Papers by Keyword: Micro Machining

Abstract: Fine micro grooves of various depths and pitches were fabricated on brass surface by ultraprecision micro cutting, and the effects of groove geometry and orientation on surface wettability were investigated. Results showed that the contact angle of a liquid drop changes significantly with the depth and orientation of the grooves. By optimizing the grooving conditions, the contact angle was increased to about twice that of a flat surface. Effects of crystal grain boundaries in the workpiece material and effects of cutting conditions on burr formation during micro grooving were studied by both experiments and finite element simulation.

Abstract: Machine tools for micro machining are so far not adapted to work piece sizes and process forces. They feature hardly any modularity and do not allow reconfiguration in a significant process change. One possibility to adapt the machines is to produce them from plastic or composite materials through generative methods. This “printed” machine is a reconfigurable, monolithic module, in which drives are integrated. By a cooperative motion generation, larger workspaces can be realized while the installation spaces decreases. This gives the possibility to use alternative drive technologies for example piezo-drives. Based on these methods, two small generatively produced machine tools are designed. These machine tools use two different drive principles. The first machine tool is equipped with ball screw drives which are cost efficient and space saving. The second machine tool uses piezo-actuators, which are very dynamic in motion generation. Further has to be examined, which tolerances and rigidities are needed at critical points and which parts can be produced generatively and which in a conventional way.

Abstract: This scientific contribution presents a novel concept and design of a hydraulic inchworm feed drive based on an electrorheological suspension. This feed drive is ought to power Micro Machining Units (MMU) of Square Foot Manufacturing (SFM) modules. The transfer of energy is conducted by an electrorheological suspension, a field-responsive fluid that allows the use of small, rugged and simple micro valves. Both of the presented feed drive’s prototypes comprise electrorheological micro valves as primary actuators and flexible metal bellows as secondary actuators in two configurations. The combination of electrorheological micro valves with flexible metal bellows allows a very compact and sealed design that avoids dynamic seals and therefore leakages making the electrorheological inchworm feed drive suitable for a wide spectrum of motion solution including clean room applications.

Abstract: The growing demand for micro products of hard and brittle materials requires suitable manufacturing processes, which serve high structure quality and accuracy. Therefore, micro pencil grinding tools are used. While grinding hard and brittle materials the structure quality and accuracy depends on the material removal mechanism. This mechanism is a complex interaction between the process parameters, the material response and the tool geometry. In this paper the influence of the process parameters, particularly the cutting speed and the feed rate, on the material removal mechanism are discussed. Furthermore, a method for the analysis of the structure quality and accuracy and within the material removal mechanism is shown.

Abstract: This paper introduced about the in-process vibration testing method for small diameter endmill. By this method, the natural frequency and modal parameters such as mass, damping, and stiffness of the milling tool can be determined in the milling process. An oscillation of the vibrator is controlled by the function generator to apply the impact force at the appropriate cutting period. The measurement setup can determine the compliance curve by the measurement signals of the exiting force and tool deformation. To evaluate the feasibility of the new method, vibration tests were performed on a square endmill which has the diameter of 4 mm in the milling on brass material. Results of vibration tests show that modal parameters of the specific vibration mode can be determined by the new developed method.

Abstract: In this paper, feasibility of laser percussion drilling on highly reflective materials i.e., Al5052 using an assisting magnetic field was explored. During the laser percussion drilling, the Lorentz force generated by the assisting magnetic field affects the laser-induced plasma and results in significant influence of the laser percussion drilling. The magnetic field simulation was performed to investigate the field strength of the circular hollow permanent magnet. The influences of magnetic field and the laser radiation energy on the penetration depth and inlet diameter were examined.

Abstract: Micro milling process is more favorite than other processes for its unique advantages in ultra-precision machining of miniature components with intricate three-dimensional geometrical feature made of various materials. Aiming at micro milling applications, a three-axis desktop milling machine tool with linear motors and nano-meter linear scales has been introduced. Natural granite is used as the frame material and air-bearing cylinders are used for z-axis gravity balancing. Finite element method is applied to the design and optimization of the machine structures. The designed machine adopts linear motors and 5nm resolution linear scale using an open control architecture. The workspace is 100mm×100mm×100mm and the overall size is 610mm×650mm×630mm. Experimental evaluations show the sub-micron machining feasibility of the introduced machine.

Abstract: The parametric thermal field analyses were realized by the finite element method. The analysis was run in the software solver COSMOS/DesignSTAR thermal. The thermal module makes possible to realize cases of the thermal dependences on the material properties. Material data can be entered as a function of the temperature. The thermal and physical characteristic of the polymeric materials are changed very expressively. The output of the analysis was temperature distribution described by various colors and assigned values in the spectrogram.

Abstract: This article presents some possibilities of laser micro-machining. Results of the laser micro-machining surface quality of product and his utility in specific application depend on the laser parameters and the polymer material type. From the obtained scientific knowledge it follows, that the character of surface machined by laser depends on thermal conductivity of polymer. The action of laser beam is best shown on specimens from PMMA, therefore tests were carried out with this material. Optimal parameters of CO2 laser for used material are presented in given study. Visual evaluation of action laser ray on surface of PMMA was made also.

Abstract: Abrasive jet micromachining (AJM) is a promising technology for processing brittle materials. Based on an experimental study of hole and groove machining on an amorphous glass by abrasive air jet, the effects of processing parameters on the produced structure profile such as groove width or hole diameter, depth of cut and kerf taper angle are analyzed. It shows that the stand-off distance has a significant effect on the kerf width. Both the hole diameter and kerf width increase notably with an increase in stand-off distance. Positive correlation has been found between the depth of cut and air pressure. Under the same cutting conditions, low taper angle can be achieved when using small nozzles.