Sequential Micromachining Research Articles

A review of sequential micro-machining: State of art approach

In the recent years, a sequential micromachining is attracting attention of researchers as it is most promising structured approach to combine and utilize advantages of different types of micromachining techniques which improves the productivity in manufacture of high precision micro features of most advanced components. Sequential micromachining is a most effective recent approach to fabricate micro features of sophisticated parts to minimize drawbacks of individual machining techniques if they were used individually. In general, this technique combines the individual micro machining techniques in a logical sequence stages to machine faster with rough cuts in the former and achieve final sizes and tolerances in the later stage. It is the opposite of hybrid micro machining in which two techniques are combined together. Sequential micromachining can be done on different machine tools or preferably on the same machine tool for better work settling accuracy, low production time and hence less rejection. Thus, it is leading to manufacture of multifunction machine centers to perform sequential micromachining on the same machine. Eventually its necessities this manufacture to be more flexible and dynamic to accommodate the future requirements in a better way. The main aim of this review paper is to give latest developments in the field of sequential micromachining processes, especially done with same machine tools and their usefulness in terms of advantages, productivity, and applications. It also gives emphasis on capabilities of future possible combinations of various techniques with high potential in this domain.

Effect of laser parameters on sequential laser beam micromachining and micro electro-discharge machining

Laser beam micromachining (LBMM) and micro electro-discharge machining (μEDM) based sequential micromachining technique, LBMM-μEDM, has drawn significant research attention to utilize the advantages of both methods, i.e., LBMM and μEDM. In this process, a pilot hole is machined by the LBMM, and subsequently finishing operation of the hole is carried out by the μEDM. This paper presents an experimental investigation on the stainless steel (type SS304) to observe the effects of laser input parameters (namely, laser power, scanning speed, and pulse frequency) on the performance of the finishing technique, that is, the μEDM in this case. The scope of the work is limited to 1-D machining, i.e., drilling microholes. It was found that laser input parameters mainly scanning speed and power influenced the output performance of μEDM significantly. Our study suggests that if an increased scanning speed at a lower laser power is used for the pilot hole drilling by the LBMM process, it could result in significantly slower μEDM machining time. On the contrary, if the higher laser power is used with even the highest scanning speed for the pilot hole drilling, then μEDM processing time was faster than the previous case. Similarly, μEDM time was also quicker for LBMMed pilot holes machined at low laser power and slow scanning speed. Our study confirms that LBMM-μEDM-based sequential machining technique reduces the machining time, tool wear, and instability (in terms of short circuit count) by a margin of 2.5 x, 9 x, and 40 x, respectively, in contrast to the pure μEDM process without compromising the quality of the holes.

A State of the art on Sequential Micro-Machining

The sequential micro-machining (SMM) is an emerging technique highly recommended for the manufacture of micro parts and also for generating micro features on parts. The review incorporates various traditional as well as non-traditional machining processes used in sequential manner. This paper focuses on recent trends in sequential micro machining combining diverse machining processes such as electrical discharge machining (EDM), laser beam machining (LBM), electrochemical machining (ECM), ultrasonic machining (USM), electrochemical discharge machining (ECDM), micro milling, micro grinding, electro-polishing, etc. The basic concepts, working principle, classification, mechanism of operation, the rationale behind the sequencing of individual machining processes etc. are described elaborately.

Experimental Investigation Into Sequential Micro Machining (SMM) for Micro Hole Drilling on SS–304

Sequential micro machining (SMM) is a strategy of machining applied for micro-part manufacturing. Due to the finding of new sequential machining combinations, the authors have presented a novel combination of micro-ECDM (µECDM) drilling and micro-ECM (µECM) finishing for producing micro-holes in SS-304 stainless steel. An experimental setup was developed indigenously to conduct both machining processes at one station. The sequential processes were employed with desirable machining parameters, during their individual execution. The most desirable parameter like machining voltage, for hole drilling by µECDM was decided by studying hole taper angle, radial overcut, etc. The µECDM generates a recast layer, to overcome the adverse effects of µECDM, with the µECM finishing applied subsequently. The experimental results of SMM indicate a reduction in hole taper angle, improved circularity, and better surface quality. The change of phase of material due to sequencing of µECDM and µECM processes was analyzed by an XRD analysis of SS-304.

Current trends and future of sequential micro-machining processes on a single machine tool

A sequential micro-machining process chain is described as the machining strategy whereby two or more micro-machining techniques are implemented in sequence on same or different machine tools. This is in contrast to hybrid micro-machining where two standalone machining technologies are integrated together. A recent surge of interest is geared towards building sequential micro-machining capabilities on a single machine tool to avoid realignment errors. One of the major advantages of performing sequential micro-machining on a single machine tool is that it suppresses repositioning errors so enabling much higher levels of accuracy (and thereby tighter tolerances), reduced rejection of machined components, and lower production time; all of these would be otherwise unachievable. Thus, multifunctional micro-machining centres are attracting global interest. Clearly, the necessity of developing reconfigurable, precise and flexible manufacturing is a key driver to this trend. This review aims to provide a critical insight into the recent trends and new classification of sequential micro-machining processes with a special focus on evaluation of such capabilities built on a single machine tool and further potentials. The machining capabilities, advantages and opportunities in the area of sequential micro-machining techniques are evaluated thoroughly and the directions for future work are highlighted.