Chiara Ravasio

Micro-electro discharge machining drilling of stainless steel with copper electrode: the influence of process parameters and electrode size

This article is about the implementation of an acquisition system for the measurement of micro-electro discharge machining process parameters and the statistical analysis of their influence on the process performance. The micro-electro discharge machining drilling of 316L stainless steel with copper tubular electrodes was studied and the exchanged power was taken into account as a comprehensive variable able to represent the effect of the peak current and voltage on the final result. The direct proportionality between the exchanged power and the nominal process parameters was verified. A linear and non-linear regression approach was used in order to obtain predictive equations for the most important aspects of micro-electro discharge machining process, such as the machining time and the electrode wear.

Electrical Discharge Machining of Micro Holes on Titanium Sheets

Micro-Electrical Discharge Machining (μEDM) has become a widely accepted non-traditional material removal process for micro-manufacture of conductive materials considered difficult to be cut using traditional machining technologies. Moreover, EDM is an ideal process for obtaining burr-free micron-size apertures with high aspect ratios. Aim of this work was to investigate the feasibility of drilling micro holes on titanium using μ-EDM technology. Titanium plates having a thickness equal to 0.5 mm were taken into account and the holes were performed using a carbide electrode having a diameter equal to 0.3 mm. The Design Of Experiment (DOE) method was used for planning the experimental campaign and ANOVA techniques were applied to study the relationship between process parameters and final output. In particular, the most important process parameters such as peak current, pulse duration, frequency and electrode rotation speed were investigated as a function of material removal rate, wear rate and machining accuracy. Geometrical and dimensional analyses were carried out on micro-holes using both optical and scanning electron microscopes to evaluate both the over cut and the rate of taper.Copyright

The effects of electrode size and discharged power on micro-electro- discharge machining drilling of stainless steel

This article is about the measurement of actual micro-electro-discharge machining parameters and the statistical analysis of their influence on the process performances. In particular, the discharged power was taken into account as a comprehensive variable able to represent the effect of peak current and voltage on the final result. Thanks to the dedicated signal acquisition system, a correlation among the discharged power and the indexes representing the process parameters was shown. Finally, linear and non-linear regression approaches were implemented in order to obtain predictive equations for the most important aspects of micro-electro-discharge machining, such as the machining time and the electrode wear.

Product Cost Modelling for Micro-EDM Drilling

The recent miniaturization of components in manufacturing has increased the production of lightweight and sophisticated systems in many different industrial fields. Micro Electro Discharge Machining (micro-EDM) is one of the most extensively used contactless and chipless machining processes. Although it is one of the most used technology, there are a few research works which investigate the economic implications of this machining. This paper reports a model cost to estimate μEDM-machining costs, including fixed and variable costs. A case study was presented taking into account micro holes on stainless steel obtained using different electrode materials. The capability of the model was demonstrated.

Influence of micro injection moulding process parameters on mechanical characteristics of POM and POM/CNT composites

Micro injection moulding is one of the most used thermoplastic technology for the manufacturing of miniaturized products, due to the high productivity of the process. Thermoplastic micro manufacturing has reached nowadays an incredible spread: polymeric components are used in several fields, such as biomedical, IT, telecommunication, automotive and aerospace. In recent years, an innovation in polymer area was the addition of fillers on the pure polymer, in order to improve the physical properties and/or to reduce the cost of the composite. The aim of the present work is to carry out a comparison between the mechanical properties of POM base material and POM filled with carbon nanotubes micro injected using different process parameters - melting temperature, injection speed and holding pressure. Uniaxial mechanical tests were performed to obtain the main mechanical properties: yield stress, deformation at break and stress at break. The results, analyzed with Analysis of Variance statistical approach show that the mechanical response of the micro¬ specimens is mainly affected by the CNT presence, whereas the other factors seems to play only a secondary role. The presence of CNT induces a remarkable increase in the mechanical resistance, but drastically reduces the material ductility.

Electrical discharge machining of micro holes on titanium sheets

Micro-Electrical Discharge Machining (μEDM) has become a widely accepted non-traditional material removal process for micro-manufacture of conductive materials considered difficult to be cut using traditional machining technologies. Moreover, EDM is an ideal process for obtaining burr-free micron-size apertures with high aspect ratios. Aim of this work was to investigate the feasibility of drilling micro holes on titanium using μ-EDM technology. Titanium plates having a thickness equal to 0.5 mm were taken into account and the holes were performed using a carbide electrode having a diameter equal to 0.3 mm. The Design Of Experiment (DOE) method was used for planning the experimental campaign and ANOVA techniques were applied to study the relationship between process parameters and final output. In particular, the most important process parameters such as peak current, pulse duration, frequency and electrode rotation speed were investigated as a function of material removal rate, wear rate and machining accuracy. Geometrical and dimensional analyses were carried out on micro-holes using both optical and scanning electron microscopes to evaluate both the over cut and the rate of taper.Copyright

Characterization Of An EBL System: The Influence Of Process Parameters On Thickness Resist And Engraving Shapes

In LIGA process, the low flexibility due to the use of masks might be overcome using the electron beam of a scansion electron microscope (SEM) instead of the synchrotron radiation. In this way, through the vector control of the beam, it is possible to irradiate a specific path on the resist without using any mask. Anyway, it is important to remark that the Electron Beam Lithography (EBL) can not include all the applications of the X‐ray LIGA technique but it could be a valid alternative only for some specific uses. In particular, some limits concerning the impression of high thickness resists are expected. An EBL system based on a SEM was recently implemented by the authors and some tests were carried out to characterize the device performances. Aim of this work is to asses the system performances in terms of maximum impressible thickness resist and shape of the engraved entities. Several tests were carried out by varying the resist thickness and the process parameters.

Electrical discharge machining of micro holes on titanium sheets: effect of process parameters and electrode shape

Micro-Electrical Discharge Machining (μEDM) has become a widely accepted non-traditional material removal process for micro-manufacture of conductive materials considered difficult to be cut using traditional machining technologies. Moreover, EDM is an ideal process for obtaining burr-free micron-size apertures with high aspect ratios. Aim of this work was to investigate the feasibility of drilling micro holes on titanium using μ-EDM technology. Titanium plates having a thickness equal to 0.5 mm were taken into account and the holes were performed using a carbide electrode having a diameter equal to 0.3 mm. The Design Of Experiment (DOE) method was used for planning the experimental campaign and ANOVA techniques were applied to study the relationship between process parameters and final output. In particular, the most important process parameters such as peak current, pulse duration, frequency and electrode rotation speed were investigated as a function of material removal rate, wear rate and machining accuracy. Geometrical and dimensional analyses were carried out on micro-holes using both optical and scanning electron microscopes to evaluate both the over cut and the rate of taper.Copyright