# Design and Accuracy Analysis of a Micromachine Tool with a Co-Planar Driving Mechanism
## 1 Introduction  
The development trend of light, thin, short, and small consumer products has led to the demand for micromachining processes, which require highly accurate, versatile, and stable micromachine tools [1, 2, 3, 4]. The development of advanced micromachining technology to produce high-quality micro products with excellent dimensional tolerances is required. The innovation of micromachine tools plays an important role in micromachining applications in modern industry. Due to the miniaturized nature of micromachining systems, micromachining is different from conventional machining technology in terms of processes, tool, material, machine and equipment, which is challenging in the development of micromachining technology [5]. To provide the high feed resolution and accuracy required micromachining processes, high-end driving units and CNC controllers have typically been used for the micromachines, but this also leads to a high cost for the machine. Considering the practical needs of industry, it would be better to achieve excellent machining performance while simultaneously maintaining the low cost of the micromachine tools when designing the machine. To achieve high-precision feed movement, [PERSON] et al. [6] proposed the use of hydraulic bearings to enhance the accuracy of platform displacement. [PERSON] et al. [7] also proposed a special mechanism design, so that the ultra-precision machine tool would experience lower contact friction during movement in order to achieve the goal of sub-micron feed accuracy. [PERSON] et al. [8] used surface curvature as guidance for feedrate adjustment toimprove the machining efficiency of a diamond turning machining. However, this method generated micro-fluctuations in the machining process, deteriorating the surface quality. Currently, the hydraulic slide method, driven with linear motors, is widely used to enhance the feed resolution. The advantages include high speed, low friction, no backlash, and high resolution. However, it also possesses disadvantages, such as high manufacturing cost, the effect of thermal deformation error, and difficult assembly. At present, micro CNC machine tools still widely use the traditional serial-connected type structure and configuration, with a high-precision servo feed system consisting of linear guide ways and a high-level controller in order to obtain high feed resolution and high positioning accuracy. This usually results in the machine having a high manufacturing cost, which influences willingness to use them. [PERSON] et al. [9] proposed a high-precision and low-cost micromachine tool with a double-toggle-type structure. The machine was able to provide ultra-precision feed resolution and positioning accuracy without using very high-end (expensive) driving components or an expensive CNC controller. To provide more flexible capability for micromachining implementation, [PERSON] et al. [10] further proposed a design for a micromachine tool with a tilt-drive mechanism. The mechanism was able to provide not only ultra-fine feed resolution and excellent positioning accuracy for micromachining, but also an adjustable feed resolution and work range for different micromachining applications. Mechanism design, structure design/analysis, kinematics analysis and volumetric error model were studied, and hybrid error analysis and machinability tests were carried out in the study. [PERSON] et al. [11] analyzed the micro end milling kinematics and geometric error of a micromachine tool, and established a model for predicting the cutting force during micro milling. [PERSON] et al. [12] developed a methodology for evaluating and improving the dynamic performance of the machine tool in the design stage that made it possible to identify the weak machine components to avoid chatter in productivity. On the basis of the reasons mentioned above, the main objective of this study is to design a multi-DOF co-plane synchronous driving mechanism with the advantages of high accuracy, low movement inertia effect, and low cost for a 4-DOF micromachine tool.