Design and optimization of zirconia functional surfaces for dental implants applications

Zirconia is becoming a promising solution for biomedical applications, namely for dental implants, due to its biocompatibility, and mechanical and aesthetical properties. Despite the constant developments in the dentistry field, strategies to promote an effective vascularization at the implant's surface and consequently improved osseointegration are still not enough.In this sense, with the aim of promoting the vascularization at the implant's surface, zirconia surfaces with micro-channels were designed and evaluated regarding their hydrophilicity and capillarity. A CAD/CAM system was used to design and produce the specimens and different techniques were used to characterize the surfaces. The obtained average surface roughnesses are in accordance with the literature for similar materials. Results revealed that the produced materials present high levels of hydrophilicity, whether in contact with water or FBS - Fetal Bovine Serum. Additionally, micro-channels with 200 μm of width and 100 μm of depth were the ones that presented higher capillarity, thus being promising solutions for the promotion of implants vascularization, and consequently improved osseointegration.     

Further investigation on the modified hyperbolic function in the CAM16 color appearance model

In the International Commission on Illumination (CIE) color appearance model CIECAM02, a modified hyperbolic function is used to represent luminance adaptation. The same nonlinear function is also used in the new color appearance model CAM16 [Color Res Appl., 2017;42:703‐718]. Although the modified hyperbolic function seems reasonable based on physiological evidence, it has an infinite slope at the origin, which causes instability for both the forward and inverse modes of the CIECAM02/CAM16 models. In this article, various possible extensions to the nonlinear luminance adaptation function in CIECAM02/CAM16 are reviewed and evaluated. Based on these investigations, the Gill extension to the hyperbolic function that is used to represent luminance adaptation [Proceedings of 16th Color and Imaging Conference, pp. 327‐331, 2008], is recommended at both the lower end (q < q_L ) and the upper end (q > q_U ), where q is the appropriate R_c , G_c , B_c (or R_wc , G_wc , B_wc ) response. In addition, the new recommended function can be readily inverted for use in the appropriate inverse appearance model. From an extensive analysis using available experimental data sets, we also propose that, for the lower and upper limits of the luminance range in the extended model, the values q_L = 0.26 and q_U = 150 be used, respectively.     

玻璃钢缠绕制品CAD/CAM系统

玻璃钢(FRP)缠绕(FW)制品具有比强度高，比刚度大等良好的性能，广泛应用于石油、化工、航空、航天等行业。玻璃钢缠绕制品CAD／CAM系统是一个FRP FW制品设计与生产的集成系统，它实现了FRP FW制品从原材料选择到最终控制缠绕机生产的全过程的一体化，大大提高了FRP FW新产品的质量和开发效率。本文介绍了系统的基本功能和结构。     

高职机电类产学研项目转化为教学项目的研究与实施

高职院校教师在与企业开展紧密合作的过程中,开发了大量的新产品、新工艺和新技术,高职院校培养的人才要服务区域经济,对应的课程内容要与区域企业的实际相符合,因此,通过提炼可以把这些产学研项目带入到课堂中,转化为可以实施的教学项目,这样,可以提高学生的学习兴趣和成就感,从而提高教学效果,培养的人才更符合企业需求。本文以机电类的CAD/CAM实践课程为例,把产学研项目融进教学,详细介绍了课程的教学设计与教学效果。     

基于CAD/CAM软件的模具设计与制造

以塑料窗限位块为例,根据塑件的结构特征,利用CAD软件Pro/E进行模具型芯、型腔、标准模架及标准零部件的设计;利用CAM软件Master CAM进行模具型腔的加工。该种方法的应用可以大大提高模具设计效率,缩短模具设计、加工周期。     

复杂异形椭圆薄壁零件数控加工工艺分析

针对一种复杂异形椭圆薄壁零件难加工以及容易发生加工变形的特点,详细阐述了具体加工工艺步骤以及选用合适的数控加工刀具来保证椭圆内表面与环槽内表面和端面的表面粗糙度,关键步骤是选用多款CAD/CAM软件来实现零件的造型和编程,具有广泛的实践指导意义。     

基于CAD/CAM的偏心盘形凸轮设计与加工

对偏心盘形凸轮的设计原理进行了研究,并分别利用Pro/E软件和MasterCAM软件完成偏心盘形凸轮的设计和加工,大大提高了凸轮设计和加工的精度,缩短了设计时间,提高了生产效率。同时其设计和加工过程具有较好的通用性和适用性,值得借鉴。     

A cutting sequence optimization algorithm to reduce the workpiece deformation in thin-wall machining

A thin-wall part of lower stiffness can be subject to significant deformation during its cutting process. This study proposes a cutting process optimization algorithm to reduce the workpiece deformation. First, the volume to be removed is divided into a set of blocks. The proposed algorithm starts from the finished workpiece shape, with all the blocks removed. The objective of the proposed algorithm is to find a sequence of adding the blocks, such that the workpiece deformation is always smaller than the given threshold value when the cutting forces is imposed at each step. The workpiece deformation at each step is simulated by using the FEM (finite element method) simulation. By inverting the sequence of adding the blocks, the optimized sequence to remove the blocks can be obtained. Additionally, the block size can be modified to reduce the axial depth of cut to further reduce the workpiece deformation, or to increase the radial depth of cut to enhance the efficiency. Experiments are conducted to confirm the effectiveness of the algorithm to reduce the maximum workpiece deformation during the entire cutting process.     

CAX技术及其集成研究综述

在对现有CAX技术及其集成技术进行研究的基础上,首先介绍了各种CAX技术的概念、工作过程、应用现状和主要应用软件等,并分析了CAX集成技术的框架和工作流程,最后探讨了CAX技术及其集成的发展方向。     

Design,refinement, implementation and prototype testing of a reconfigurable lathe-mill

This article documents the design, refinement, and implementation of a reconfigurable machine tool that provides a flexible platform for turning and milling. Advances in the design and capabilities of machine tools drive modern industry. In fact, the expanding capabilities of the machines permit novel and economic changes in the manufacturing and design of products. After the flexible manufacturing (FMS) boom, a more recent, but no less significant, area of machine development involves the reconfiguration of milling machines. This reconfigurability can also be applied to lathe-mills. The present work demonstrates satisfactorily the reconfiguration characteristics of modularity, integrability, and convertibility. We prototype and test a completely functional bench top reconfigurable lathe mill machine implemented using a $10,000 USD budget and developed following a synthesized machine tool product development methodology that begins with concept design and cutting forces to end in prototyping. In addition to reasonable results in runout, positioning, and surface roughness, the machine demonstrates the capability to produce parts with a Cpk of 1.009, thereby demonstrating the ability to fabricate this type of machine in Mexico for the local jewelry industry.