微小齿轮金属注射成形收缩机理与模具预控设计方法研究

The rapid growth of the market for microelectromechanical product causes a increasing demand for high precision micro gears. Metal injection molding (MIM) has many advantages for the mass production of such gears, but the problems of controlling the forming accuracy are not solved satisfactory. High and anisotropic shrinkage rates during the MIM process are serious obstacle to precision micro gears production. In order to improve the profile accuracy, the proposed project focuses on the process of mixing, injecting, debinding and sintering. Considering the influence of process parameters and injection mold control design on profile accuracy, adopting the simulation, experiment and data mining. To the analysis of the phenomenon of profile shrinkage, we derive the key elements of this effect, establish a mathematical model of the shrinkage of gears with modules between 0.1mm and 1.0mm. Based on shrinkage rate model, one can realize the active design of the necessary mold. This technology will solve the problem of anisotropic shrinkage process of micro gear MIM, so micro gears developing to high-volume, low cost and high precision manufacturing. This provide a needed theoretical support for the industrialization of metal injection molding gear.

微小齿轮的大批量、低成本制造是目前微型机电系统领域急需解决的难题，金属注射成形工艺的出现为其提供了途径，但目前存在的问题是齿形精度难于控制，成为制约微小齿轮大批量生产的瓶颈。为此，本项目以确保齿形精度为核心，以模数为0.1mm-1mm之间的铁镍合金材料为主的微小齿轮为研究对象，围绕金属注射成形的关键工序－混炼、注射、脱脂与烧结，采用模拟仿真、多因素正交实验等方法，从成形工艺参数和注射模具设计两方面，探明影响齿形各向异性收缩特性的关键要素，掌握收缩机理，建立收缩率全方位数学模型，实现对注射模具收缩率的预控设计，从而解决微小齿轮金属注射成形齿形不易控制的难题。本项目的研究成果不仅有利于揭示微小齿轮金属注射成形异向收缩机理，还将为微小齿轮金属注射成形大批量、高精度制造奠定理论基础，具有重要的理论意义和工程应用前景。

本项目针对微小齿轮在金属注射成形过程中的各向异性收缩特性，以提升齿轮成形精度为核心，围绕金属注射成形的关键工序－混炼、注射、脱脂与烧结等展开研究。提出了基于光学三维全齿扫描的测量方法，探明了齿轮在各个方向上的收缩规律，并发现了金属注射成形微小齿轮的缩腰现象；提出了基于模拟仿真、多因素正交实验、神经网络与实际试验相结的方法，探明并厘清影响齿形各向异性收缩特性的关键要素；掌握了收缩机理，建立了基于神经网络算法对微小齿轮收缩率预控的数学模型和软件系统；提出了基于深度学习模具三维点云误差补偿的主动设计方法，为金属注射成形高精度模具设计提供了理论指导。本项目的研究成果为微小齿轮金属注射成形大批量、高精度制造奠定理论基础，具有重要的理论意义和工程应用前景。