，10 Izsáki st.， Kecskemét 6000，匈牙利 摘要 在本研究中，我們詳細介紹了使用FDM技術的機器的結構選擇。我們概述了打印機重建、技術文檔恢復(逆向工程)、校準和測量結果的里程碑。根據我們從建造設計中所學到的知識，我們開始設計我們自己的FDM打印機，這是一種緊湊的，用戶需求驅動的設備。 ?2016作者。 關鍵詞:FDM;設計;3 d打印;RE-RP;重建; 1. FDM技術介紹 3D打印是累加的，這意味著它以一種疊加的方式創(chuàng)建所需的形式。這意味著，打印體是沒有預制的薄層。應用的材料通常是某種塑料。根據不同的圖層創(chuàng)建方式，3D打印技術有多種方法。 FDM(熔融沉積建模)3D打印技術(圖1)通過將材料分層放置在“添加”原理上工作;將一根塑料燈絲從線圈上松開來制造一個零件。這項技術是斯科特·克倫普(Scott Crump)在20世紀80年代末開發(fā)的。FDM技術需要處理STL文件(立體光刻文件格式)的軟件。在此之后，我們必須使用另一個程序對構建過程中的模型進行分割。如果需要，可以生成支撐結構。該模型是通過將熱塑性材料從噴嘴擠壓后硬化而形成層狀而制成的。塑料燈絲從線圈中解開，擠出噴嘴打開或關閉流量。有一個蝸桿驅動裝置以可控的速度將燈絲推入噴嘴。噴嘴被加熱以熔化材料。它可以在水平和垂直方向通過數(shù)控機構移動。噴嘴由一個計算機輔助制造(CAM)軟件包控制，零件是自下而上的，一次一層。使用步進電機來移動擠出頭。該機構采用X-Y-Z直線運動。 1.1. FDM技術的優(yōu)點與缺點 該技術的優(yōu)點-缺點FDM印刷技術非常靈活，可以處理下層的小懸垂。FDM通常有一些限制，并且不能在沒有支持材料的情況下產生底價。許多材料是可用的，如ABS和PLA等，在強度和溫度性能之間有不同的權衡。我們從3D打印方法中選擇了最具優(yōu)勢的技術，同時考慮了打印質量和建筑過程的難度。這種技術就是FDM，即3D擠壓。此后，下一個主要問題是3D打印機的結構，更具體地說:我們想遵循什么結構。 圖1 FDM概念示意圖 2. 結構選擇[1] 最重要的前提是移動性，以保證3D打印機的簡單快速使用。由于機動性，必須有一個巨大的框架，以防止打印機在運輸過程中受到任何形式的損壞。它的目的是使打印機由簡單的部件，方便組裝和快速維護。此外，這是一個期望，使打印機兼容電子部件，如標準化的限制開關，并能夠打印PLA和ABS。 從創(chuàng)建的打印機中選擇的構造是FELIX 2.0。這臺打印機最符合我們的要求。我們將在下一個階段介紹如何構建此打印機。 在我們開始制造打印機之前，我們先畫了一張草圖，說明哪些零件應該買，哪些零件可以自己制造。多虧了制造商，建造工具是可用的，所以這個項目可能比我們買完整的打印機更劃算。我們使用了上述的3D打印部件和自己制作的部件，在Felix Ltd.的基礎上創(chuàng)建了FDM打印機，如圖2所示。 圖2 FDM 3D打印機 我們想在虛擬版本中制作3D打印機。其目的是在模擬數(shù)字化制造的同時，以3D模型的形式測量打印機的參數(shù)。因為我們從官方經銷商那里買了印刷零件，他們的文件就不見了。 如果每個零件都有精確的模型，這些模型就可以用來制造零部件，甚至可以用來制造第二臺3D打印機。為了實現(xiàn)這一點，我們必須使用逆向工程，這幫助我們獲得原始文檔和尺寸。方式的本質將在下一階段詳細說明。 3. 逆向工程[1][2][5] 逆向工程是一種工程勞動過程，我們通過三維數(shù)字化來定義一個物理存在對象的CAD幾何形狀。逆向工程以最終產品為起點，其目的是重建。 逆向工程主要應用于以下幾種情況: l l如果新的設計是基于現(xiàn)有的部分， l l手工制作主圖案， l l“過時”的計劃(沒有計算機數(shù)據，CAD繪圖)， l l零件，工具復制， l l快速原型制作。 我們不能用傳統(tǒng)的測量工具測量復雜幾何形狀的工件，因為卡尺不能定義復雜的幾何形狀。在我們的例子中，這些部件只是物理的，而虛擬的文檔卻丟失了。為了使這些部件可再制造，我們必須應用逆向工程。 逆向工程步驟: 1. 掃描 2. 做點云 3. 涂料、表面擬合 4. 檢查、調整 5. 制造業(yè) 3.1掃描 首先，我們需要進行空間掃描，別名三維數(shù)字化。掃描過程的結果是一個點云，放置到一個坐標系統(tǒng)。給出了一種非接觸式CCD攝像工藝。我們使用Steinbichler Optotechnik VarioZoom 200-400 3D掃描儀進行測量。通過這種方式，我們能夠復制現(xiàn)有部分的虛擬文檔。該技術顯示在擠出頭支架單元上(圖3)，但其他打印幾何圖形也以同樣的方式制作。 圖3 擠壓頭固定裝置 掃描設備的投影儀——能夠進行精確的表面掃描——將黑白平行的光條投射到物體的表面，而物體的表面是變形的。掃描儀的CCD攝像機開始破壞反射光條。計算機評估系統(tǒng)計算出條形線的姿態(tài)，然后做出點云。 3.2掃描后點云的初步處理 對于云的最終版本，我們需要34張照片(圖4)，通過找到它們對應的點將它們組合在一起。當點云已經完成，有必要刪除那些沒有連接到對象的部分。(卡緊元件、工作臺、隔水管等) 圖4 匹配:第一張在左邊，而在右邊我們可以看到34張圖片的組合。 3.3最后處理點云 最常用的復制方式是三角- STL文件格式-涂層，因為它為每個設計軟件創(chuàng)建了一個簡單而通用的文件格式。我們使用三角形來接近點云的點(圖5)。三角形越小，形狀分析越準確。 圖5 用三角形逼近這些點 在這幅畫上，我們可以同時看到灰色和藍色的表面?；疑谋砻娼o了我們一個準確的零件表面的圖像，而藍色的表面是指表面的不連續(xù)。這里的掃描是不成功的，因為相機沒有得到一個適當?shù)囊曇斑M入這些區(qū)域 3.4使用RapidForm XOR創(chuàng)建模型 之前創(chuàng)建的模型還不能直接用于數(shù)控加工或3D打印，因為在涂層過程中，三角形并沒有完全貼合到點云上，導致了尺寸誤差。掃描裝置的軟件根據圖6分析了三角涂層過程中的這些誤差。 圖6 三角涂層過程中出現(xiàn)的誤差量 我們導入了. stl文件-由掃描設備的軟件生成-反向工程軟件(專門針對這些目的)。軟件名稱為:RapidFo