Injection Molding of Signal Generators for Hallsensor-Arrays

本计画将探讨射出成型法生产多极磁铁时，各种制程参数对磁极间距精度的影响。极距精度对于使用所谓的“霍尔效应传感器阵列”精确检测角度非常重要，霍尔效应传感器阵列可用于旋转编码器以确定旋转角度。霍尔效应传感器阵列达到了以前为光学编码器保留的位置分辨率。然而，先决条件是极宽度的高精度，因为使用“霍尔效应传感器阵列”的角度确定的精度强烈地取决于每个极的宽度的精度。例如，霍尔阵列AS 5304中0.1 mm的极宽偏差会导致大约0.025 mm的测量误差。对于所谓的“霍尔效应传感器阵列”，主要使用磁各向同性的弹性磁带，在附加的制造步骤中，通过特殊的多极磁化装置在复杂的过程中磁化。但是也可以使用各向异性磁极取向的磁环，其可以在注射成型中直接多极对准。这将允许用于精确角度传感器的信号发生器的非常经济的“非工具”制造。注塑成型工艺还提供了将这些磁环与其他功能元件（如衬套、轴、齿轮或磁性传感器）组合的机会，这些功能元件可以直接在两次注塑成型或嵌件成型工艺中制造。通过注塑成型的磁性填料在注射和保压过程中进行定向。在这些阶段中，填料颗粒处于运动中，并且聚合物基质的粘度非常动态地变化。这可能导致磁体内部多极结构的形成不准确。对使用注射成型磁化磁铁的一个技术要求，就是对影响磁极宽度精度的因素进行阐述，以达到最精确的磁极为目标。由于峰值通量密度的高度与角度确定的准确性无关，因此本项目将不研究决定峰值通量密度的变量。本研究项目的目的是系统地研究材料、工艺（选通，工艺参数）以及工艺行为的建模和仿真以及用于制造精确的信号发生器

In this project, the effects of various process parameters on the pole pitch accuracy in the production of multipolar magnets by injection molding will be investigated. The pole pitch accuracy is very important for the accurate detection of the angle with so-called "Hall-effect sensor arrays" that can be used in rotary encoders for determining the rotation angle. The Hall-effect sensor arrays reach the position resolutions that previously were reserved for optical encoders. The prerequisite, how-ever, is a high accuracy of the pole width, since the accuracy of the angular determination with the "Hall-effect sensor arrays" strongly depends on the precision of the width of each pole. For example a pole width deviation of 0.1 mm in the hall array AS 5304 causes a measurement error of approximately 0.025 mm. For the so-called "Hall-effect sensor arrays" mainly magnetically isotropic, elastic magnetic tapes are used, which are magnetized in a complex process by means of special multipolar magnetization devices within an additional manufacturing step. But it would be also possible to use an ansisotropic pole-oriented magnetic rings which can be aligned multipolar directly in injection molding. This would allow very economical "off-tool" manufacturing of signal generator for the precise angle sensors. The injection molding process also provides the opportunity to combine these magnetic rings with other functional elements, such as bushings, shafts, gears, or magnetic sensors, that can be manufactured directly in the two shot injection molding or insert molding process.The magnetic filler orientation by injection molding takes place during the injection and holding pressure. In these phases, the filler particles are in motion, and the viscosity of the polymer matrix changes very dynamically. This can lead to inaccuracies in the formation of the multi-polar structure inside the magnet. A technical requirement for the use of the injection molding magnetized magnets, is the elaboration of the factors influencing the accuracy of the pole width to achieve the the most accurate pole as a target. Since the height of the peak flux density is not relevant for the accuracy of the angle determination, the variables that determine the flux densities at peak will be not investigated under this project.The aim of this research project is the systematic investigation of the influences of material, process (gating, process parameters) and geometry on the pole pitch as well as the modeling and simulation of the process behavior and derivation of design rules for the manufacturing of precise signal generators.