Development of a Hybrid Photopolymer for Stereolithography

1 IntroductionRapid Prototyping (RP) was developed as a newmanufacture technique and considered a significant break-through in the field of manufacturing in the past 20years[1-4].The principle of RPis based on layer additivefabrication. Firstly, a three-dimensional object modelfromcomputer-aided design (CAD) is divided into manythinlayers by delaminatingsoftware .Thetwo-dimensionaldata of eachthinlayer control alaser beam,whichirradi-ates many materials like resin point-by-point ,and solid…     

面曝光快速成形技术的变形

从理论分析和软件模拟两方面分析了面曝光快速成形技术中的变形问题.建立了小挠度温度应力弯曲微分方程,推导出变形与层数、温差及位置等参数间的关系式.利用仿真软件AN-SYS,采用“生死单元”的方法模拟了桥型零件固化过程中的变形,验证了层数、温差及位置对变形的影响,并阐述了产生变形的原因.通过实验,验证了理论分析和软件模拟的...     

金刚石结构光子晶体的计算与制备

通过平面波法计算金刚石结构光子晶体的禁带特征,得出:当RA=0.16时,禁带宽度最大;当晶格常数a=8.5mm时,对应的最大禁带宽度为3.5GHz,对应的禁带范围为15.3～18.7GHz.利用CAD软件设计了在x,y,z三个方向上的周期数分别为2,4,6的金刚石结构的光子晶体模型,并采用立体印刷技术制备出了17.4mm×36.54mm× 54.32mm的三维微波金刚石光子晶体.最终通过HP网络测试仪对样品的禁带特征进行测试,结果表明;在晶体的＜100》方向上存在频率为14.7～18.5GHz的光子禁带,这与理论值相一致.当电磁波频率为17GHz时,对应的衰减率为-30dB.     

光固化成型中液位控制系统的研究

光固化快速成型是一种新型的加工方法,成型精度是零件加工的关键,成型过程中,树脂液位波动会影响成型精度及制作过程的进行.针对光固化成型(SL)系统中树脂液位波动的问题,本系统中采用了一种通过激光非接触反射测量的方式检测并控制液位的方法.实践表明:采用液位控制后,液位波动可以很好的控制,完全能够满足整机系统对液位控制0.003～0.014mm的精度要求.     

In‐line stepped ridge coaxial‐to‐rectangular waveguide transition with capacitive coupling

An original in‐line coaxial‐to‐rectangular waveguide transition including stepped ridged sections is presented. This device differs from the state of the art because of the coaxial inner conductor not being in electrical contact with the ridge, leading to considerable mechanical advantages. In addition to this, capacitive coupling can extend the bandwidth even with a few matching sections when compared with the traditional counterpart presenting DC contact with the first ridge. An ultra‐compact transition is designed, manufactured, and tested in back‐to‐back configuration. From measured data, a return loss better than 20 dB on a bandwidth of 1.27 GHz (12.2%) is observed in this configuration. An average insertion loss of 0.11 dB can be derived for the standalone transition.     

基于光固法的变矩器导轮快速铸造

传统的铸造因铸型制备过程复杂、生产周期长、成本高,不适合单件、小批量生产和新产品试制,研究利用光固法与熔模铸造相结合的工艺制造变矩器导轮功能样件,用于变矩器性能试验.首先利用快速成型设备制作导轮的SLA原型,随后对原型进行沾浆、淋砂、焙烧制成型壳,再经熔炼浇注后得到导轮功能样件.利用此方法,可以实现导轮的快速铸造,从而节约模具费用,缩短新产品开发周期.     

光固化中的纤维--树脂复合材料机械性能研究

对于快速成型中的光固化制作工艺,在光敏树脂中加入短纤维面制得的零件的机械性能可得到改善．制备了纤维——树脂悬浮液,探讨了纤维的添加对悬浮液粘度的影响,研究了纤维的分布方位及长度对复合材料固化物的弹性模量的影响．依据复合材料相关理论预测了固化层片及固化零件的机械性能．如弹性模量、强度．实验发现复合材料制作的样件的弹性模量和拉伸强度明显高于纯树脂固化样件,且其在后固化过程中的收缩量也比后者小．实验结果为光固化系统的制造提供最优的操作参数．     

Development and analysis of a high refractive index liquid phase Si3N4 slurry for mask stereolithography

Ceramic mask stereolithography additive manufacturing technology has the abilities of fast and accurate printing complex and personalized ceramic parts. However, since the ultraviolet light is strongly blocked by the ceramic particles in the slurry during exposure, the slurry with high refractive index ceramic particles has low cure depth, and serious light scattering. This investigation developed a curable silicon nitride slurry with a high refractive index liquid phase, which significantly reduced the refractive index difference between the liquid phase and the silicon nitride ceramic particles. The high refractive index acrylate monomer and solvent were chosen to increase the cure depth while ensuring the curing accuracy. Compared with the slurry whose liquid phase was pure HDDA, the addition of OPPEA and ACMO in the liquid phase showed a better refractive index increasing effect and the strongest cure depth and dimensional accuracy improvement. POE was verified as a suitable non-reactive high refractive solvent. The composition of 20 wt% OPPEA, 10 wt% ACMO, 40 wt% HDDA, and 30 wt% POE were optimized as the high refractive index liquid phase for 40 vol% solid phase silicon nitride slurry. A finite element analysis model of silicon nitride slurry was established, and the distribution of ultraviolet light intensity in silicon nitride slurry with high refractive index liquid phase was numerically simulated.     

基于SL原型的电弧喷涂快速模具工艺研究

介绍了使用光固化成型件作为母模进行电弧喷涂快速制模的关键工艺,包括光固化成型件制作、母模制备、金属型壳制备、背衬制作、脱模以及后处理等。工艺具有母模制备灵活、制模工艺路线短、易脱模和金属型壳表面质量高等优点。根据工艺路线,制备了1副用于注射成型的Zn-Al合金快速模具,验证了该工艺在实际工程中的应用。     

SL法用光固化树脂中聚合物填充剂对收缩性影响研究

本文用聚合物填料对SL用光敏树脂进行改性处理 ,研究了填料量对树脂粘度、密度、固化速度 ,以及对固态聚合物密度、线收缩、和体收缩的影响 ,并经激光快速成型机验证 ,获得了一种用于激光快速成型的实际可行低收缩性光敏树脂