基于FDM的低熔点金属牙模制备方法研究

发布时间：2018-06-08 08:04

本文选题：3D打印技术 + FDM成型技术　；参考：《兰州理工大学》2017年硕士论文

【摘要】：3D打印技术经过近几年的发展已经越来越多的被应用到生产制造领域,3D打印技术以“增材制造”技术为原理,突破了传统制造技术的许多限制,在复杂零件、快速模具制作、创新设计等方面有着传统制造技术方法无法比拟的优势,尤其在模具开发与快速模具制作方面得到了广泛应用。熔融沉积快速成型技术(FDM)作为最基础的3D打印技术,目前已得到广泛应用,FDM成型技术可以将三维几何模型快速、准确的转化为具有一定功能的原型件。本课题以FDM成型技术为基础,并以低熔点金属材料为打印材料,制作具有一定精度且可用于熔模铸造的低熔点金属牙齿模型。重点对低熔点金属材料打印方法、成型过程中丝材的受力分析、喷头温度场分布情况、喷头出口压强分布情况、低熔点金属牙模制备方案和牙模成型质量进行了相关分析与研究。本文首先从理论上分析了FDM成型技术的供丝与出丝过程,在此基础上对打印过程中丝材的受力情况进行了理论分析,得出进给力与挤出阻力的数学模型;同时分析了温度对丝材受力情况的影响机理,得出有温度场影响时进给力与挤出阻力的数学模型。并通过ANSYS Workbench有限元分析软件对打印过程中喷头温度场分布情况、喷头出口处压强分布情况做了仿真研究,计算得到具体的进给力与挤出阻力。通过相关分析与计算,得出低熔点金属材料打印温度的确立方法。其次,对几何模型格式转换误差、分层误差、成型系统误差、材料收缩率导致的误差、喷头部分导致的误差以及后处理误差等因素的形成机制与相关计算方法进行了分析,并提出通过减小STL弦高及分层厚度、选用低收缩率丝材、合理选择喷头温度以及合理匹配出丝速度与填充速度等来提高牙模成型质量。最后,对打印过程中的重点参数设置方案进行了相关分析,主要包括分层厚度的设置、打印温度的设置、挤出速度与填充速度的设置以及轮廓补偿设置等。通过三维设计软件建立牙齿模型并进行分层处理,最终以低熔点金属丝材为打印材料,通过FDM成型技术制得低熔点金属牙齿模型,并对不同打印温度与分层厚度下的成型质量进行了对比分析和评价。
[Abstract]:Through the development of 3D printing technology in recent years, 3D printing technology has been applied more and more in the field of production and manufacturing. The principle of 3D printing technology is "material increasing manufacture" technology, which breaks through many limitations of traditional manufacturing technology and makes complex parts and rapid die making. Innovative design has unparalleled advantages in traditional manufacturing technology, especially in mould development and rapid mold making. As the most basic 3D printing technology, the fused deposition Rapid Prototyping (FDM) technology has been widely used to transform 3D geometric models into prototypes with certain functions. Based on FDM technology and low melting point metal material, a low melting point metal tooth model with certain precision and can be used in investment casting is made. Focusing on the printing method of low melting point metal material, the stress analysis of wire during forming, the distribution of spray head temperature field, the distribution of nozzle outlet pressure, The preparation of low melting metal molds and the quality of molds were analyzed and studied. In this paper, firstly, the feeding and drawing process of FDM forming technology is analyzed theoretically. Based on this, the force of wire in printing process is analyzed theoretically, and the mathematical model of feed force and extrusion resistance is obtained. At the same time, the influence mechanism of temperature on the stress of wire is analyzed, and the mathematical model of feed force and extrusion resistance under the influence of temperature field is obtained. Through ANSYS Workbench finite element analysis software, the distribution of nozzle temperature field and the pressure distribution at nozzle outlet are simulated, and the specific feed force and extrusion resistance are calculated. Through correlation analysis and calculation, the method of determining the printing temperature of low melting point metal material is obtained. Secondly, the formation mechanism and calculation methods of geometric model format conversion error, layering error, molding system error, material shrinkage error, nozzle part error and post-processing error are analyzed. It is proposed to improve the quality of tooth die by reducing STL chord height and delamination thickness, selecting low shrinkage silk material, reasonably selecting nozzle temperature and matching wire speed and filling speed. Finally, the key parameter setting scheme in the process of printing is analyzed, including the setting of layer thickness, the setting of printing temperature, the setting of extrusion speed and filling speed, and the setting of contour compensation. The tooth model was built by 3D design software, and the low melting point metal wire was used as printing material, and the low melting point metal tooth model was made by FDM technology. The molding quality under different printing temperature and delamination thickness is analyzed and evaluated.
【学位授予单位】：兰州理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG241

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