纳米陶瓷的成形

本文对纳米陶瓷成形工艺的研究进展进行了综述,概括介绍了干法成形中的干压成形、等静压成形、超高压成形、原位成形和湿法成形中的挤压成形、注浆成形、离心注浆成形、渗透固化成形、凝胶浇注成形、流延成形等成形方法在纳米陶瓷成形方面的应用情况。     

陶瓷基复合材料胶态成形工艺研究进展

重点介绍了几种主要陶瓷基复合材料胶态成形工艺，包括注浆成形、注射成形、凝胶注模成形、直接凝固注模成形、温度诱导絮凝成形、水解辅助固化成形、电泳浇注成形和溶胶一凝胶法成形。对上述工艺的原理、工艺过程及特点进行了比较，并提出了陶瓷成形工艺的关键问题。     

氮化硅结合碳化硅喷嘴的成形工艺研究

通过对比分析普通石膏模注浆成形、微压注浆成形、振动注浆成形3种成形工艺在氮化结合碳化硅脱硫喷嘴成形过程中的优缺点,以及3种成形工艺坯体密度和试样抗弯强度变化,确定了氮化硅结合碳化硅最佳成形工艺.同时深入研究了振动时间对振动注浆成形密度的影响,确定了最佳振动时间.     

卫生陶瓷成形工艺及其影响因素

笔者详细介绍了卫生陶瓷成形工艺过程、成形注浆方式、压力成形工艺以及成形工艺技术的演变过程,提出了影响成形工艺和质量的因素,对卫生陶瓷企业生产具有一定的借鉴指导作用。     

陶瓷材料成形工艺的研究新进展

当前阻碍陶瓷材料进一步发展的一个关键就是成形工艺技术没有突破。本文介绍了胶态成形、固体无模成形工艺及气态成形工艺,对上述工艺的原理、工艺过程及特点进行了比较,提出了陶瓷成形工艺的关键问题,并重点介绍了水基非塑性浆料的注射成形新工艺。     

陶瓷零件胶态快速成形技术研究新进展

按照使用陶瓷材料形态的差别将其分为陶瓷粉末快速成形与胶态快速成形两大类,而胶态成形由于成形精度高,可机械加工能力好等特点而备受关注。综述了近年来发展迅速、实用性强的几种陶瓷胶态快速成形技术。着重介绍了各种技术的成形方法和原理、工艺过程及研究现状等,通过比较分析了各种快速成形制造技术在陶瓷零件制造中的特点及其存在的问题,给零件成形时不同技术的选择提供了一些参考,并对胶态成形的进一步发展进行了分析和展望。     

浅谈卫生陶瓷成形工艺及其注意事项

本文介绍了卫生陶瓷注浆成形工艺过程、成形注浆方式、压力成形工艺以及成形工艺技术的演变过程,提出了注浆成形工艺应注意的一些问题,对卫生瓷企业生产具有一定的借鉴指导作用。     

管件成形工艺研究

主要结合不同种类的管件,叙述了常见的几种成形工艺。分别阐述了拔制成形工艺、液压胀形工艺、热推成形工艺、冲压成形工艺、锻造成形工艺的制造原理及流程。     

有限元方法在玻璃成形工艺研究的应用

分析了玻璃在熔融状态下的力学性质、弹粘塑性和刚粘塑性本构方程以及玻璃成形的力学特性等,并结合玻璃成形的热力学公式,介绍了对玻璃成形的热力耦合分析的基本原理,还介绍了在玻璃成形过程中玻璃和模具之间的非线性接触、摩擦问题的求解,自动网格重划分技术.为了说明玻璃成形有限元分析的过程,最后介绍了利用三维大变形有限元方法来模拟电视显像管管屏的压制成形过程和饮料瓶吹制成形过程.     

安全无害粉末粘接型三维打印成形材料研究

为了研究安全无害粉末粘接三维打印成形材料,本文分析比较了目前常用的成形材料的安全性和成形效果,从常用的医用辅料和食品添加剂中选出了满足三维打印成形工艺要求的材料:聚乙烯吡咯烷酮(PVP)、羟丙基甲基纤维素(HPMC)、乙基纤维素(EC)、微粉硅胶。通过试验验证了各材料的成形性能和在成形过程中所起的作用,并打印出了较理想的三维打印制品。     

Plastic forming of preceramic polymers

The method of plastic forming for the preparation of green bodies from different polymeric precursors is discussed. Experiments on the influence of the pressure, the temperature and the grain size of the powders were carried out with different precursors of the system Si–C–N and the system Si–B–C–N. Optimised conditions led to lower porosities in the pyrolysed ceramic for the specimen prepared by plastic forming (PF) than for the specimen prepared by cold isostatic pressing (CIP) of the preceramic polymer. It was also possible to form dense green bodies from polymers which could not be shaped by CIP. Furthermore, the mechanism of the plastic forming behaviour of the preceramic polymers is shown for the first time.     

Ceramic molds suitable for rapid forming of CFRP composites via microwave irradiation

Carbon fiber reinforced plastic (CFRP) composites have been considered quite eminent structural materials. For more extensive applications, however, more rapid forming methods of the CFRP composites are required. As for CFRP composites with thermoplastic matrices, microwave heating and pressing with ceramic molds should be promising. In the present work, zirconia molds with varied thermal conductivity were employed to give a desired shape to the CFRP composites heated with microwave irradiation. Experimental results showed that use of the zirconia molds with smaller thermal conductivity results in shorter necessary time for the forming process. Mechanism of the notable change in the heating efficiency is discussed as well.     

The use of 3D in-mold decoration technology to form a film with printed circuits

In-mold decoration is an integrated process for plastic processes, such as printing, hot pressing, and injection molding. The process has simpler steps, the production time is shorter, products are more durable, and manufacturing costs are less than traditional methods. In-mold decoration is affected by shape, mold design and the parameters for forming, and cracking, wrinkling or stress concentration can occur. A large curvature can produce cracks and wrinkles. This study designs a series of experimental methods for film forming, hot press forming, and injection molding. The effects of various features on the quality of the hot press forming and injection molding processes are determined. A three-dimensional film forming process uses pressure thermoforming technology to form either without pretensioning, with pretensioning, and with local heating. The local heating method gives the best results. For injection molding processes, the mold temperature, the melt temperature, the injection speed, and the holding pressure are the parameters. The injection molding process is optimized using the Taguchi method, and the factor with the highest contribution is determined to be the holding pressure. The conductive line of the finished in-mold decoration product can be formed smoothly by hot pressing using local heating, and the measured resistors are almost the same after each process.     

Warpage control method during surface forming process of plastic film-reinforced flexible decorative veneer

The plastic film of the new plastic film reinforced pliable decorative veneer (PRPDSV) is used as a flexible reinforcement material and an adhesive material. It has good water resistance, impermeability, simple preparation and finishing processes, and no formaldehyde release. However, warpage phenomenon during hot pressing has been a bottleneck problem restricting its industrial development. In order to solve this problem solve, the study proposed a concave, and convex molds method, established an elastic–plastic FEA model of hot pressing processes of the PRPDSV using concave and convex molds with static/general static solution module in the nonlinear ABAQUS, and researched the effect on the performances of the PRPDSV from the parameters of temperature, pressure, and mold curvature radius theoretically and verified experimentally. Analysis results showed that the surface forming temperature had a great effect on warpage control for PRPDSV. The higher the temperature is, the smaller the curvature radius of the corresponding mold will be and the better the warpage will be. The curvature radius of the molds had a significant effect on the warpage control. Under the conditions with the same hot pressing parameters, the smaller the curvature radius is, and the better control on the warpage for the PRPDSV will be.     

SMC模压成型工艺参数对成型质量的影响

通过模压实验研究了不饱和聚酯树脂片状模塑料(SMC)模压成型工艺参数对制品成型质量的影响;以冲击强度为衡量制品性能的定量指标,通过正交实验得到了优化的SMC模压成型工艺参数,分析了各参数对冲击强度的影响,对实际生产具有一定的指导意义.     

PLASTIC AND DRYING PROPERTIES OF CERTAIN CLAYS AS INFLUENCED BY ELECTROLYTE CONTENT*

Electrodialyzed samples of several clays were saturated at pH 7 with various cations, and measurements were made to determine the effect of these cations on the workability and drying behavior of the clays. Excellent correlations were noted between the influence of these ions on clays in the plastic state and their behavior in causing flocculation or denocculation of dilute suspensions of clay. The results should be valuable for such industrial forming processes as throwing, jiggering, hot pressing, and extruding.     

PVC/竹片木塑复合材料制备工艺

以竹片为原料,复合聚氯乙烯(PVC)薄膜,通过热压–冷压工艺制备了新型PVC木塑复合材料。通过改变热压时间、热压温度和PVC添加量,研究了不同工艺条件下所制备的PVC木塑复合材料的力学性能和界面性质。实验结果表明,制备厚度为1 cm,面积为10 cm2的木塑复合材料的最佳加工工艺为:在180℃的热压温度下热压时间750 s,PVC添加量为0.3 g。加入硅烷偶联剂KH550可以有效提高PVC木塑复合材料的力学性能和界面相容性,在最佳加工条件下加入KH550为1%时,材料的胶合强度为1.212 MPa。     

Particle and Granule Parameters Affecting Compaction Efficiency in Dry Pressing

The slope of density versus log (pressure) represents the efficiency of compaction forming. A high maximum particle packing density of powders increased the pressing efficiency and the compact density. A high granule density favors a high compact density, whereas, a low granule density favors an increase in the pressing efficiency and the elimination of the intergranular pores; an optimum clearly existed. At a very low forming pressure, the compact density using granules containing a binder was lower; but at a higher forming pressure, the binder acted as a lubricant and assisted particle sliding and rearrangement which increased the pressing efficiency and compact density.     

木粉/ABS复合材料的热压成型工艺研究

用热压成型的方法制备了不同木粉用量的木粉／ABS复合材料，并对其热压成型工艺进行了探讨。结果表明，木粉用量高达60份时仍可热压成型，但以40份以下为优；通过采取加入添加剂、复合体粉料冷-机械共混与热-机械共混双重混料及热压最终成型等工艺，改善了木粉在ABS中分布的均匀性及与ABS界面的粘合性，获得了具有良好成型工艺性能的木粉／ABS复合材料。     

The choice of pressing speeds for refractories

Conclusions In the development of pressing cycles for poorly plastic bodies,the speeds should be selected bearing in mind the properties of the bodies for each stage of pressing separately.The effect obtained from increasing the rate of pressing in the first and second stages can be directed at increasing the productivity or at improving the quality of the finished goods by reducing the rate in the third stage of pressing.